From bah13 at cornell.edu  Sun Sep  1 04:21:52 2019
From: bah13 at cornell.edu (Bernard Arthur Hutchins, Jr)
Date: Sun, 1 Sep 2019 02:21:52 +0000
Subject: [sdiy] vocoder filters
Message-ID: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>

Of courses vocoders have ?dynamic poles? (not fixed resonances) ? else what is the point?  In the original application (Voice-Coder) the idea was to exploit the redundancy in human speech (10:1 to 50:1 - - said redundancy being the repetition of many very similar ?cycles? in time that constitute a particular vowel/phoneme/syllable). Instead as few as three bandpass resonances might well represent a ?frame? of 1/5 a second.  A loss of quality of stored/transmitted speech for a vast reduction of memory required (expensive in the early days). But clearly the resonant frequencies changed with each new frame encoded.

If applied to music, probably one thinks of synthesizing singing or some DESIRABLE vocal effect.  I tried this:

http://electronotes.netfirms.com/AES4.PDF

The ?animator? worked through a series of (LFO controlled ? see Fig. 7) of POSSIBLE formant frequencies (phonemes both used and unused in a particular language).  It worked - it sounded human!  BUT basically like a human suffering from food poisoning!   Lesson learned.

-Bernie


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From colindorward at gmail.com  Sun Sep  1 07:21:29 2019
From: colindorward at gmail.com (ColinMuirDorward)
Date: Sat, 31 Aug 2019 22:21:29 -0700
Subject: [sdiy] vocoder filters
In-Reply-To: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
References: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
Message-ID: <CAGV3gy5jFOTB0En4YMyonujXNkO32J+dATw85H5fUNO_8AJy6g@mail.gmail.com>

I think maybe this has branched off from it's parent thread now, so I will
respond here. Thanks for the replies!

Take a look at speech CODECs like linear predictive coding, CELP, SPEEX,
etc. ...
A variant of this digital "vocoder" is used in the GSM baseband processing
that conveys speech over mobile phone networks with minimal bitrate

Oh I never correlated vocoding so directly with the telecom industry, but
of course it makes perfect sense that's where the tech would be developed.

Also check out Ray Wilson?s take with a very detailed writeup:
http://musicfromouterspace.com/index.php?CATPARTNO=NONE&PROJARG=VOCODER2013%2FVOCODER2013.php&MAINTAB=SYNTHDIY&SONGID=NONE&VPW=1024&VPH=500

Am I missing something? Ray Wilson's looks like fixed frequency BPFs.

If applied to music, probably one thinks of synthesizing singing or some
DESIRABLE vocal effect.  I tried this:

http://electronotes.netfirms.com/AES4.PDF


Inspiring read! I think I'll build that sawtooth phase shifter.


-Colin






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On Sat, Aug 31, 2019 at 7:25 PM Bernard Arthur Hutchins, Jr <
bah13 at cornell.edu> wrote:

> Of courses vocoders have ?dynamic poles? (not fixed resonances) ? else
> what is the point?  In the original application (Voice-Coder) the idea
> was to exploit the redundancy in human speech (10:1 to 50:1 - - said
> redundancy being the repetition of many very similar ?cycles? in time that
> constitute a particular vowel/phoneme/syllable). Instead as few as three
> bandpass resonances might well represent a ?frame? of 1/5 a second.  A
> loss of quality of stored/transmitted speech for a vast reduction of memory
> required (expensive in the early days). But clearly the resonant
> frequencies changed with each new frame encoded.
>
>
> If applied to music, probably one thinks of synthesizing singing or some
> DESIRABLE vocal effect.  I tried this:
>
>
> http://electronotes.netfirms.com/AES4.PDF
>
>
> The ?animator? worked through a series of (LFO controlled ? see Fig. 7) of
> POSSIBLE formant frequencies (phonemes both used and unused in a particular
> language).  It worked - it sounded human!  BUT basically like a human
> suffering from food poisoning!   Lesson learned.
>
>
> -Bernie
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>


-- 
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-
<https://www.instagram.com/colinmuirdorward/>
https://www.instagram.com/ssdp_synthesis/

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From sleepy_dog at gmx.de  Sun Sep  1 13:58:41 2019
From: sleepy_dog at gmx.de (sleepy_dog at gmx.de)
Date: Sun, 1 Sep 2019 13:58:41 +0200
Subject: [sdiy] vocoder filters
In-Reply-To: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
References: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
Message-ID: <b5e51728-ec7a-fe25-8b8e-e59d2dea8e1c@gmx.de>


Bernard Arthur Hutchins, Jr wrote:
> http://electronotes.netfirms.com/AES4.PDF
>
>
> The ?animator? worked through a series of (LFO controlled ? see Fig.
> 7) of POSSIBLE formant frequencies (phonemes both used and unused in a
> particular language).It worked - it sounded human!BUT basically like a
> human suffering from food poisoning!Lesson learned.
>
>
> -Bernie
>

Heh! This reminds me of my own forays into this sort of stuff a year or
so ago.

While experimenting also with analog resonator circuitry for an analog
synth chain, it dawned on me that you could synthesize speech also.
But then I heeded Gordon's advice even before he gave it (not really,
yesterday was not the first time, haha) and did that particular thing
digitally.

Starting with barely any knowledge of phonetics and stuff ... I played
with primitive ways of vocal synthesis, as it was meant to run on a
cheap MCU.

With just a bunch of digital chamberlin SVFs, and a bit of dynamic
parametrizing... (eh end noise source and crude vocal folds waveform)
Note that there wasn't even an attempt yet to morph between phonemes,
let alone halfway realistically - it's all just stupidly glued to each
other.
The fricatives are also crap, and when I started to work on that, I was
inconveniently lured out of unemployment and had no time anymore, lol!
So it sounds like some steampunk robotic plunging going on (I mean in
the 2nd example, which was, unlike the 1st, not meant to sound robotic
;)), but I swear, it's all "electric".

Excuse very much the horrid fundamental-only melody playing - hey, I
only had a bunch of resonating filters to play (poly) melodies with in
my experimental program setup, it was a quick hack, meant as a gag to
hint at what the vocals are aimed at replicating (more or less) ...
perhaps recognized by people who listened to the readio in the 1990's ;)
The bleep stuff is over at 32secs.
http://www.mediafire.com/file/hb9x78fdezxcs53/u96.ogg/file

Italians - don't complain about pronunciation ^^ (although the
intellibility isn't that high in general and I didn't have a set of
specifically italian vowels at hand, I kinda winged it)
http://www.mediafire.com/file/pxx9iez89ziyfg8/vissidarte-lessbreathy.ogg/file


- Steve

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From fluxmonk at gmail.com  Sun Sep  1 17:05:35 2019
From: fluxmonk at gmail.com (bbob)
Date: Sun, 1 Sep 2019 11:05:35 -0400
Subject: [sdiy] vocoder filters
In-Reply-To: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
References: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
Message-ID: <CABbX2d-BOoG8ZO=0UfRXpWm6EK=tPhZUEK5ZzT4dErOeFeQJqA@mail.gmail.com>

speaking of back in the day... don't forget Jim Patchell's vocal filter (
http://www.noniandjim.com/Jim/synthmodules/vocalfilter.html).  check out
the picture of the PCB - to me it is an inspiration and a thing of beauty,
but it explains why some folks might want to do it in software!  really
should build mine someday...

b

On Sat, Aug 31, 2019 at 10:25 PM Bernard Arthur Hutchins, Jr <
bah13 at cornell.edu> wrote:

> Of courses vocoders have ?dynamic poles? (not fixed resonances) ? else
> what is the point?  In the original application (Voice-Coder) the idea
> was to exploit the redundancy in human speech (10:1 to 50:1 - - said
> redundancy being the repetition of many very similar ?cycles? in time that
> constitute a particular vowel/phoneme/syllable). Instead as few as three
> bandpass resonances might well represent a ?frame? of 1/5 a second.  A
> loss of quality of stored/transmitted speech for a vast reduction of memory
> required (expensive in the early days). But clearly the resonant
> frequencies changed with each new frame encoded.
>
>
> If applied to music, probably one thinks of synthesizing singing or some
> DESIRABLE vocal effect.  I tried this:
>
>
> http://electronotes.netfirms.com/AES4.PDF
>
>
> The ?animator? worked through a series of (LFO controlled ? see Fig. 7) of
> POSSIBLE formant frequencies (phonemes both used and unused in a particular
> language).  It worked - it sounded human!  BUT basically like a human
> suffering from food poisoning!   Lesson learned.
>
>
> -Bernie
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
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From mr at analogue.org  Sun Sep  1 17:54:43 2019
From: mr at analogue.org (Mattias Rickardsson)
Date: Sun, 1 Sep 2019 17:54:43 +0200
Subject: [sdiy] vocoder filters
In-Reply-To: <62CB86078C824AC689D370C0211065B3@david78c70950b>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
Message-ID: <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>

The next level is to ponder on the unwanted higher-frequency AM effects
from controlling a vocoder band VCA with the "best" (fastest) envelope
follower, and whether a slower response could be more optimal. So much fun!
:-)

/mr


Den l?r 31 aug. 2019 23:23David G Dixon <dixon at mail.ubc.ca> skrev:

> Not really.  It?s a full-wave rectifier followed by a standard LP filter
> stage tuned to about 1/4 of the expected incoming frequency followed by a
> notch filter tuned to twice the incoming frequency.  I also use a full wave
> rectifier instead of the normal half wave rectifier, because I figure this
> gives faster integration.  This is why the ripple is at twice the incoming
> frequency, and a notch filter knocks it out nicely.  Through the judicious
> choice of gain at the LP filter, the envelope follows the waveform tops
> more or less exactly, and comes up to full strength within two periods of
> the incoming waveform, with ripple which is inconsequential.  For a 10Vpp
> waveform coming in, the envelope rides at 5V, which will turn on my favored
> linearized 2164 VCA design to unity gain.
>
>
> ------------------------------
>
> *From:* David Moylan [mailto:dave at expeditionelectronics.com]
> *Sent:* Saturday, August 31, 2019 5:26 AM
> *To:* David G Dixon
> *Cc:* synth-diy at synth-diy.org
> *Subject:* Re: [sdiy] vocoder filters
>
>
>
> Curious about this envelope follower you mention. Trade secret?
>
>
>
> On Aug 31, 2019 03:48, David G Dixon <dixon at mail.ubc.ca> wrote:
>
> Well, I know that the higher-Q filters have a longer delay, so that they
> take longer to respond to the incoming waveform.  I?m thinking that a Q of
> about 3 is probably about right, and with that, only a 4-pole filter is
> required.
>
>
>
> I?ve got a nice design for an envelope follower which responds quickly and
> has little or no ripple, so that?s not a problem.
>
>
>
> On a related note, does anyone here have problems getting the Bode plotter
> in Multisim to work consistently?  I am finding with this simulation that
> sometimes if I change the component values, the Bode plotter doesn?t work
> at all.  Also, for some simulations, changing the component values doesn?t
> change the filter response at all.  Multisim is sure glitchy.  It?s very
> frustrating.  I can sometimes fix it if I erase all of the passive
> components and load new ones with the new values, rather than just changing
> them, but that sort of thing is just complete bullshit.  Multisim is a sad
> excuse for a professional program.  There must be something better out
> there (?).
>
>
> ------------------------------
>
> *From:* Paul Perry [mailto:paulfrancisperry at gmail.com]
> *Sent:* Friday, August 30, 2019 10:22 PM
> *To:* David G Dixon
> *Subject:* Re: [sdiy] vocoder filters
>
>
>
> I don't think there is a "right" answer. To my mind, it depends on what
> one wants to do with the unit. Think about what will happen when a single
> swept tone is used to modify white noise. The low pass filter on the VCAs
> probably has a significant effect as well.
>
> paul perry Melbourne Australia
>
>
>
> On Sat, 31 Aug 2019 at 14:50, David G Dixon <dixon at mail.ubc.ca> wrote:
>
> Well, I think I might have answered my own question.  Looking again at the
> JH Living Vocoder, since Jurgen Haible?s filter responses overlap at about
> the 8dB mark, it really should not matter at all what?s going on around the
> skirt of the response, and higher-Q filters with two 2-pole stages should
> give very similar results to low-Q filters with four 4-pole stages (and be
> much much cheaper to build).
>
>
>
> I?d still appreciate if anyone has any specific insights into this
> problem.  Cheers.
>
>
> ------------------------------
>
> *From:* Synth-diy [mailto:synth-diy-bounces at synth-diy.org] *On Behalf Of *David
> G Dixon
> *Sent:* Friday, August 30, 2019 9:05 PM
> *To:* synth-diy at synth-diy.org
> *Subject:* [sdiy] vocoder filters
>
>
>
> Hey SDIY Team!
>
>
>
> I?m thinking about building a vocoder, and I have a general question about
> the bandpass filters.
>
>
>
> I?ve looked at Jurgen Haible?s Living Vocoder, and he used 8-pole filters
> with low Q.  These give a reasonably broad band with fairly steep slopes.
> He makes the filters from two pairs of LP and HP.
>
>
>
> I was thinking about using BP filter sections, but just 4-pole, and with
> higher Q (around 10).  This gives a somewhat narrower band, and the slope
> is steep near the corner, but fairly shallow around the skirt.  This idea
> uses a lot fewer components (about half as many).
>
>
>
> What I?m asking is, does anybody here have any insight into what the
> ?proper? approach to vocoder filters would be?  What is the design goal?
> Do you want significant overlap from one band to the next, or should they
> be fairly distinct?  I guess I?m just looking for some general guidelines
> and conventional wisdom.
>
>
>
> Cheers,
>
> Dave Dixon
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
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From dixon at mail.ubc.ca  Sun Sep  1 20:28:24 2019
From: dixon at mail.ubc.ca (David G Dixon)
Date: Sun, 1 Sep 2019 11:28:24 -0700
Subject: [sdiy] vocoder filters
In-Reply-To: <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
Message-ID: <C2A0703E5C5E448FA5A1224C0C4D7B04@david78c70950b>

Thing 1: I had a look at the MFOS vocoder schematic, and lo and behold, Ray
used single opamp filters!  Giving this some thought, I can design a single
opamp filter which will give more or less the same frequency response near
the corner as a double (or quadruple) opamp filter.

 

Thing 2: Looking at Jurgen Haible?s overall frequency response for all the
filters together, it looks like a series of peaks with a ?floor? at about
-3dB, and the peaks at about -1dB ? yes, that?s right, the whole action of
the filters altogether is only within about a 2-dB range of amplitude.
Hence, what is happening further down with these individual responses is of
absolutely no consequence.  I would probably opt for slightly pointier
responses near the tops to give more of a comb effect and better separation
of the channels.

 

Conclusions: I can achieve more or less exactly the same results as the JH
Living Vocoder with a quarter of the filter circuitry.  With the double
feedback filter design, one has complete control over the frequency, gain,
and bandwidth.  Hence, I would strive to position the peak at 0 dB, and to
make the slope of the response near the peak similar to the 8-pole filters
with low Q employed by JH.  With the filter design I?m using, the frequency
will be tuned by a 500-ohm trimpot ? I?m using single turn trimpots to make
tuning less suicide-inducing (I bought a bag of 100 from Electronic Goldmine
for 20 cents each).  I will simply tinker with the design until I have a
frequency response which looks very similar to JH?s filters ? it?s all on a
spreadsheet ? all I have to do is specify f_0, Q and the amplitude at f_0,
and pick a standard capacitor value, and the design is calculated
automatically.  Depending upon the Q value chosen, the filters can all take
a combination of the same two standard resistor values once the capacitor is
chosen, with the third resistor value represented by the trimpot (which is
500 ohms based on selecting a Q value of 10).

 

This is all an experiment, so I don?t expect to succeed completely on the
first attempt.  I also must confess that I haven?t really given much thought
to things such as compression, pre-amplifying the vocals, sibilance, etc,
etc, so I still have a lot of work to do.  However, I?m going to start with
the basic vocoder and expand on it as needed, rather than try to design the
whole thing from the ground up right away.  I make all my PCBs in a modular
fashion anyway, so no big deal.

 

My original idea was to make a vocoder with 88 channels ? one for each
semitone of the piano range ? with resonating filters that would ring out
with a sine wave when excited.  In this way, the device would ?sing? some
ethereal version of whatever music was fed to it, in tune.  Maybe, with
single opamp filters, this is doable.

 

 

  _____  

From: Mattias Rickardsson [mailto:mr at analogue.org] 
Sent: Sunday, September 01, 2019 8:55 AM
To: David G Dixon
Cc: David Moylan; Synth DIY
Subject: Re: [sdiy] vocoder filters

 

The next level is to ponder on the unwanted higher-frequency AM effects from
controlling a vocoder band VCA with the "best" (fastest) envelope follower,
and whether a slower response could be more optimal. So much fun! :-)

 

/mr

 

 

Den l?r 31 aug. 2019 23:23David G Dixon <dixon at mail.ubc.ca> skrev:

Not really.  It?s a full-wave rectifier followed by a standard LP filter
stage tuned to about 1/4 of the expected incoming frequency followed by a
notch filter tuned to twice the incoming frequency.  I also use a full wave
rectifier instead of the normal half wave rectifier, because I figure this
gives faster integration.  This is why the ripple is at twice the incoming
frequency, and a notch filter knocks it out nicely.  Through the judicious
choice of gain at the LP filter, the envelope follows the waveform tops more
or less exactly, and comes up to full strength within two periods of the
incoming waveform, with ripple which is inconsequential.  For a 10Vpp
waveform coming in, the envelope rides at 5V, which will turn on my favored
linearized 2164 VCA design to unity gain.

 


  _____  


From: David Moylan [mailto:dave at expeditionelectronics.com] 
Sent: Saturday, August 31, 2019 5:26 AM
To: David G Dixon
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] vocoder filters

 

Curious about this envelope follower you mention. Trade secret?

 

On Aug 31, 2019 03:48, David G Dixon <dixon at mail.ubc.ca> wrote:

Well, I know that the higher-Q filters have a longer delay, so that they
take longer to respond to the incoming waveform.  I?m thinking that a Q of
about 3 is probably about right, and with that, only a 4-pole filter is
required.

 

I?ve got a nice design for an envelope follower which responds quickly and
has little or no ripple, so that?s not a problem.

 

On a related note, does anyone here have problems getting the Bode plotter
in Multisim to work consistently?  I am finding with this simulation that
sometimes if I change the component values, the Bode plotter doesn?t work at
all.  Also, for some simulations, changing the component values doesn?t
change the filter response at all.  Multisim is sure glitchy.  It?s very
frustrating.  I can sometimes fix it if I erase all of the passive
components and load new ones with the new values, rather than just changing
them, but that sort of thing is just complete bullshit.  Multisim is a sad
excuse for a professional program.  There must be something better out there
(?).

 


  _____  


From: Paul Perry [mailto:paulfrancisperry at gmail.com] 
Sent: Friday, August 30, 2019 10:22 PM
To: David G Dixon
Subject: Re: [sdiy] vocoder filters

 

I don't think there is a "right" answer. To my mind, it depends on what one
wants to do with the unit. Think about what will happen when a single swept
tone is used to modify white noise. The low pass filter on the VCAs probably
has a significant effect as well.

paul perry Melbourne Australia

 

On Sat, 31 Aug 2019 at 14:50, David G Dixon <dixon at mail.ubc.ca> wrote:

Well, I think I might have answered my own question.  Looking again at the
JH Living Vocoder, since Jurgen Haible?s filter responses overlap at about
the 8dB mark, it really should not matter at all what?s going on around the
skirt of the response, and higher-Q filters with two 2-pole stages should
give very similar results to low-Q filters with four 4-pole stages (and be
much much cheaper to build).

 

I?d still appreciate if anyone has any specific insights into this problem.
Cheers.

 


  _____  


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of David
G Dixon
Sent: Friday, August 30, 2019 9:05 PM
To: synth-diy at synth-diy.org
Subject: [sdiy] vocoder filters

 

Hey SDIY Team!

 

I?m thinking about building a vocoder, and I have a general question about
the bandpass filters.

 

I?ve looked at Jurgen Haible?s Living Vocoder, and he used 8-pole filters
with low Q.  These give a reasonably broad band with fairly steep slopes.
He makes the filters from two pairs of LP and HP.

 

I was thinking about using BP filter sections, but just 4-pole, and with
higher Q (around 10).  This gives a somewhat narrower band, and the slope is
steep near the corner, but fairly shallow around the skirt.  This idea uses
a lot fewer components (about half as many).

 

What I?m asking is, does anybody here have any insight into what the
?proper? approach to vocoder filters would be?  What is the design goal?  Do
you want significant overlap from one band to the next, or should they be
fairly distinct?  I guess I?m just looking for some general guidelines and
conventional wisdom.

 

Cheers,

Dave Dixon

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy

 

_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy

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From rburnett at richieburnett.co.uk  Sun Sep  1 21:22:20 2019
From: rburnett at richieburnett.co.uk (Richie Burnett)
Date: Sun, 1 Sep 2019 20:22:20 +0100
Subject: [sdiy] vocoder filters
In-Reply-To: <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
Message-ID: <9915FC5ADAEC45D69273B593D3913BF8@RICHIEPC>

One way to control the spectral broadening due to the amplitude modulation 
is obviously to band-limit the VCA's control signals.  I guess most VCA CV's 
have a faster attack than release, so it's mostly limiting the attack speed 
that we're talking about here.  High order LPFs applied to the VCA CVs give 
a more favourable trade-off between settling time and residual ripple.

Another way to control the spectral broadening due to amplitude modulation 
in the VCA, and stop it bleeding into the adjacent bands, is to put the VCAs 
in-between the filter stages that make up each of the synthesis band 
filters.  This is what Roland did in their SVC-350 Vocoder.  It was probably 
done as much to filter out the PWM carrier frequency, but putting some of 
the vocoder's synthesis band filtering after the VCA helps to control 
out-of-band leakage caused by any fast VCA modulation.

On a related note, the conundrum I always face when thinking about Vocoder 
analysis and synthesis filter banks is how to deal with the bottom few 
bands...  The job of the analysis filter bank is to determine the spectral 
profile of the speech at any particular instant in time.  So ideally I want 
shed loads of closely spaced bands so that I get a fine-resolution picture 
of what the spectral profile is doing across the full speech range.  For 
instance, I might choose to use 24 bands spaced 1/4 octave exponentially to 
cover the 6 octave range from 80Hz up to 5.12 kHz.  This seems sensible as 
there probably aren't many vocal tract resonances outside this range that 
noticeably affect speech intelligibility.  However a problem arises with the 
bottom few bands.  All of the bands have the same Q and the same fractional 
bandwidth, however the actual bandwidth of the lower bands becomes only a 
handful of Hertz.  For example the bottom bands in my setup would be:

80-95Hz,
95-113Hz,
113Hz-135Hz,
135Hz-160Hz,
160-190Hz, *
190-226Hz,
226-269Hz,
269-320Hz,
320-381Hz, *
381-453Hz,
453-538Hz,
538-640Hz, *
etc...

This can lead to the frustrating situation where harmonics of the speech 
signal only fall into certain analysis bands at the low-frequency end of the 
speech range.  For example a female voice might easily have a fundamental 
frequency of 180Hz.  This would only put energy into the analysis bands 
centred around 180, 360, 540, 720 Hz, etc.  marked with the stars above, 
with nothing in the intervening bands.  This situation persists until 
eventually we get to a point where more than one harmonic of the voice 
signal starts to fit into each analysis band at some higher frequency.  Then 
the holes in the analysis spectrum disappear.

Clearly the analogue filter bank in this example is doing a poor job of 
estimating the spectral shaping of the vocal tract when the bands are made 
too narrow because they start to resolve the actual discrete spectral 
harmonics of the vocal signal.  This then leads to the situation where the 
output signal from the vocoder is very quiet unless the pitches of the voice 
and carrier inputs are related, so that harmonics of the speech and carrier 
inputs both land in the same frequency bands (>.<)  This isn't right.

The problem is that I don't know the best way around this.  I could make the 
analysis and synthesis bands wider and use less bands, but that seems a 
waste when modern DSPs have got enough grunt to run 40 bands easily.  Or I 
could make the lower frequency bands wider in an attempt to make sure that 
some harmonics of a given voice signal end up in every band at the lower end 
of the spectrum.  This is what Sennheiser seem to have done in at least one 
of their Vocoders, and it makes sense.  However, I liked the idea of having 
filter bands that are evenly spaced in octaves because I can then shift 
formants up or down easily by routing the outputs from analysis bands to 
adjacent synthesis bands across the audio range.  This isn't as simple if I 
alter the fractional bandwidths of the filters across the audio spectrum. 
The only other idea I had was to try to come up with some sort of 
interpolation algorithm to work around the "holes" in the spectral at the 
bottom end generated by the analysis filter bank which are particularly bad 
with voices that have a relatively high fundamental.

I guess ultimately I need to accept that the analogue analysis filter-bank 
paradigm is a compromise.  Ultimately the best way to estimate the vocal 
tract resonances is probably to window one complete pitch period of the 
speech signal and then FFT it to get the spectrum.  That way you get a 
continuous spectrum, instead of a line spectrum out of the analysis process.

Any thoughts and comments welcome.

-Richie,



-----Original Message----- 
From: Mattias Rickardsson
Sent: Sunday, September 01, 2019 4:54 PM
To: David G Dixon
Cc: Synth DIY
Subject: Re: [sdiy] vocoder filters


The next level is to ponder on the unwanted higher-frequency AM effects from 
controlling a vocoder band VCA with the "best" (fastest) envelope follower, 
and whether a slower response could be more optimal. So much fun! :-)

/mr



Den l?r 31 aug. 2019 23:23David G Dixon <dixon at mail.ubc.ca> skrev:


Not really.  It?s a full-wave rectifier followed by a standard LP filter 
stage tuned to about 1/4 of the expected incoming frequency followed by a 
notch filter tuned to twice the incoming frequency.  I also use a full wave 
rectifier instead of the normal half wave rectifier, because I figure this 
gives faster integration.  This is why the ripple is at twice the incoming 
frequency, and a notch filter knocks it out nicely.  Through the judicious 
choice of gain at the LP filter, the envelope follows the waveform tops more 
or less exactly, and comes up to full strength within two periods of the 
incoming waveform, with ripple which is inconsequential.  For a 10Vpp 
waveform coming in, the envelope rides at 5V, which will turn on my favored 
linearized 2164 VCA design to unity gain.





From: David Moylan [mailto:dave at expeditionelectronics.com]
Sent: Saturday, August 31, 2019 5:26 AM
To: David G Dixon
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] vocoder filters







Curious about this envelope follower you mention. Trade secret?







On Aug 31, 2019 03:48, David G Dixon <dixon at mail.ubc.ca> wrote:



Well, I know that the higher-Q filters have a longer delay, so that they 
take longer to respond to the incoming waveform.  I?m thinking that a Q of 
about 3 is probably about right, and with that, only a 4-pole filter is 
required.



I?ve got a nice design for an envelope follower which responds quickly and 
has little or no ripple, so that?s not a problem.



On a related note, does anyone here have problems getting the Bode plotter 
in Multisim to work consistently?  I am finding with this simulation that 
sometimes if I change the component values, the Bode plotter doesn?t work at 
all.  Also, for some simulations, changing the component values doesn?t 
change the filter response at all.  Multisim is sure glitchy.  It?s very 
frustrating.  I can sometimes fix it if I erase all of the passive 
components and load new ones with the new values, rather than just changing 
them, but that sort of thing is just complete bullshit.  Multisim is a sad 
excuse for a professional program.  There must be something better out there 
(?).





From: Paul Perry [mailto:paulfrancisperry at gmail.com]
Sent: Friday, August 30, 2019 10:22 PM
To: David G Dixon
Subject: Re: [sdiy] vocoder filters







I don't think there is a "right" answer. To my mind, it depends on what one 
wants to do with the unit. Think about what will happen when a single swept 
tone is used to modify white noise. The low pass filter on the VCAs probably 
has a significant effect as well.



paul perry Melbourne Australia







On Sat, 31 Aug 2019 at 14:50, David G Dixon <dixon at mail.ubc.ca> wrote:



Well, I think I might have answered my own question.  Looking again at the 
JH Living Vocoder, since Jurgen Haible?s filter responses overlap at about 
the 8dB mark, it really should not matter at all what?s going on around the 
skirt of the response, and higher-Q filters with two 2-pole stages should 
give very similar results to low-Q filters with four 4-pole stages (and be 
much much cheaper to build).



I?d still appreciate if anyone has any specific insights into this problem. 
Cheers.





From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of David 
G Dixon
Sent: Friday, August 30, 2019 9:05 PM
To: synth-diy at synth-diy.org
Subject: [sdiy] vocoder filters





Hey SDIY Team!



I?m thinking about building a vocoder, and I have a general question about 
the bandpass filters.



I?ve looked at Jurgen Haible?s Living Vocoder, and he used 8-pole filters 
with low Q.  These give a reasonably broad band with fairly steep slopes. 
He makes the filters from two pairs of LP and HP.



I was thinking about using BP filter sections, but just 4-pole, and with 
higher Q (around 10).  This gives a somewhat narrower band, and the slope is 
steep near the corner, but fairly shallow around the skirt.  This idea uses 
a lot fewer components (about half as many).



What I?m asking is, does anybody here have any insight into what the 
 ?proper? approach to vocoder filters would be?  What is the design goal? 
Do you want significant overlap from one band to the next, or should they be 
fairly distinct?  I guess I?m just looking for some general guidelines and 
conventional wisdom.



Cheers,

Dave Dixon



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Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy





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From mr at analogue.org  Sun Sep  1 22:49:53 2019
From: mr at analogue.org (Mattias Rickardsson)
Date: Sun, 1 Sep 2019 22:49:53 +0200
Subject: [sdiy] vocoder filters
In-Reply-To: <9915FC5ADAEC45D69273B593D3913BF8@RICHIEPC>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
 <9915FC5ADAEC45D69273B593D3913BF8@RICHIEPC>
Message-ID: <CAP92RBUAnO31kUiPBCj2OH_kUgGfdncvp818fSaMeKgtoU+g-A@mail.gmail.com>

Den s?n 1 sep. 2019 21:22 Richie Burnett <rburnett at richieburnett.co.uk>
skrev:

> One way to control the spectral broadening due to the amplitude modulation
> is obviously to band-limit the VCA's control signals.  I guess most VCA
> CV's
> have a faster attack than release, so it's mostly limiting the attack
> speed
> that we're talking about here.  High order LPFs applied to the VCA CVs
> give
> a more favourable trade-off between settling time and residual ripple.
>

Yes, and it's possible that a simple RC link after the ordinary envelope
follower is sufficient.

Another way to control the spectral broadening due to amplitude modulation
> in the VCA, and stop it bleeding into the adjacent bands, is to put the
> VCAs
> in-between the filter stages that make up each of the synthesis band
> filters.  This is what Roland did in their SVC-350 Vocoder.  It was
> probably
> done as much to filter out the PWM carrier frequency, but putting some of
> the vocoder's synthesis band filtering after the VCA helps to control
> out-of-band leakage caused by any fast VCA modulation.
>

Sennheiser VSM-201 did the same, IIRC.

On a related note, the conundrum I always face when thinking about Vocoder
> analysis and synthesis filter banks is how to deal with the bottom few
> bands...  The job of the analysis filter bank is to determine the spectral
> profile of the speech at any particular instant in time.  So ideally I
> want
> shed loads of closely spaced bands so that I get a fine-resolution picture
> of what the spectral profile is doing across the full speech range.  For
> instance, I might choose to use 24 bands spaced 1/4 octave exponentially
> to
> cover the 6 octave range from 80Hz up to 5.12 kHz.  This seems sensible as
> there probably aren't many vocal tract resonances outside this range that
> noticeably affect speech intelligibility.  However a problem arises with
> the
> bottom few bands.  All of the bands have the same Q and the same
> fractional
> bandwidth, however the actual bandwidth of the lower bands becomes only a
> handful of Hertz.  For example the bottom bands in my setup would be:
>
> 80-95Hz,
> 95-113Hz,
> 113Hz-135Hz,
> 135Hz-160Hz,
> 160-190Hz, *
> 190-226Hz,
> 226-269Hz,
> 269-320Hz,
> 320-381Hz, *
> 381-453Hz,
> 453-538Hz,
> 538-640Hz, *
> etc...
>
> This can lead to the frustrating situation where harmonics of the speech
> signal only fall into certain analysis bands at the low-frequency end of
> the
> speech range.  For example a female voice might easily have a fundamental
> frequency of 180Hz.  This would only put energy into the analysis bands
> centred around 180, 360, 540, 720 Hz, etc.  marked with the stars above,
> with nothing in the intervening bands.  This situation persists until
> eventually we get to a point where more than one harmonic of the voice
> signal starts to fit into each analysis band at some higher frequency.
> Then
> the holes in the analysis spectrum disappear.
>
> Clearly the analogue filter bank in this example is doing a poor job of
> estimating the spectral shaping of the vocal tract when the bands are made
> too narrow because they start to resolve the actual discrete spectral
> harmonics of the vocal signal.  This then leads to the situation where the
> output signal from the vocoder is very quiet unless the pitches of the
> voice
> and carrier inputs are related, so that harmonics of the speech and
> carrier
> inputs both land in the same frequency bands (>.<)  This isn't right.
>
> The problem is that I don't know the best way around this.


Frequency tracking of the voice signal, controlling a blending of the lower
bands in order to avoid the gaps?

I could make the
> analysis and synthesis bands wider and use less bands, but that seems a
> waste when modern DSPs have got enough grunt to run 40 bands easily.  Or I
> could make the lower frequency bands wider in an attempt to make sure that
> some harmonics of a given voice signal end up in every band at the lower
> end
> of the spectrum.  This is what Sennheiser seem to have done in at least
> one
> of their Vocoders


Did they make more models?

and it makes sense. However, I liked the idea of having

filter bands that are evenly spaced in octaves because I can then shift
> formants up or down easily by routing the outputs from analysis bands to
> adjacent synthesis bands across the audio range.  This isn't as simple if
> I
> alter the fractional bandwidths of the filters across the audio spectrum.
> The only other idea I had was to try to come up with some sort of
> interpolation algorithm to work around the "holes" in the spectral at the
> bottom end generated by the analysis filter bank which are particularly
> bad
> with voices that have a relatively high fundamental.
>
> I guess ultimately I need to accept that the analogue analysis filter-bank
> paradigm is a compromise.  Ultimately the best way to estimate the vocal
> tract resonances is probably to window one complete pitch period of the
> speech signal and then FFT it to get the spectrum.  That way you get a
> continuous spectrum, instead of a line spectrum out of the analysis
> process.
>
> Any thoughts and comments welcome.
>

Thanks for some interesting discussion.

/mr



>
> -Richie,
>
>
>
> -----Original Message-----
> From: Mattias Rickardsson
> Sent: Sunday, September 01, 2019 4:54 PM
> To: David G Dixon
> Cc: Synth DIY
> Subject: Re: [sdiy] vocoder filters
>
>
> The next level is to ponder on the unwanted higher-frequency AM effects
> from
> controlling a vocoder band VCA with the "best" (fastest) envelope
> follower,
> and whether a slower response could be more optimal. So much fun! :-)
>
> /mr
>
>
>
> Den l?r 31 aug. 2019 23:23David G Dixon <dixon at mail.ubc.ca> skrev:
>
>
> Not really.  It?s a full-wave rectifier followed by a standard LP filter
> stage tuned to about 1/4 of the expected incoming frequency followed by a
> notch filter tuned to twice the incoming frequency.  I also use a full
> wave
> rectifier instead of the normal half wave rectifier, because I figure this
> gives faster integration.  This is why the ripple is at twice the incoming
> frequency, and a notch filter knocks it out nicely.  Through the judicious
> choice of gain at the LP filter, the envelope follows the waveform tops
> more
> or less exactly, and comes up to full strength within two periods of the
> incoming waveform, with ripple which is inconsequential.  For a 10Vpp
> waveform coming in, the envelope rides at 5V, which will turn on my
> favored
> linearized 2164 VCA design to unity gain.
>
>
>
>
>
> From: David Moylan [mailto:dave at expeditionelectronics.com]
> Sent: Saturday, August 31, 2019 5:26 AM
> To: David G Dixon
> Cc: synth-diy at synth-diy.org
> Subject: Re: [sdiy] vocoder filters
>
>
>
>
>
>
>
> Curious about this envelope follower you mention. Trade secret?
>
>
>
>
>
>
>
> On Aug 31, 2019 03:48, David G Dixon <dixon at mail.ubc.ca> wrote:
>
>
>
> Well, I know that the higher-Q filters have a longer delay, so that they
> take longer to respond to the incoming waveform.  I?m thinking that a Q of
> about 3 is probably about right, and with that, only a 4-pole filter is
> required.
>
>
>
> I?ve got a nice design for an envelope follower which responds quickly and
> has little or no ripple, so that?s not a problem.
>
>
>
> On a related note, does anyone here have problems getting the Bode plotter
> in Multisim to work consistently?  I am finding with this simulation that
> sometimes if I change the component values, the Bode plotter doesn?t work
> at
> all.  Also, for some simulations, changing the component values doesn?t
> change the filter response at all.  Multisim is sure glitchy.  It?s very
> frustrating.  I can sometimes fix it if I erase all of the passive
> components and load new ones with the new values, rather than just
> changing
> them, but that sort of thing is just complete bullshit.  Multisim is a sad
> excuse for a professional program.  There must be something better out
> there
> (?).
>
>
>
>
>
> From: Paul Perry [mailto:paulfrancisperry at gmail.com]
> Sent: Friday, August 30, 2019 10:22 PM
> To: David G Dixon
> Subject: Re: [sdiy] vocoder filters
>
>
>
>
>
>
>
> I don't think there is a "right" answer. To my mind, it depends on what
> one
> wants to do with the unit. Think about what will happen when a single
> swept
> tone is used to modify white noise. The low pass filter on the VCAs
> probably
> has a significant effect as well.
>
>
>
> paul perry Melbourne Australia
>
>
>
>
>
>
>
> On Sat, 31 Aug 2019 at 14:50, David G Dixon <dixon at mail.ubc.ca> wrote:
>
>
>
> Well, I think I might have answered my own question.  Looking again at the
> JH Living Vocoder, since Jurgen Haible?s filter responses overlap at about
> the 8dB mark, it really should not matter at all what?s going on around
> the
> skirt of the response, and higher-Q filters with two 2-pole stages should
> give very similar results to low-Q filters with four 4-pole stages (and be
> much much cheaper to build).
>
>
>
> I?d still appreciate if anyone has any specific insights into this
> problem.
> Cheers.
>
>
>
>
>
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of
> David
> G Dixon
> Sent: Friday, August 30, 2019 9:05 PM
> To: synth-diy at synth-diy.org
> Subject: [sdiy] vocoder filters
>
>
>
>
>
> Hey SDIY Team!
>
>
>
> I?m thinking about building a vocoder, and I have a general question about
> the bandpass filters.
>
>
>
> I?ve looked at Jurgen Haible?s Living Vocoder, and he used 8-pole filters
> with low Q.  These give a reasonably broad band with fairly steep slopes.
> He makes the filters from two pairs of LP and HP.
>
>
>
> I was thinking about using BP filter sections, but just 4-pole, and with
> higher Q (around 10).  This gives a somewhat narrower band, and the slope
> is
> steep near the corner, but fairly shallow around the skirt.  This idea
> uses
> a lot fewer components (about half as many).
>
>
>
> What I?m asking is, does anybody here have any insight into what the
>  ?proper? approach to vocoder filters would be?  What is the design goal?
> Do you want significant overlap from one band to the next, or should they
> be
> fairly distinct?  I guess I?m just looking for some general guidelines and
> conventional wisdom.
>
>
>
> Cheers,
>
> Dave Dixon
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
>
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
>
> Virus-free. www.avg.com
>
>
>
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
>
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From ben at stuyts.nl  Mon Sep  2 00:05:01 2019
From: ben at stuyts.nl (Ben Stuyts)
Date: Mon, 2 Sep 2019 00:05:01 +0200
Subject: [sdiy] vocoder filters
In-Reply-To: <C2A0703E5C5E448FA5A1224C0C4D7B04@david78c70950b>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
 <C2A0703E5C5E448FA5A1224C0C4D7B04@david78c70950b>
Message-ID: <64C05EE3-02A4-4088-BEAB-7163E04B684D@stuyts.nl>



> On 1 Sep 2019, at 20:28, David G Dixon <dixon at mail.ubc.ca> wrote:
> 
> My original idea was to make a vocoder with 88 channels ? one for each semitone of the piano range ? with resonating filters that would ring out with a sine wave when excited.  In this way, the device would ?sing? some ethereal version of whatever music was fed to it, in tune.  Maybe, with single opamp filters, this is doable.

Different kind of thing, but this reminds me of a very nice audio plugin reverb I have from PSP-Audio. It?s called Pianoverb, an I believe there is a free version. It basically sounds like the soundboard of a piano with the dampers lifted off the strings. The strings then resonate with the music you play through it.

Ben

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From dixon at mail.ubc.ca  Mon Sep  2 00:18:15 2019
From: dixon at mail.ubc.ca (David G Dixon)
Date: Sun, 1 Sep 2019 15:18:15 -0700
Subject: [sdiy] vocoder filters
In-Reply-To: <64C05EE3-02A4-4088-BEAB-7163E04B684D@stuyts.nl>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
 <C2A0703E5C5E448FA5A1224C0C4D7B04@david78c70950b>
 <64C05EE3-02A4-4088-BEAB-7163E04B684D@stuyts.nl>
Message-ID: <209D37D9E89E49CBA354AFB4C7C05329@david78c70950b>

Cool.  This 88-channel vocoder thingy may sound somewhat similar, especially
if the filters all ring a little.

 

In other news, thanks everybody for an interesting and informative
discussion.  There's a lot of food here for thought, especially from Richie
regarding spectral analysis and harmonics.  Good stuff!  I'm sure I'll be
knee deep in worms once I actually open the can and start building.

 

  _____  

From: Ben Stuyts [mailto:ben at stuyts.nl] 
Sent: Sunday, September 01, 2019 3:05 PM
To: David G Dixon
Cc: Mattias Rickardsson; Synth DIY
Subject: Re: [sdiy] vocoder filters

 

 





On 1 Sep 2019, at 20:28, David G Dixon <dixon at mail.ubc.ca> wrote:

 

My original idea was to make a vocoder with 88 channels - one for each
semitone of the piano range - with resonating filters that would ring out
with a sine wave when excited.  In this way, the device would "sing" some
ethereal version of whatever music was fed to it, in tune.  Maybe, with
single opamp filters, this is doable.

 

Different kind of thing, but this reminds me of a very nice audio plugin
reverb I have from PSP-Audio. It's called Pianoverb, an I believe there is a
free version. It basically sounds like the soundboard of a piano with the
dampers lifted off the strings. The strings then resonate with the music you
play through it.

 

Ben

 

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From dixon at mail.ubc.ca  Mon Sep  2 00:22:31 2019
From: dixon at mail.ubc.ca (David G Dixon)
Date: Sun, 1 Sep 2019 15:22:31 -0700
Subject: [sdiy] vocoder filters
In-Reply-To: <64C05EE3-02A4-4088-BEAB-7163E04B684D@stuyts.nl>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
 <C2A0703E5C5E448FA5A1224C0C4D7B04@david78c70950b>
 <64C05EE3-02A4-4088-BEAB-7163E04B684D@stuyts.nl>
Message-ID: <D194E3AA78B94A7CAB535374055B77D9@david78c70950b>

Also, I just wanted to mention that I have listened to some of the many
clips of the MFOS vocoder posted by the late, great Ray Wilson, and. I don't
find the speech to be very intelligible.  I would have to do better than
that to be satisfied with my efforts.  The JH one was pretty intelligible
(notwithstanding the thick German accent - he may have been speaking German
for part of it.?).

 

I'll also look at some of the classic vocoder schematics.  I"ve got the
Roland VP-330 to study - that one sounds pretty sweet.  I don't just want to
clone something, though - that's definitely not my style.

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From didierleplae at yahoo.com  Mon Sep  2 00:34:18 2019
From: didierleplae at yahoo.com (Didier Leplae)
Date: Sun, 1 Sep 2019 17:34:18 -0500
Subject: [sdiy] vocoder filters
In-Reply-To: <D194E3AA78B94A7CAB535374055B77D9@david78c70950b>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
 <C2A0703E5C5E448FA5A1224C0C4D7B04@david78c70950b>
 <64C05EE3-02A4-4088-BEAB-7163E04B684D@stuyts.nl>
 <D194E3AA78B94A7CAB535374055B77D9@david78c70950b>
Message-ID: <A7ED77EF-655B-487C-B37E-979C96DA6DEE@yahoo.com>

I love this talking piano device and have wondered how it works. I imagine it must have similarities to a vocoder in how it works. Does anybody know?
It would be super interesting to have a plugin that translates speech into midi like this:

https://m.youtube.com/watch?v=muCPjK4nGY4


> On Sep 1, 2019, at 5:22 PM, David G Dixon <dixon at mail.ubc.ca> wrote:
> 
> Also, I just wanted to mention that I have listened to some of the many clips of the MFOS vocoder posted by the late, great Ray Wilson, and? I don?t find the speech to be very intelligible.  I would have to do better than that to be satisfied with my efforts.  The JH one was pretty intelligible (notwithstanding the thick German accent ? he may have been speaking German for part of it??).
>  
> I?ll also look at some of the classic vocoder schematics.  I?ve got the Roland VP-330 to study ? that one sounds pretty sweet.  I don?t just want to clone something, though ? that?s definitely not my style.
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
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From bah13 at cornell.edu  Mon Sep  2 00:44:54 2019
From: bah13 at cornell.edu (Bernard Arthur Hutchins, Jr)
Date: Sun, 1 Sep 2019 22:44:54 +0000
Subject: [sdiy] vocoder filters
Message-ID: <DM6PR04MB6043F4951CCA655AFDF03F90BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>

The general set of vocoder problems mentioned here yield to a specific digital approach.

First, the need for MANY (topographically similar) filters with unknown or uncertain parameters is an obvious job for programming.

Second, obviously, the equivalent of filtering can be done by taking an FFT (analysis), custom weighting the frequency domain description (the dynamics) and inverting the thusly modified FFT (synthesis).

Thirdly, since the FFT frequencies are equally spaced in Hz (requiring huge FFT sizes) the FFT is NOT well-suited to the audio/speech problem. Instead, look at the well-studied approach of MULTI-RATE DSP where lower rates at lower frequencies are used.  (It?s magic).  Things like ?perfect-reconstruction filers?.  See: P.P. Vaidyanathan ?Multirate Systems and Filter Banks? (Prentice-Hall, 1993) and N.J. Fliege, ?Multirate Digital Signal Processing: Multirate Systems, Filter Banks, Wavelets? (Wiley 1994).

A simple introductfion: http://electronotes.netfirms.com/AN358.pdf

But first of all ? What are you hoping to accomplish?


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From dixon at mail.ubc.ca  Mon Sep  2 01:11:46 2019
From: dixon at mail.ubc.ca (David G Dixon)
Date: Sun, 1 Sep 2019 16:11:46 -0700
Subject: [sdiy] vocoder filters
In-Reply-To: <DM6PR04MB6043F4951CCA655AFDF03F90BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
References: <DM6PR04MB6043F4951CCA655AFDF03F90BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
Message-ID: <12196EE9D7D1405680459D1D1D45945A@david78c70950b>

What do I hope to accomplish?  Not sure.  Mostly to have fun getting stuck
into another stupidly large electronics project.  I don't do digital -
coding seems too much like work (I'm an engineering professor, and I
specialized in mathematical models in my academic work, before I saw the
light and started developing new processes instead - for extraction of
copper from ores and concentrates, in case you're curious).

 

  _____  

From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of
Bernard Arthur Hutchins, Jr
Sent: Sunday, September 01, 2019 3:45 PM
To: synth-diy at synth-diy.org
Cc: Bernard Arthur Hutchins, Jr
Subject: Re: [sdiy] vocoder filters

 

The general set of vocoder problems mentioned here yield to a specific
digital approach.

 

First, the need for MANY (topographically similar) filters with unknown or
uncertain parameters is an obvious job for programming.

 

Second, obviously, the equivalent of filtering can be done by taking an FFT
(analysis), custom weighting the frequency domain description (the dynamics)
and inverting the thusly modified FFT (synthesis).

 

Thirdly, since the FFT frequencies are equally spaced in Hz (requiring huge
FFT sizes) the FFT is NOT well-suited to the audio/speech problem. Instead,
look at the well-studied approach of MULTI-RATE DSP where lower rates at
lower frequencies are used.  (It's magic).  Things like
"perfect-reconstruction filers".  See: P.P. Vaidyanathan "Multirate Systems
and Filter Banks" (Prentice-Hall, 1993) and N.J. Fliege, "Multirate Digital
Signal Processing: Multirate Systems, Filter Banks, Wavelets" (Wiley 1994).

 

A simple introductfion:  <http://electronotes.netfirms.com/AN358.pdf>
http://electronotes.netfirms.com/AN358.pdf

 

But first of all - What are you hoping to accomplish?   

 

 

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From pete.hartman at gmail.com  Mon Sep  2 01:38:21 2019
From: pete.hartman at gmail.com (Pete Hartman)
Date: Sun, 1 Sep 2019 18:38:21 -0500
Subject: [sdiy] vocoder filters
In-Reply-To: <D194E3AA78B94A7CAB535374055B77D9@david78c70950b>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
 <C2A0703E5C5E448FA5A1224C0C4D7B04@david78c70950b>
 <64C05EE3-02A4-4088-BEAB-7163E04B684D@stuyts.nl>
 <D194E3AA78B94A7CAB535374055B77D9@david78c70950b>
Message-ID: <CACodTR-+FTszkx67qWeL0TBZkYmFmFVmc74c19=yXfWumWdaeg@mail.gmail.com>

On Sun, Sep 1, 2019 at 5:25 PM David G Dixon <dixon at mail.ubc.ca> wrote:

> Also, I just wanted to mention that I have listened to some of the many
> clips of the MFOS vocoder posted by the late, great Ray Wilson, and? I
> don?t find the speech to be very intelligible.  I would have to do better
> than that to be satisfied with my efforts.  The JH one was pretty
> intelligible (notwithstanding the thick German accent ? he may have been
> speaking German for part of it??).
>
>
>
Yeah, when you mentioned looking at Ray's vocoder, I debated piping up and
noting that I didn't find it very clear.  Pulling a couple design aspects
out of it for an experiment sounds like it could yield interesting results
anyway though.
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From okvern at ix.netcom.com  Mon Sep  2 02:05:19 2019
From: okvern at ix.netcom.com (Olav Martin Kvern)
Date: Sun, 1 Sep 2019 17:05:19 -0700
Subject: [sdiy] Patchell Vocal Filter board [was] Re:  vocoder filters
In-Reply-To: <CABbX2d-BOoG8ZO=0UfRXpWm6EK=tPhZUEK5ZzT4dErOeFeQJqA@mail.gmail.com>
References: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
 <CABbX2d-BOoG8ZO=0UfRXpWm6EK=tPhZUEK5ZzT4dErOeFeQJqA@mail.gmail.com>
Message-ID: <cc2062a4-c70d-7e22-ea89-136ad8cc3d63@ix.netcom.com>

bbob wrote: "speaking of back in the day... don't forget Jim Patchell's vocal filter (http://www.noniandjim.com/Jim/synthmodules/vocalfilter.html).  check out the picture of the PCB - to me it is an inspiration and a thing of beauty..."

I have one of these boards that I am never going to get to. I was literally about to drop it off at an electronics recycling place.

If you want it, I'd be happy to ship it to you (free shipping for US addresses--if you're elsewhere, we can work something out). Drop me a line off-list.

Thanks,

Ole


From okvern at ix.netcom.com  Mon Sep  2 02:51:21 2019
From: okvern at ix.netcom.com (Olav Martin Kvern)
Date: Sun, 1 Sep 2019 17:51:21 -0700
Subject: [sdiy] Patchell Vocal Filter board [was] Re: vocoder filters
In-Reply-To: <cc2062a4-c70d-7e22-ea89-136ad8cc3d63@ix.netcom.com>
References: <DM6PR04MB60433C1658514427B4CBEB59BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
 <CABbX2d-BOoG8ZO=0UfRXpWm6EK=tPhZUEK5ZzT4dErOeFeQJqA@mail.gmail.com>
 <cc2062a4-c70d-7e22-ea89-136ad8cc3d63@ix.netcom.com>
Message-ID: <db0e8005-ff0e-2352-23bc-d6641683cfa0@ix.netcom.com>

Colleagues,

Board has been claimed. I'll have to see what else I've got lying around....:-)

Thanks,

Ole

On 9/1/19 5:05 PM, Olav Martin Kvern wrote:
> bbob wrote: "speaking of back in the day... don't forget Jim Patchell's vocal filter (http://www.noniandjim.com/Jim/synthmodules/vocalfilter.html).? check out the picture of the PCB - to me it is an inspiration and a thing of beauty..."
> 
> I have one of these boards that I am never going to get to. I was literally about to drop it off at an electronics recycling place.
> 
> If you want it, I'd be happy to ship it to you (free shipping for US addresses--if you're elsewhere, we can work something out). Drop me a line off-list.
> 
> Thanks,
> 
> Ole
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> 


From bah13 at cornell.edu  Mon Sep  2 04:47:46 2019
From: bah13 at cornell.edu (Bernard Arthur Hutchins, Jr)
Date: Mon, 2 Sep 2019 02:47:46 +0000
Subject: [sdiy] vocoder filters
Message-ID: <DM6PR04MB6043AA35A44F4D2E96232D5FBCBE0@DM6PR04MB6043.namprd04.prod.outlook.com>

My asking what anyone hoped to accomplish with something dubbed a ?Vocoder? was meant to suggest that anyone undertaking such a task (particularly if doing it in analog!) needs to have studied ?prior art? and to state a plan going forward.  Presumably the goal is NOT to achieve a communication channel, or to reproduce a (classic ? 60 year old) Vocal Encoder/Decoder for a quirky ?robot voice?.

I would hope the model was rather an attempt to capture the spectral shape of a segment of speech or singing (most likely of successive ?frames? of perhaps 50 msec each) and impose this shape on an entirely new (artificial) excitation.  For example, you might in two second say: ?Dogs and cats each hates the other? and analyze the resulting 40 frames into a sequence of formants - ?40 frequency responses?.  If we HAD also analyzed for the original excitation (like pitch - not just the formants), and used this to excite the filter profiles in sequence, we might have some garbled notion of cats and dogs.  Played back with some synthetic substitute excitation (perhaps a saw or noise) we would hope for some vague feeling of a vocal origin capturing our interest if not imparting any verbal information.  But presumably we were not intending to RECOVER speech, so the achievement of a NEW vocal-like impression is what we wanted.

This experiment (and use) is at least 45 years old.  Better name than vocoder?

- Bernie

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From magnus at rubidium.se  Mon Sep  2 08:24:40 2019
From: magnus at rubidium.se (Magnus Danielson)
Date: Mon, 2 Sep 2019 08:24:40 +0200
Subject: [sdiy] vocoder filters
In-Reply-To: <A31B78DEC0A64298AE8ACA5A1D3F182D@david78c70950b>
References: <A31B78DEC0A64298AE8ACA5A1D3F182D@david78c70950b>
Message-ID: <6abe2880-ffeb-d65b-f510-e4d121324427@rubidium.se>

Dear David,

Many other vocoders used higher Q setups, and J?rgen and I agreed that
you need to avoid that. The reason is that higher Q gets you into higher
group delay, making the filter more sluggish to respond and rings longer
after the end of a sound. It also causes different time-shifts between
bands to become bigger than if you use low Q.

J?rgen was inspired by the EMS3000 vocoder until I sent him the EMS5000
manual and schematic, which derailed the project a little. :)

So, it is not recommended to go for higher Q, and I think you get why.

Cheers,
Magnus

On 2019-08-31 06:05, David G Dixon wrote:
>
> Hey SDIY Team!
>
> ?
>
> I?m thinking about building a vocoder, and I have a general question
> about the bandpass filters.
>
> ?
>
> I?ve looked at Jurgen Haible?s Living Vocoder, and he used 8-pole
> filters with low Q. ?These give a reasonably broad band with fairly
> steep slopes.? He makes the filters from two pairs of LP and HP.
>
> ?
>
> I was thinking about using BP filter sections, but just 4-pole, and
> with higher Q (around 10). ?This gives a somewhat narrower band, and
> the slope is steep near the corner, but fairly shallow around the
> skirt.? This idea uses a lot fewer components (about half as many).
>
> ?
>
> What I?m asking is, does anybody here have any insight into what the
> ?proper? approach to vocoder filters would be? ?What is the design
> goal?? Do you want significant overlap from one band to the next, or
> should they be fairly distinct? ?I guess I?m just looking for some
> general guidelines and conventional wisdom.
>
> ?
>
> Cheers,
>
> Dave Dixon
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
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From rburnett at richieburnett.co.uk  Mon Sep  2 11:43:09 2019
From: rburnett at richieburnett.co.uk (rburnett at richieburnett.co.uk)
Date: Mon, 02 Sep 2019 10:43:09 +0100
Subject: [sdiy] vocoder filters
In-Reply-To: <CAP92RBUAnO31kUiPBCj2OH_kUgGfdncvp818fSaMeKgtoU+g-A@mail.gmail.com>
References: <98C13EFF36F542389BE549CE45C59BEF@david78c70950b>
 <ddf11fee-0b70-4f52-80d3-a96b4c98c6b9@email.android.com>
 <62CB86078C824AC689D370C0211065B3@david78c70950b>
 <CAP92RBU5aNGprjVmdwe9tzbDHAh+bS=rjvNQAkOPDW0ZW27zJg@mail.gmail.com>
 <9915FC5ADAEC45D69273B593D3913BF8@RICHIEPC>
 <CAP92RBUAnO31kUiPBCj2OH_kUgGfdncvp818fSaMeKgtoU+g-A@mail.gmail.com>
Message-ID: <2c8e63a158802dc4f152379e3efb90ea@richieburnett.co.uk>

> Frequency tracking of the voice signal, controlling a blending of the
> lower bands in order to avoid the gaps?

It is interesting that you mention frequency tracking.  I had originally 
wanted to include pitch detection on the incoming voice signal for a 
couple of reasons.  Firstly, if you know the pitch of the incoming vocal 
signal, and you also know the spectrum, you can re-synthesise the voice 
with pitch and/or formants shifted by the Vocoder for harmonizer type 
effects.  Secondly, if you know the pitch period from ASDF or 
autocorrelation, you can easily remove the tonal "voiced" spectral lines 
of the original voice signal with a comb filter to leave a residual 
"un-voiced" noise-like component.  This residual signal could then 
either be routed around the Vocoder and mixed into the final output to 
improve intelligibility, or it could be analysed by a separate filter 
bank to process spectral shaping of an additional un-voiced noise-like 
carrier signal.  But efficient robust pitch tracking isn't trivial to 
achieve though, so it might have needed an additional dsPIC running 
alongside the one doing the Vocoder filter banks.

>> This is what Sennheiser seem to have done in at
>> least one
>> of their Vocoders
> 
> Did they make more models?

To be honest I don't know.  I was giving them the benefit of the doubt 
;-)  I thought I read somewhere that they made specials for Daft Punk or 
something.

> Thanks for some interesting discussion.

No worries.  They were just some thoughts that were left in my mind from 
my own Vocoder experimenting.

-Richie,


From rburnett at richieburnett.co.uk  Mon Sep  2 12:04:53 2019
From: rburnett at richieburnett.co.uk (rburnett at richieburnett.co.uk)
Date: Mon, 02 Sep 2019 11:04:53 +0100
Subject: [sdiy] vocoder filters
In-Reply-To: <DM6PR04MB6043F4951CCA655AFDF03F90BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
References: <DM6PR04MB6043F4951CCA655AFDF03F90BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
Message-ID: <799f9f69fc7f430d46c7acc5616b69d2@richieburnett.co.uk>

Multi-rate processing is what made it possible to run 160 biquad filters 
simultaneously on my 30MHz dsPIC.  The filter bands for the top two 
octaves were run at the full sample rate, and then the bands for 
successively lower octaves were each run at half of the previous sample 
rate.  This gives a huge saving in CPU load across the full audio band, 
and it also lets you re-use the same sets of filter coefficients for the 
IIR filters at each new sample rate!  It was a bit of a pain on the 
synthesis side though because the outputs from all of the different 
filters running at different sample rates all had to be interpolated 
back up to the full output sample rate (>.<)  The thing that I found 
tricky was keeping track of all of the delays in the down-sampling and 
the up-sampling processes for each octave, so that the outputs from all 
of the filter bands were properly time-aligned when mixed together at 
the output!

Multi-rate DSP definitely can seem like a magic bullet.  It is amazing 
that it is more efficient doing all of the decimation, running things at 
multiple sample rates, and then interpolating and putting it all back 
together again, than it is to just run all of the filters at the full 
rate.  In fact multi-rate DSP can be the difference between something 
that is realisable on a given piece of hardware and something that is 
not realisable.

-Richie,

BTW, the talking piano video is terrifying!


On 2019-09-01 23:44, Bernard Arthur Hutchins, Jr wrote:
> The general set of vocoder problems mentioned here yield to a specific
> digital approach.
> 
> First, the need for MANY (topographically similar) filters with
> unknown or uncertain parameters is an obvious job for programming.
> 
> Second, obviously, the equivalent of filtering can be done by taking
> an FFT (analysis), custom weighting the frequency domain description
> (the dynamics) and inverting the thusly modified FFT (synthesis).
> 
> Thirdly, since the FFT frequencies are equally spaced in Hz (requiring
> huge FFT sizes) the FFT is NOT well-suited to the audio/speech
> problem. Instead, look at the well-studied approach of MULTI-RATE DSP
> where lower rates at lower frequencies are used.  (It?s magic).
> Things like ?perfect-reconstruction filers?.  See: P.P.
> Vaidyanathan ?Multirate Systems and Filter Banks? (Prentice-Hall,
> 1993) and N.J. Fliege, ?Multirate Digital Signal Processing:
> Multirate Systems, Filter Banks, Wavelets? (Wiley 1994).
> 
> A simple introductfion: http://electronotes.netfirms.com/AN358.pdf
> 
> But first of all ? What are you hoping to accomplish?
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy


From sleepy_dog at gmx.de  Tue Sep  3 02:04:47 2019
From: sleepy_dog at gmx.de (sleepy_dog at gmx.de)
Date: Tue, 3 Sep 2019 02:04:47 +0200
Subject: [sdiy] OT: Guitar FX - Loopers & prices - what magic is in there?
Message-ID: <9ec7df10-1bea-6a5b-52f2-8848b0c577af@gmx.de>

Hello list,

I recently looked at some of those loopers that are apparently
especially popupar among guitarists, but also other instrumentalists.
I was also more specifically looking for one with +48V XLR input to use
it for both, instant feedback for practising singing without messing
with computer software, and also actually practicing instruments /
jamming, experimenting. The handling (or rather, "footling"?) of the
looper for this "sing a line, step on it, hear it" seems even simpler /
less distracting than just using my litte old portable recorder - nice
for concentrating on self monitoring/correction in this regard.

So I found e.g. the Boss RC30, which has 2 foot switches, a display, a
few more small buttons, evidently some RAM and some not too complicated
DSP stuff.
Costs about 200 $.

Or the RC300, 3x or so as wide, more foot switches.
This costs ~ 500 $ and doesn't even have stuff like time stretching,
which *cough* pedals for ~ 1000 $ I've seen have.


Now, in my hobbyist imagination, who has done some projects roughly
involving the things I imagine to be involved here, but not exatcly the
type of product, it seems like this stuff should neither be exactly
rocket science, the R&D shouldn't be too tough on those, nor special
super duper hardware to make it happen (also hinted at the fact that
some of the products are out there for ~ 10 years, unchanged).
While I see that the rugged cases & switches do cost something - 500 or
more? Get real. My age old laptop which cost less than that back than
could do a lot more than what those things do, apart from being stomped
on hard and still work.

What am I missing, what magic is in there to justify those kinda prices?
Let's not forget that those aren't boutique synth modules, but rather
mass produced pedals for one of the most popular musical instruments.

I almost was about to slap something together involving a Raspberry Pi
Z, an audio codec, and some cheap thomann stackable foot swtiches.
But that'll probably result in not-so-low latency with the Linux audio
stack in the background :)

I will probably bite the bullet for the RC 30 for ~ 200, one of the few
smaller ones with XLR mic in, albeit some reported usability issues and
paying also for some absolutely pointless built-in effects... (FX are
cool, just not those)

- Steve





From bah13 at cornell.edu  Tue Sep  3 05:53:38 2019
From: bah13 at cornell.edu (Bernard Arthur Hutchins, Jr)
Date: Tue, 3 Sep 2019 03:53:38 +0000
Subject: [sdiy] vocoder filters
In-Reply-To: <DM6PR04MB604344CE551204594A090DDDBCB90@DM6PR04MB6043.namprd04.prod.outlook.com>
References: <DM6PR04MB604344CE551204594A090DDDBCB90@DM6PR04MB6043.namprd04.prod.outlook.com>
Message-ID: <DM6PR04MB6043F14172E626482B78ACE7BCB90@DM6PR04MB6043.namprd04.prod.outlook.com>


I have posted (links below) on my Electronotes site the full articles (supplementing the AES paper):   (EN102) on the vocal-effects waveform animator and (EN87) the Multi-Phase Waveform Animator along with two additions (one simplification ? for the person threatening to build one!) to the presentation of that second design. The MPWA is certainly cheap and powerful ? perhaps our most popular design.


http://electronotes.netfirms.com/EN87-1-11.pdf

http://electronotes.netfirms.com/EN102.pdf

http://electronotes.netfirms.com/EN108-6-9.pdf

http://electronotes.netfirms.com/AN73.pdf
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From elmacaco at hotmail.com  Tue Sep  3 08:08:09 2019
From: elmacaco at hotmail.com (el macaco)
Date: Tue, 3 Sep 2019 06:08:09 +0000
Subject: [sdiy] vocoder filters
In-Reply-To: <799f9f69fc7f430d46c7acc5616b69d2@richieburnett.co.uk>
References: <DM6PR04MB6043F4951CCA655AFDF03F90BCBF0@DM6PR04MB6043.namprd04.prod.outlook.com>
 <799f9f69fc7f430d46c7acc5616b69d2@richieburnett.co.uk>
Message-ID: <MWHPR19MB1037C8764D9491D630AFA47FC4B90@MWHPR19MB1037.namprd19.prod.outlook.com>

What about the abuchea spectral processor? Old and new? Might have some ideas...

> On Sep 2, 2019, at 5:04 AM, rburnett at richieburnett.co.uk wrote:
> 
> Multi-rate processing is what made it possible to run 160 biquad filters simultaneously on my 30MHz dsPIC.  The filter bands for the top two octaves were run at the full sample rate, and then the bands for successively lower octaves were each run at half of the previous sample rate.  This gives a huge saving in CPU load across the full audio band, and it also lets you re-use the same sets of filter coefficients for the IIR filters at each new sample rate!  It was a bit of a pain on the synthesis side though because the outputs from all of the different filters running at different sample rates all had to be interpolated back up to the full output sample rate (>.<)  The thing that I found tricky was keeping track of all of the delays in the down-sampling and the up-sampling processes for each octave, so that the outputs from all of the filter bands were properly time-aligned when mixed together at the output!
> 
> Multi-rate DSP definitely can seem like a magic bullet.  It is amazing that it is more efficient doing all of the decimation, running things at multiple sample rates, and then interpolating and putting it all back together again, than it is to just run all of the filters at the full rate.  In fact multi-rate DSP can be the difference between something that is realisable on a given piece of hardware and something that is not realisable.
> 
> -Richie,
> 
> BTW, the talking piano video is terrifying!
> 
> 
>> On 2019-09-01 23:44, Bernard Arthur Hutchins, Jr wrote:
>> The general set of vocoder problems mentioned here yield to a specific
>> digital approach.
>> First, the need for MANY (topographically similar) filters with
>> unknown or uncertain parameters is an obvious job for programming.
>> Second, obviously, the equivalent of filtering can be done by taking
>> an FFT (analysis), custom weighting the frequency domain description
>> (the dynamics) and inverting the thusly modified FFT (synthesis).
>> Thirdly, since the FFT frequencies are equally spaced in Hz (requiring
>> huge FFT sizes) the FFT is NOT well-suited to the audio/speech
>> problem. Instead, look at the well-studied approach of MULTI-RATE DSP
>> where lower rates at lower frequencies are used.  (It?s magic).
>> Things like ?perfect-reconstruction filers?.  See: P.P.
>> Vaidyanathan ?Multirate Systems and Filter Banks? (Prentice-Hall,
>> 1993) and N.J. Fliege, ?Multirate Digital Signal Processing:
>> Multirate Systems, Filter Banks, Wavelets? (Wiley 1994).
>> A simple introductfion: http://electronotes.netfirms.com/AN358.pdf
>> But first of all ? What are you hoping to accomplish?
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy



From dixon at mail.ubc.ca  Wed Sep  4 01:35:31 2019
From: dixon at mail.ubc.ca (David G Dixon)
Date: Tue, 3 Sep 2019 16:35:31 -0700
Subject: [sdiy] vocoder filters
In-Reply-To: <6abe2880-ffeb-d65b-f510-e4d121324427@rubidium.se>
References: <A31B78DEC0A64298AE8ACA5A1D3F182D@david78c70950b>
 <6abe2880-ffeb-d65b-f510-e4d121324427@rubidium.se>
Message-ID: <C283E962064D42B0881A047F9F3E8995@david78c70950b>

So, today I have done some simulations, and have discovered that I can
replicate the frequency response and delay characteristics of Jurgen
Haible?s 8-pole (4-stage) BP filters with my own 4-pole (2-stage) BP filters
with a Q of about 3 (for each stage).  The output frequency responses look
virtually identical, and given an input sine wave (or square wave) at the
filter?s corner frequency, the output signal is up to full amplitude within
5 or 6 periods, for both filters.  When the input signal is turned off, the
ringing characteristics of both filters are also essentially identical, with
the signal dying away within 5 or 6 periods.

 

>From this, I conclude that I can get the same results that Jurgen Haible got
with about half of the filter hardware, as I suspected.  This is nice, since
I have already laid out and built a PCB with 12 of these 4-pole BP filters
on it for a fixed filter bank, and I can use the exact same layout for the
vocoder.

 

  _____  

From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Magnus
Danielson
Sent: Sunday, September 01, 2019 11:25 PM
To: synth-diy at synth-diy.org
Subject: Re: [sdiy] vocoder filters

 

Dear David,

Many other vocoders used higher Q setups, and J?rgen and I agreed that you
need to avoid that. The reason is that higher Q gets you into higher group
delay, making the filter more sluggish to respond and rings longer after the
end of a sound. It also causes different time-shifts between bands to become
bigger than if you use low Q.

J?rgen was inspired by the EMS3000 vocoder until I sent him the EMS5000
manual and schematic, which derailed the project a little. :)

So, it is not recommended to go for higher Q, and I think you get why.

Cheers,
Magnus

On 2019-08-31 06:05, David G Dixon wrote:

Hey SDIY Team!

 

I?m thinking about building a vocoder, and I have a general question about
the bandpass filters.

 

I?ve looked at Jurgen Haible?s Living Vocoder, and he used 8-pole filters
with low Q.  These give a reasonably broad band with fairly steep slopes.
He makes the filters from two pairs of LP and HP.

 

I was thinking about using BP filter sections, but just 4-pole, and with
higher Q (around 10).  This gives a somewhat narrower band, and the slope is
steep near the corner, but fairly shallow around the skirt.  This idea uses
a lot fewer components (about half as many).

 

What I?m asking is, does anybody here have any insight into what the
?proper? approach to vocoder filters would be?  What is the design goal?  Do
you want significant overlap from one band to the next, or should they be
fairly distinct?  I guess I?m just looking for some general guidelines and
conventional wisdom.

 

Cheers,

Dave Dixon






_______________________________________________
Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy

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From bah13 at cornell.edu  Wed Sep  4 05:40:45 2019
From: bah13 at cornell.edu (Bernard Arthur Hutchins, Jr)
Date: Wed, 4 Sep 2019 03:40:45 +0000
Subject: [sdiy] vocoder filters
Message-ID: <BN8PR04MB6036C0A583110B460F91D16ABCB80@BN8PR04MB6036.namprd04.prod.outlook.com>





Magnus ?

I think we would agree that there may be reasons for considering bandpass responses of order greater than 2 ? but getting a higher Q (sharper peak) is not likely to be one of them.  Usually the sharper Q is obtainable just by increasing the performance Q of the second-order.  It?s not like the case with low-pass where extra poles give you a sharper roll-off rate JUST BEYOND the corner (like 24 db instead of 12).  With a high-Q BP, the ?skirts? begin well after the response is well below the peak.

If you DO want sharper ?skirts? (say 12 db on each side of the peak instead of the 2nd-order 6db on each side), then a cascading of identical BPs is the ticket. The Q increases in such cases, but distressingly slowly- if I recall. So it is probably not even a good way to sharpen a BP.

The real use of (and meanings of) higher-order BP is to achieve a flatter passband.  The poles are slightly offsets so that when we move away from one, with a declining gain, the next pole takes over.  This is so-called ?stagger-tuning? - a difficult design.



But the design is easy if one uses a lowpass-to-bandpass transformation for Butterworth or Chebyshev:

  http://electronotes.netfirms.com/AN336.pdf

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From rsdio at audiobanshee.com  Thu Sep  5 09:48:34 2019
From: rsdio at audiobanshee.com (rsdio at audiobanshee.com)
Date: Thu, 5 Sep 2019 00:48:34 -0700
Subject: [sdiy] OT: Guitar FX - Loopers & prices - what magic is in
 there?
In-Reply-To: <9ec7df10-1bea-6a5b-52f2-8848b0c577af@gmx.de>
References: <9ec7df10-1bea-6a5b-52f2-8848b0c577af@gmx.de>
Message-ID: <F592D565-60F1-4AA5-B621-620F158B062D@audiobanshee.com>

Steve,

Nothing is priced based on component cost. Price comes from supply and demand.

Of course, nobody will price gear *below* the cost of the components because that?s an unsustainable loss. The only exception is if they?re dumping old stock that?s already a loss - better to sell at a loss then than never sell at all, and better to stay in business long enough that the losses are offset by profits.

On the flip side, though, there?s no upper limit on prices so long as they?re above the component costs. The only ?justification? needed is that people are willing to pay. The catch is that any company who tries to sell a product for too much will be surprised by the Behringers of the world who are willing to make a product as cheaply as possible and get closer to the cost of the components than their competitors. Nobody can predict the future with 100% certainty, and there?s always the risk that what gets manufactured will not ever sell, at least not the entire inventory.

Basically, it all comes down to you. If you don?t think the full set of features is worth $1,000 then you can either build it yourself or buy a model with fewer features. Maybe you could even do without.

You?re right that a maker Pi plus Linux would have latency, but you could learn real-time (RTOS or other) programming to avoid the latency. You might even have fun. I do. But unless you have experience with mechanical engineering, you might stomp on your baby a little too hard and then there?s no warranty.

I?ve been building musical electronics since PAiA, Electronic Projects for Musicians, and various magazines published interesting schematics. I?ve also designed several commercial musical products. The price is only vaguely bounded by the component costs. There are just so many other costs that aren?t inside the box that you receive. I don?t want to discourage you from trying to build something yourself, but you?d be surprised how much difference there is between the cost of what?s listed on the schematic versus the total cost. For one thing, the exact same parts can vary by 10x or more just based on how many you buy, whether it?s 1 or 1,000,000. But maybe you can figure out how to make a $1,000 gtr looper that sells for $200.

These days, I pretty much only build things myself if nobody makes anything like it. Stuff that?s already been created as a commercial product, even if I only use some of the features, just isn?t worth the time worrying about a few hundred dollars.

Brian


On Sep 2, 2019, at 5:04 PM, sleepy_dog at gmx.de wrote:
> I recently looked at some of those loopers that are apparently
> especially popupar among guitarists, but also other instrumentalists.
> I was also more specifically looking for one with +48V XLR input to use
> it for both, instant feedback for practising singing without messing
> with computer software, and also actually practicing instruments /
> jamming, experimenting. The handling (or rather, "footling"?) of the
> looper for this "sing a line, step on it, hear it" seems even simpler /
> less distracting than just using my litte old portable recorder - nice
> for concentrating on self monitoring/correction in this regard.
> 
> So I found e.g. the Boss RC30, which has 2 foot switches, a display, a
> few more small buttons, evidently some RAM and some not too complicated
> DSP stuff.
> Costs about 200 $.
> 
> Or the RC300, 3x or so as wide, more foot switches.
> This costs ~ 500 $ and doesn't even have stuff like time stretching,
> which *cough* pedals for ~ 1000 $ I've seen have.
> 
> 
> Now, in my hobbyist imagination, who has done some projects roughly
> involving the things I imagine to be involved here, but not exatcly the
> type of product, it seems like this stuff should neither be exactly
> rocket science, the R&D shouldn't be too tough on those, nor special
> super duper hardware to make it happen (also hinted at the fact that
> some of the products are out there for ~ 10 years, unchanged).
> While I see that the rugged cases & switches do cost something - 500 or
> more? Get real. My age old laptop which cost less than that back than
> could do a lot more than what those things do, apart from being stomped
> on hard and still work.
> 
> What am I missing, what magic is in there to justify those kinda prices?
> Let's not forget that those aren't boutique synth modules, but rather
> mass produced pedals for one of the most popular musical instruments.
> 
> I almost was about to slap something together involving a Raspberry Pi
> Z, an audio codec, and some cheap thomann stackable foot swtiches.
> But that'll probably result in not-so-low latency with the Linux audio
> stack in the background :)
> 
> I will probably bite the bullet for the RC 30 for ~ 200, one of the few
> smaller ones with XLR mic in, albeit some reported usability issues and
> paying also for some absolutely pointless built-in effects... (FX are
> cool, just not those)
> 
> - Steve
> 



From info at extrinia.com  Thu Sep  5 10:59:46 2019
From: info at extrinia.com (John P Shea)
Date: Thu, 5 Sep 2019 18:59:46 +1000
Subject: [sdiy] OT: Guitar FX - Loopers & prices - what magic is in
 there?
In-Reply-To: <F592D565-60F1-4AA5-B621-620F158B062D@audiobanshee.com>
References: <9ec7df10-1bea-6a5b-52f2-8848b0c577af@gmx.de>
 <F592D565-60F1-4AA5-B621-620F158B062D@audiobanshee.com>
Message-ID: <CAFBTNJcoo42T==_KMS+tCiw+o8XQ3BWgdbyYGXiGG+DXnr1pQA@mail.gmail.com>

https://www.pjrc.com/diy-eurorack-looper/

For better quality converters, there is also the Audio Board, for which
there may be a new vers coming for the new Teensy 4 release (which has a
lot more RAM, but no DAC).

Regards,
JPS

On Thu, 5 Sep 2019 at 5:52 pm, <rsdio at audiobanshee.com> wrote:

> Steve,
>
> Nothing is priced based on component cost. Price comes from supply and
> demand.
>
> Of course, nobody will price gear *below* the cost of the components
> because that?s an unsustainable loss. The only exception is if they?re
> dumping old stock that?s already a loss - better to sell at a loss then
> than never sell at all, and better to stay in business long enough that the
> losses are offset by profits.
>
> On the flip side, though, there?s no upper limit on prices so long as
> they?re above the component costs. The only ?justification? needed is that
> people are willing to pay. The catch is that any company who tries to sell
> a product for too much will be surprised by the Behringers of the world who
> are willing to make a product as cheaply as possible and get closer to the
> cost of the components than their competitors. Nobody can predict the
> future with 100% certainty, and there?s always the risk that what gets
> manufactured will not ever sell, at least not the entire inventory.
>
> Basically, it all comes down to you. If you don?t think the full set of
> features is worth $1,000 then you can either build it yourself or buy a
> model with fewer features. Maybe you could even do without.
>
> You?re right that a maker Pi plus Linux would have latency, but you could
> learn real-time (RTOS or other) programming to avoid the latency. You might
> even have fun. I do. But unless you have experience with mechanical
> engineering, you might stomp on your baby a little too hard and then
> there?s no warranty.
>
> I?ve been building musical electronics since PAiA, Electronic Projects for
> Musicians, and various magazines published interesting schematics. I?ve
> also designed several commercial musical products. The price is only
> vaguely bounded by the component costs. There are just so many other costs
> that aren?t inside the box that you receive. I don?t want to discourage you
> from trying to build something yourself, but you?d be surprised how much
> difference there is between the cost of what?s listed on the schematic
> versus the total cost. For one thing, the exact same parts can vary by 10x
> or more just based on how many you buy, whether it?s 1 or 1,000,000. But
> maybe you can figure out how to make a $1,000 gtr looper that sells for
> $200.
>
> These days, I pretty much only build things myself if nobody makes
> anything like it. Stuff that?s already been created as a commercial
> product, even if I only use some of the features, just isn?t worth the time
> worrying about a few hundred dollars.
>
> Brian
>
>
> On Sep 2, 2019, at 5:04 PM, sleepy_dog at gmx.de wrote:
> > I recently looked at some of those loopers that are apparently
> > especially popupar among guitarists, but also other instrumentalists.
> > I was also more specifically looking for one with +48V XLR input to use
> > it for both, instant feedback for practising singing without messing
> > with computer software, and also actually practicing instruments /
> > jamming, experimenting. The handling (or rather, "footling"?) of the
> > looper for this "sing a line, step on it, hear it" seems even simpler /
> > less distracting than just using my litte old portable recorder - nice
> > for concentrating on self monitoring/correction in this regard.
> >
> > So I found e.g. the Boss RC30, which has 2 foot switches, a display, a
> > few more small buttons, evidently some RAM and some not too complicated
> > DSP stuff.
> > Costs about 200 $.
> >
> > Or the RC300, 3x or so as wide, more foot switches.
> > This costs ~ 500 $ and doesn't even have stuff like time stretching,
> > which *cough* pedals for ~ 1000 $ I've seen have.
> >
> >
> > Now, in my hobbyist imagination, who has done some projects roughly
> > involving the things I imagine to be involved here, but not exatcly the
> > type of product, it seems like this stuff should neither be exactly
> > rocket science, the R&D shouldn't be too tough on those, nor special
> > super duper hardware to make it happen (also hinted at the fact that
> > some of the products are out there for ~ 10 years, unchanged).
> > While I see that the rugged cases & switches do cost something - 500 or
> > more? Get real. My age old laptop which cost less than that back than
> > could do a lot more than what those things do, apart from being stomped
> > on hard and still work.
> >
> > What am I missing, what magic is in there to justify those kinda prices?
> > Let's not forget that those aren't boutique synth modules, but rather
> > mass produced pedals for one of the most popular musical instruments.
> >
> > I almost was about to slap something together involving a Raspberry Pi
> > Z, an audio codec, and some cheap thomann stackable foot swtiches.
> > But that'll probably result in not-so-low latency with the Linux audio
> > stack in the background :)
> >
> > I will probably bite the bullet for the RC 30 for ~ 200, one of the few
> > smaller ones with XLR mic in, albeit some reported usability issues and
> > paying also for some absolutely pointless built-in effects... (FX are
> > cool, just not those)
> >
> > - Steve
> >
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
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From srmaietta at yahoo.com  Sat Sep  7 17:04:01 2019
From: srmaietta at yahoo.com (Steve Maietta)
Date: Sat, 7 Sep 2019 11:04:01 -0400
Subject: [sdiy] SOLOMAN David DIY project FS..
Message-ID: <158B10E2-B6EE-40EC-9C90-C6A8E43605D0@yahoo.com>

I?ve got over $1400 invested so far and a child coming, my second, very soon. There?s no way I can get this going and I?m willing to part with this for a good price. If anyone wants in on the alpha side of things which also will give you access to the other crazy DIY projects they are putting together please send me an email. Thanks for reading,

~Steve



From tom at electricdruid.net  Sun Sep  8 17:39:33 2019
From: tom at electricdruid.net (Tom Wiltshire)
Date: Sun, 8 Sep 2019 16:39:33 +0100
Subject: [sdiy] LC delay lines and scanner chorus/vibrato taps
Message-ID: <07A8E3D4-A854-4F5B-8ECC-5254A7EBA330@electricdruid.net>

Hi all,

I?ve been playing with a modified version of J?rgen Haible?s scanner chorus/vibrato, described here:

	http://jhaible.com/legacy/interpolating_scanner_and_scanv/jh_interpolating_scanner_and_scanvib.html

Since JH has conveniently done the calculations for the delay line part and the 33mH inductors he used are still cheap and available, I?ve used that part without modification:

	http://jhaible.com/legacy/interpolating_scanner_and_scanv/scanner_vibrato_2008_page2_sch.pdf

What I?ve changed is the control and crossfade circuit. My version has a pair of DG406 16-to-1 switches for selecting taps from the delay line, and then an AS3360 dual VCA for crossfading between those taps. Control signals for these are generated in firmware on a PIC 16F1778. This chip usefully has  10-bit DAC channels that can be used to drive the VCAs, and by setting the DAC reference to the correct level, the output is perfectly scaled for the VCA. I?ve done a variable speed ?LFO? in firmware that can scan the delay line at three depths (as per the Hammond organ, more or less), but you can also feed in a 0-5CV and use that to scan the delay line.

However, while I?m comfortable with all that part, I know very little about transmission lines, beyond what I?ve read here:

	http://www.rhombus-ind.com/dlcat/app1_pas.pdf

My question is ?Are JH?s buffers on each tap necessary??. The paper noted above suggests that a load on each tap should be at least 10x the impedance of the delay line (calculated by JH as 840 ohms). That?d mean resistors to take signal from each tap should be roughly 10K or greater. That would work perfectly into an inverting mixer or virtual ground node (such as I have on the VCAs) and I could simply use weighted resistors values to get all the taps at the same level. However, I can?t get this part to work, and looking at the signals in the transmission line doesn?t tell me much since I don?t know what I?m looking at or looking for.

So, do I need the buffers? Would a 10K to virtual ground be too much load for each tap? At this rate, I?m going to finish up putting simple op-amp buffers on each tap as an experiment.

Thanks,
Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================




From jdec at mindspring.com  Sun Sep  8 19:32:38 2019
From: jdec at mindspring.com (BrightBoy)
Date: Sun, 8 Sep 2019 13:32:38 -0400 (GMT-04:00)
Subject: [sdiy] LC delay lines and scanner chorus/vibrato taps
Message-ID: <630949019.3322.1567963958075@wamui-merida.atl.sa.earthlink.net>

Here's an old patent that you can peruse for some ideas:

http://pat2pdf.org/patents/pat4114499.pdf

Jeff

-----Original Message-----
>From: Tom Wiltshire <tom at electricdruid.net>
>Sent: Sep 8, 2019 11:39 AM
>To: *SYNTH DIY <Synth-diy at synth-diy.org>
>Subject: [sdiy] LC delay lines and scanner chorus/vibrato taps
>
>Hi all,
>
>I?ve been playing with a modified version of J?rgen Haible?s scanner chorus/vibrato, described here:
>
>	http://jhaible.com/legacy/interpolating_scanner_and_scanv/jh_interpolating_scanner_and_scanvib.html
>
>Since JH has conveniently done the calculations for the delay line part and the 33mH inductors he used are still cheap and available, I?ve used that part without modification:
>
>	http://jhaible.com/legacy/interpolating_scanner_and_scanv/scanner_vibrato_2008_page2_sch.pdf
>
>What I?ve changed is the control and crossfade circuit. My version has a pair of DG406 16-to-1 switches for selecting taps from the delay line, and then an AS3360 dual VCA for crossfading between those taps. Control signals for these are generated in firmware on a PIC 16F1778. This chip usefully has  10-bit DAC channels that can be used to drive the VCAs, and by setting the DAC reference to the correct level, the output is perfectly scaled for the VCA. I?ve done a variable speed ?LFO? in firmware that can scan the delay line at three depths (as per the Hammond organ, more or less), but you can also feed in a 0-5CV and use that to scan the delay line.
>
>However, while I?m comfortable with all that part, I know very little about transmission lines, beyond what I?ve read here:
>
>	http://www.rhombus-ind.com/dlcat/app1_pas.pdf
>
>My question is ?Are JH?s buffers on each tap necessary??. The paper noted above suggests that a load on each tap should be at least 10x the impedance of the delay line (calculated by JH as 840 ohms). That?d mean resistors to take signal from each tap should be roughly 10K or greater. That would work perfectly into an inverting mixer or virtual ground node (such as I have on the VCAs) and I could simply use weighted resistors values to get all the taps at the same level. However, I can?t get this part to work, and looking at the signals in the transmission line doesn?t tell me much since I don?t know what I?m looking at or looking for.
>
>So, do I need the buffers? Would a 10K to virtual ground be too much load for each tap? At this rate, I?m going to finish up putting simple op-amp buffers on each tap as an experiment.
>
>Thanks,
>Tom
>
>==================
>       Electric Druid
>Synth & Stompbox DIY
>==================
>
>
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at synth-diy.org
>http://synth-diy.org/mailman/listinfo/synth-diy



From rburnett at richieburnett.co.uk  Sun Sep  8 20:31:38 2019
From: rburnett at richieburnett.co.uk (Richie Burnett)
Date: Sun, 8 Sep 2019 19:31:38 +0100
Subject: [sdiy] LC delay lines and scanner chorus/vibrato taps
In-Reply-To: <07A8E3D4-A854-4F5B-8ECC-5254A7EBA330@electricdruid.net>
References: <07A8E3D4-A854-4F5B-8ECC-5254A7EBA330@electricdruid.net>
Message-ID: <459F15341F984C5F9F8E92F7FF729D21@RICHIEPC>

Hi Tom,

That cascade of LC pi-filters is what engineers call a lumped-element model 
of a transmission line.  You can delay a signal just by sending it down a 
length of coaxial cable, but it travels at the speed of light in the cable. 
So you need a looooong length of cable to get any significant delay at audio 
frequencies.  This is where the lumped-element approximation comes in handy. 
All those cascaded L's and C's model the behaviour of a much longer length 
of cable with taps every "30km" or so!  The catch is that modelling the 
cable like this in large "lengths" limits the effective bandwidth to only a 
few kHz.  Not a bad compromise given the intended application though.

In order to work properly the lumped element delay line (or a length of coax 
for that matter) needs to be driven from a source with the correct source 
impedance and terminated into a load with the correct load impedance.  If 
you don't do this you get reflections from the impedance discontinuities, 
and your signal bounces back from the ends of the delay line resulting in 
standing waves.  Think of the way that light reflects from the surface of a 
window or from the surface of water when it has to transition from one 
medium to another one.  (As an aside, this is why most signal generators and 
scopes designed for RF work have the option to use 50R source and input 
impedances so that everything can be matched throughout and you don't get 
any reflections.)

Now, if you apply any loading at all along the transmission line (or at the 
taps of the delay line) it will disturb the characteristic impedance of the 
line at that point and will cause reflections.  It doesn't have to be a 
resistive load, even adding some capacitive loading at a point along the 
line will cause reflections, and this modifies the frequency response.  So I 
would say that the high input-impedance buffers are essential to prevent 
loading the transmission line and modifying its operation.  Especially given 
that there are many of them spaced along the delay line.  Also every time 
you load the line resistively you are removing energy from it.  This loss 
adds to the "insertion loss" of the delay line caused by all of the 
inductors and capacitors, and results in a weaker signal coming out the end 
of the delay line.

This lumped element delay line is very amenable to simulation in something 
like LTspice if you have it.  So you could use that as a reference to debug 
your real circuit, and also to assess the amount by which loading at 
different tap points messes up the delay line operation.  If you simulate it 
in LTspice try to include the DC resistance of the inductors too, then you 
will get a better idea of the "insertion loss" through the whole delay line.

It's an interesting project, and I look forward to reading more about it as 
it progresses!

-Richie,

PS. As a practical note, make sure that the inductors you're using aren't 
magnetically coupling to each other.  If you're using toroidal inductors 
they keep most of the magnetic field inside.  But I don't know what type of 
indutors you are using.  If using ferrite stick inductors or gapped 
laminated iron-core inductors these tend to p!$$ out magnetic fields and 
couple effectively to nearby inductors that also have gaps in the magnetic 
core.  If all your inductors are gapped and right next to each other, your 
signal could potentially just couple magnetically from one inductor to the 
next to get to the output and "short cut" the delay line altogether!



-----Original Message----- 
From: Tom Wiltshire
Sent: Sunday, September 08, 2019 4:39 PM
To: *SYNTH DIY
Subject: [sdiy] LC delay lines and scanner chorus/vibrato taps

Hi all,

I?ve been playing with a modified version of J?rgen Haible?s scanner 
chorus/vibrato, described here:

http://jhaible.com/legacy/interpolating_scanner_and_scanv/jh_interpolating_scanner_and_scanvib.html

Since JH has conveniently done the calculations for the delay line part and 
the 33mH inductors he used are still cheap and available, I?ve used that 
part without modification:

http://jhaible.com/legacy/interpolating_scanner_and_scanv/scanner_vibrato_2008_page2_sch.pdf

What I?ve changed is the control and crossfade circuit. My version has a 
pair of DG406 16-to-1 switches for selecting taps from the delay line, and 
then an AS3360 dual VCA for crossfading between those taps. Control signals 
for these are generated in firmware on a PIC 16F1778. This chip usefully has 
10-bit DAC channels that can be used to drive the VCAs, and by setting the 
DAC reference to the correct level, the output is perfectly scaled for the 
VCA. I?ve done a variable speed ?LFO? in firmware that can scan the delay 
line at three depths (as per the Hammond organ, more or less), but you can 
also feed in a 0-5CV and use that to scan the delay line.

However, while I?m comfortable with all that part, I know very little about 
transmission lines, beyond what I?ve read here:

http://www.rhombus-ind.com/dlcat/app1_pas.pdf

My question is ?Are JH?s buffers on each tap necessary??. The paper noted 
above suggests that a load on each tap should be at least 10x the impedance 
of the delay line (calculated by JH as 840 ohms). That?d mean resistors to 
take signal from each tap should be roughly 10K or greater. That would work 
perfectly into an inverting mixer or virtual ground node (such as I have on 
the VCAs) and I could simply use weighted resistors values to get all the 
taps at the same level. However, I can?t get this part to work, and looking 
at the signals in the transmission line doesn?t tell me much since I don?t 
know what I?m looking at or looking for.

So, do I need the buffers? Would a 10K to virtual ground be too much load 
for each tap? At this rate, I?m going to finish up putting simple op-amp 
buffers on each tap as an experiment.

Thanks,
Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================


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Synth-diy mailing list
Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy


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From sleepy_dog at gmx.de  Mon Sep  9 00:24:45 2019
From: sleepy_dog at gmx.de (sleepy_dog at gmx.de)
Date: Mon, 9 Sep 2019 00:24:45 +0200
Subject: [sdiy] OT: Guitar FX - Loopers & prices - what magic is in
 there?
In-Reply-To: <F592D565-60F1-4AA5-B621-620F158B062D@audiobanshee.com>
References: <9ec7df10-1bea-6a5b-52f2-8848b0c577af@gmx.de>
 <F592D565-60F1-4AA5-B621-620F158B062D@audiobanshee.com>
Message-ID: <ccf209d5-49ac-bb8b-27e6-76f8c27a1bd8@gmx.de>


 > Nothing is priced based on component cost. Price comes from supply
and demand

true, although there seems to be a tendency in the realm of guitar
pedals that it does not seem to be insanely off for not too niche
things, with some exceptions. Well, maybe this is one of those. Or I
underestimate it. But some multi FX have a lot more going on inside,
compared to a looper.

Yeah, the mechanics part tends to be a tough one DIY wise, with those
mostly-metal things. That's why I toyed with the idea of repurposing
cheap momentary switch pedals ad connect them to a box that's not for
stomping on it.

I guess before I'd go to the trouble to use an RTOS on something like
the PI I'd be more inclined to use the somewhat familiar stm32f4, the
devboard that has a decent amount of RAM on it, and IIRC even an audio
codec, but I don't think I'll really have time for that, even though it
would be fun to implment something like that exactly the way I want it,
and not with the quirky / economical UIs those things tend to have.

Anyway, thanks for your reply.

rsdio at audiobanshee.com wrote:
> Steve,
>
> Nothing is priced based on component cost. Price comes from supply and demand.
>
> Of course, nobody will price gear *below* the cost of the components because that?s an unsustainable loss. The only exception is if they?re dumping old stock that?s already a loss - better to sell at a loss then than never sell at all, and better to stay in business long enough that the losses are offset by profits.
>
> On the flip side, though, there?s no upper limit on prices so long as they?re above the component costs. The only ?justification? needed is that people are willing to pay. The catch is that any company who tries to sell a product for too much will be surprised by the Behringers of the world who are willing to make a product as cheaply as possible and get closer to the cost of the components than their competitors. Nobody can predict the future with 100% certainty, and there?s always the risk that what gets manufactured will not ever sell, at least not the entire inventory.
>
> Basically, it all comes down to you. If you don?t think the full set of features is worth $1,000 then you can either build it yourself or buy a model with fewer features. Maybe you could even do without.
>
> You?re right that a maker Pi plus Linux would have latency, but you could learn real-time (RTOS or other) programming to avoid the latency. You might even have fun. I do. But unless you have experience with mechanical engineering, you might stomp on your baby a little too hard and then there?s no warranty.
>
> I?ve been building musical electronics since PAiA, Electronic Projects for Musicians, and various magazines published interesting schematics. I?ve also designed several commercial musical products. The price is only vaguely bounded by the component costs. There are just so many other costs that aren?t inside the box that you receive. I don?t want to discourage you from trying to build something yourself, but you?d be surprised how much difference there is between the cost of what?s listed on the schematic versus the total cost. For one thing, the exact same parts can vary by 10x or more just based on how many you buy, whether it?s 1 or 1,000,000. But maybe you can figure out how to make a $1,000 gtr looper that sells for $200.
>
> These days, I pretty much only build things myself if nobody makes anything like it. Stuff that?s already been created as a commercial product, even if I only use some of the features, just isn?t worth the time worrying about a few hundred dollars.
>
> Brian
>
>
> On Sep 2, 2019, at 5:04 PM, sleepy_dog at gmx.de wrote:
>> I recently looked at some of those loopers that are apparently
>> especially popupar among guitarists, but also other instrumentalists.
>> I was also more specifically looking for one with +48V XLR input to use
>> it for both, instant feedback for practising singing without messing
>> with computer software, and also actually practicing instruments /
>> jamming, experimenting. The handling (or rather, "footling"?) of the
>> looper for this "sing a line, step on it, hear it" seems even simpler /
>> less distracting than just using my litte old portable recorder - nice
>> for concentrating on self monitoring/correction in this regard.
>>
>> So I found e.g. the Boss RC30, which has 2 foot switches, a display, a
>> few more small buttons, evidently some RAM and some not too complicated
>> DSP stuff.
>> Costs about 200 $.
>>
>> Or the RC300, 3x or so as wide, more foot switches.
>> This costs ~ 500 $ and doesn't even have stuff like time stretching,
>> which *cough* pedals for ~ 1000 $ I've seen have.
>>
>>
>> Now, in my hobbyist imagination, who has done some projects roughly
>> involving the things I imagine to be involved here, but not exatcly the
>> type of product, it seems like this stuff should neither be exactly
>> rocket science, the R&D shouldn't be too tough on those, nor special
>> super duper hardware to make it happen (also hinted at the fact that
>> some of the products are out there for ~ 10 years, unchanged).
>> While I see that the rugged cases & switches do cost something - 500 or
>> more? Get real. My age old laptop which cost less than that back than
>> could do a lot more than what those things do, apart from being stomped
>> on hard and still work.
>>
>> What am I missing, what magic is in there to justify those kinda prices?
>> Let's not forget that those aren't boutique synth modules, but rather
>> mass produced pedals for one of the most popular musical instruments.
>>
>> I almost was about to slap something together involving a Raspberry Pi
>> Z, an audio codec, and some cheap thomann stackable foot swtiches.
>> But that'll probably result in not-so-low latency with the Linux audio
>> stack in the background :)
>>
>> I will probably bite the bullet for the RC 30 for ~ 200, one of the few
>> smaller ones with XLR mic in, albeit some reported usability issues and
>> paying also for some absolutely pointless built-in effects... (FX are
>> cool, just not those)
>>
>> - Steve
>>




From rsdio at audiobanshee.com  Mon Sep  9 01:20:22 2019
From: rsdio at audiobanshee.com (rsdio at audiobanshee.com)
Date: Sun, 8 Sep 2019 16:20:22 -0700
Subject: [sdiy] OT: Guitar FX - Loopers & prices - what magic is in
 there?
In-Reply-To: <ccf209d5-49ac-bb8b-27e6-76f8c27a1bd8@gmx.de>
References: <9ec7df10-1bea-6a5b-52f2-8848b0c577af@gmx.de>
 <F592D565-60F1-4AA5-B621-620F158B062D@audiobanshee.com>
 <ccf209d5-49ac-bb8b-27e6-76f8c27a1bd8@gmx.de>
Message-ID: <541138FF-9379-4748-9268-636A7C9E9B04@audiobanshee.com>


On Sep 8, 2019, at 3:24 PM, sleepy_dog at gmx.de wrote:
> > Nothing is priced based on component cost. Price comes from supply
> and demand
> 
> true, although there seems to be a tendency in the realm of guitar
> pedals that it does not seem to be insanely off for not too niche
> things, with some exceptions. Well, maybe this is one of those. Or I
> underestimate it. But some multi FX have a lot more going on inside,
> compared to a looper.

I know what you mean about boutique guitar pedals. Like the audiophile industry, there is plenty of snake oil in that area. If only people weren?t willing to pay extra for crap.

I?m going to make a guess here and say that anything digital like a looper is not going to intersect with the crazy hype overpriced boutique guitar pedal market. I could be wrong, but I would assume those guys shun digital when looking for magic pedals.


> Yeah, the mechanics part tends to be a tough one DIY wise, with those
> mostly-metal things. That's why I toyed with the idea of repurposing
> cheap momentary switch pedals ad connect them to a box that's not for
> stomping on it.

That?s a good approach. I recently designed a phono preamp starting with the case from a $14 product. I only used the screw terminal for the ground lug from the turntable. The rest of the components were my design, arranged to fit the existing holes in the case.

There?s a wonderful diary in an online forum from a headphone amplifier designer who explained how the whole company?s success hinged on finding a way to make a custom case for less than $100.


> I guess before I'd go to the trouble to use an RTOS on something like
> the PI I'd be more inclined to use the somewhat familiar stm32f4, the
> devboard that has a decent amount of RAM on it, and IIRC even an audio
> codec, but I don't think I'll really have time for that, even though it
> would be fun to implment something like that exactly the way I want it,
> and not with the quirky / economical UIs those things tend to have.

Personally, I?d recommend going for broke. Rather than settle for a general-purpose processor like the ARM (STM32F4), take the dive and learn to program a DSP. Something like the Texas Instruments TMS320 or the Analog Devices SHARC, the latter of which is very popular in music industry products. There used to be the Motorola 68000 DSP, and I think that Freescale continued it, but it may not be available any more. I do have several audio products with 68k processors, including some chips that come with audio software in ROM.


> Anyway, thanks for your reply.

You?re welcome.

Brian




From list at mikebeauchamp.com  Tue Sep 10 04:24:02 2019
From: list at mikebeauchamp.com (Mike Beauchamp)
Date: Mon, 9 Sep 2019 22:24:02 -0400
Subject: [sdiy] OT: Guitar FX - Loopers & prices - what magic is in
 there?
In-Reply-To: <9ec7df10-1bea-6a5b-52f2-8848b0c577af@gmx.de>
References: <9ec7df10-1bea-6a5b-52f2-8848b0c577af@gmx.de>
Message-ID: <72ab0862-5652-cff4-3987-83db630ccf99@mikebeauchamp.com>

Hi Steve,

I just want to say that you can't always compare the cost of DIY with 
the cost of a product. There's some things that can get overlooked when 
we say "That's so cheap, I can make it for cheaper".

- Retail Cost - your $500 looper sold to the store for $350, possibly 
through a distributor that bought it for $250 from the manufacturer and 
it needed to be shipped from overseas, possibly with import tax needing 
to be paid. Unsold units have to sit in a warehouse that costs money, 
etc, etc..

- Design and prototyping. When we DIY things we grab the knobs we have, 
drill some holes.. maybe sketch the layout out. I'm reading a Jony Ive 
bio right now and professional companies go nuts with designing.. every 
little detail is thought out (sometimes really badly, but that's a whole 
different post) and a lot of time ($$) goes into that.

- Certification - Companies gotta pay big bucks to have their stuff 
tested to ensure it doesn't catch fire, or kill people, or fuck with 
medical equipment and radios, etc.

Worker wages, benefits, custom molds, managers, bureaucracy, marketing, 
retail packaging, documentation, support, etc...


Maybe I'm just getting old.. but if I want a looper, I'll buy the 
second-hand looper that fits my needs and spend my time enjoying it. I 
don't want to worry about my amateur code bugging out during a gig 
because I tried to save a bit of dough. I take apart almost everything I 
own and am continuously amazed at the complexity we can stuff into things.


Mike


On 9/2/19 8:04 PM, sleepy_dog at gmx.de wrote:
> Hello list,
> 
> I recently looked at some of those loopers that are apparently
> especially popupar among guitarists, but also other instrumentalists.
> I was also more specifically looking for one with +48V XLR input to use
> it for both, instant feedback for practising singing without messing
> with computer software, and also actually practicing instruments /
> jamming, experimenting. The handling (or rather, "footling"?) of the
> looper for this "sing a line, step on it, hear it" seems even simpler /
> less distracting than just using my litte old portable recorder - nice
> for concentrating on self monitoring/correction in this regard.
> 
> So I found e.g. the Boss RC30, which has 2 foot switches, a display, a
> few more small buttons, evidently some RAM and some not too complicated
> DSP stuff.
> Costs about 200 $.
> 
> Or the RC300, 3x or so as wide, more foot switches.
> This costs ~ 500 $ and doesn't even have stuff like time stretching,
> which *cough* pedals for ~ 1000 $ I've seen have.
> 
> 
> Now, in my hobbyist imagination, who has done some projects roughly
> involving the things I imagine to be involved here, but not exatcly the
> type of product, it seems like this stuff should neither be exactly
> rocket science, the R&D shouldn't be too tough on those, nor special
> super duper hardware to make it happen (also hinted at the fact that
> some of the products are out there for ~ 10 years, unchanged).
> While I see that the rugged cases & switches do cost something - 500 or
> more? Get real. My age old laptop which cost less than that back than
> could do a lot more than what those things do, apart from being stomped
> on hard and still work.
> 
> What am I missing, what magic is in there to justify those kinda prices?
> Let's not forget that those aren't boutique synth modules, but rather
> mass produced pedals for one of the most popular musical instruments.
> 
> I almost was about to slap something together involving a Raspberry Pi
> Z, an audio codec, and some cheap thomann stackable foot swtiches.
> But that'll probably result in not-so-low latency with the Linux audio
> stack in the background :)
> 
> I will probably bite the bullet for the RC 30 for ~ 200, one of the few
> smaller ones with XLR mic in, albeit some reported usability issues and
> paying also for some absolutely pointless built-in effects... (FX are
> cool, just not those)
> 
> - Steve
> 
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy


From bah13 at cornell.edu  Wed Sep 11 04:58:33 2019
From: bah13 at cornell.edu (Bernard Arthur Hutchins, Jr)
Date: Wed, 11 Sep 2019 02:58:33 +0000
Subject: [sdiy] Q-Enhancement with Cascaded Bandpass is Modest
Message-ID: <DM6PR04MB60436386937188879298D2B2BCB10@DM6PR04MB6043.namprd04.prod.outlook.com>

A week ago (Vocoder thread), I said, based on my memory of examining the notion many years ago, that the idea of cascading two identical BP filters to sharpen Q was distressingly slow.

If I wrote this up in the distant past, I can't find it.   Anyone?

I did it again:

http://electronotes.netfirms.com/ENWN58.pdf

and found cascading multiplies the original Q by 1.5537, for all Q.   Did I make a mistake?

Nice-looking bandpass - just not much sharper Q-wise.

Bernie



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From fanwander at mnet-online.de  Wed Sep 11 16:42:12 2019
From: fanwander at mnet-online.de (Florian Anwander)
Date: Wed, 11 Sep 2019 16:42:12 +0200
Subject: [sdiy] Roland's cross mod and metal sync
In-Reply-To: <BD27B9C9-3270-41B0-BB1A-F6DA9651611D@electricdruid.net>
References: <BD27B9C9-3270-41B0-BB1A-F6DA9651611D@electricdruid.net>
Message-ID: <5D7907C4.8090505@mnet-online.de>

Hello Tom


On 27.08.19 16:58 , Tom Wiltshire wrote:
> Any corrections, comments, or feedback are always appreciated. I?ve only just got this into a reasonable condition, so I don?t suppose it?s perfect just yet!
That is a very fine article. Thanks for it!

Just an addon: It would have been easy for Roland to provide linear FM 
for the JP-6 as it works with a CEM3340, which provides a dedicated 
linFM input. And it is a shame that they didn't.

(I think you know already my modification that changes the FM from exp 
to lin -> http://www.florian-anwander.de/roland_jp6/)

Florian


From 21pointy at tpg.com.au  Thu Sep 12 00:59:58 2019
From: 21pointy at tpg.com.au (Adam Inglis)
Date: Thu, 12 Sep 2019 08:59:58 +1000
Subject: [sdiy] Roland's cross mod and metal sync
In-Reply-To: <5D7907C4.8090505@mnet-online.de>
References: <BD27B9C9-3270-41B0-BB1A-F6DA9651611D@electricdruid.net>
 <5D7907C4.8090505@mnet-online.de>
Message-ID: <0777F518-E27C-44C9-A730-33B0C488EF6B@tpg.com.au>


> On 12 Sep 2019, at 12:42 AM, Florian Anwander <fanwander at mnet-online.de> wrote:
> 
> (I think you know already my modification that changes the FM from exp to lin -> http://www.florian-anwander.de/roland_jp6/ <http://www.florian-anwander.de/roland_jp6/>)

Wow, Florian, the sound of those mods is fabulous. I?ve not heard a JP6 live, but my JP8 certainly can?t get vocal textures like you?re getting there.

Adam
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From thx1138 at earthlink.net  Wed Sep 18 04:23:26 2019
From: thx1138 at earthlink.net (TERRY SHULTZ)
Date: Tue, 17 Sep 2019 19:23:26 -0700
Subject: [sdiy] Synclavier II 5 1/4" Boot Diskettes needed
Message-ID: <1649FB7B-3785-4426-9807-172727D5E2A1@earthlink.net>

Hi Synth DIY friends,

I need to get some Synclavier II 5 1/4? Boot diskettes.

Anyone have these or know where to find them,  please email me back.

Thanks,

Terry Shultz

THX1138 at earthlink.net


From eric at ericframpton.com  Thu Sep 19 01:18:34 2019
From: eric at ericframpton.com (Eric Frampton)
Date: Wed, 18 Sep 2019 19:18:34 -0400
Subject: [sdiy] Prophet-5 help?
Message-ID: <F596B174-ADDA-40E5-858C-9A05A659622A@ericframpton.com>

I?m (still) working on this rev 3.0 Prophet-5 (ugh) and have managed to back myself into a corner.

I put the Retrolinear replacement PSU in there with their Memory Watchdog controller chiclet; those parts are working fine.
I?ve done the 2716 EPROM mod and installed some v.8.2 ROMs.

The unit seems to be working correctly except for one major issue: Since doing the 2716 mod and installing the new firmware, now whenever I got to record a patch, the unit doesn?t exit Record mode (also, the LED never extinguishes) and the patch isn?t written. Unfortunately, because the other mods are done, I can?t backtrack to the 2708?s.

If I hit Record+Load, the unit *does* seem to drop into Cassette Load mode, so I think the front panel logic is OK.

I can see expected changes at both U320 and U323 when I move the back panel Rec Enable switch
I can see active data and address lines on all RAM and EPROMs
I?ve tried pulling individual RAM IC?s
I?ve tried pulling NVRAM IC?s and swapping them with spares

I?m not seeing any change on pin 5 (A15) of the CPU, which is one input of the gate whose output is U320:11.

Thoughts?

e




From brianw at audiobanshee.com  Thu Sep 19 08:26:12 2019
From: brianw at audiobanshee.com (Brian Willoughby)
Date: Wed, 18 Sep 2019 23:26:12 -0700
Subject: [sdiy] Prophet-5 help?
In-Reply-To: <F596B174-ADDA-40E5-858C-9A05A659622A@ericframpton.com>
References: <F596B174-ADDA-40E5-858C-9A05A659622A@ericframpton.com>
Message-ID: <3467AF43-F78C-4737-AC10-64B7EDDE28D3@audiobanshee.com>

A) Did the original 2716 EPROMs have v.8.2 firmware? ? or a different version?

Do you have an EPROM reader/burner so that you can read the data off the old 2716 chips?

You can?t go back to 2716 chips, but you can literally copy the data from two 2716 chips and put them on a single 2732, and then you will be running original firmware.

My point here is that if you weren?t running v.8.2 before, then that might not be the right version for your exact hardware revision. There were four different Rev 3 releases. I?m not familiar with whether they each required different firmware, but it?s not like the machine can tell you that it has incompatible firmware installed - other than when it doesn?t work right.


B) Are you sure that your v.8.2 firmware images are correct? By ?correct? I mean that all the data is there and it hasn?t been corrupted somehow.

I can?t remember which synth it was - maybe the Oberheim Matrix-12 - but I got one set of EPROM data that was flat-out wrong. The data was shifted in memory, with an empty header. It was sort of obvious, because the data was too large to fit exactly in the EPROM it was intended for. Luckily, I had three different sources for firmware, so I was able to confirm that one copy had the right data in the wrong place. This particular set of firmware files would never run if installed.

This is one reason I suggest reading a pair of your original 2716 chips and writing the collected data to a 2732. Repeat the process for the correct number of chips. That way, you will know that you?re running the right firmware even though the EPROM socket is literally wired for a different size. It helps to have a disassembler for the processor in the Prophet and some knowledge of how to confirm that the data is even potentially correct, but I realize that?s a tall order.


C) After juggling things with supply and memory, you might need to initialize things before they will work. I remember learning about a set of Prophet firmware chips that are designed to initialize, calibrate, and write default presets into the P-5 battery-backed RAM. This is especially necessary for the older ones like my Rev 2 that don?t even have a cassette interface. You may not have the same issue since you have cassette, but perhaps there is still something that needs to be initialized in the battery-backed preset RAM before saving patches will work.


D) When you drop into Cassette Load mode, does it actually restore fully functional presets?


E) I haven?t pulled out the schematics to look into the details of your U320 and U323 references. It?s late at night here in Seattle...

Brian


On Sep 18, 2019, at 4:18 PM, Eric Frampton <eric at ericframpton.com> wrote:
> I?m (still) working on this rev 3.0 Prophet-5 (ugh) and have managed to back myself into a corner.
> 
> I put the Retrolinear replacement PSU in there with their Memory Watchdog controller chiclet; those parts are working fine.
> I?ve done the 2716 EPROM mod and installed some v.8.2 ROMs.
> 
> The unit seems to be working correctly except for one major issue: Since doing the 2716 mod and installing the new firmware, now whenever I got to record a patch, the unit doesn?t exit Record mode (also, the LED never extinguishes) and the patch isn?t written. Unfortunately, because the other mods are done, I can?t backtrack to the 2708?s.
> 
> If I hit Record+Load, the unit *does* seem to drop into Cassette Load mode, so I think the front panel logic is OK.
> 
> I can see expected changes at both U320 and U323 when I move the back panel Rec Enable switch
> I can see active data and address lines on all RAM and EPROMs
> I?ve tried pulling individual RAM IC?s
> I?ve tried pulling NVRAM IC?s and swapping them with spares
> 
> I?m not seeing any change on pin 5 (A15) of the CPU, which is one input of the gate whose output is U320:11.
> 
> Thoughts?
> 
> e



From eric at ericframpton.com  Fri Sep 20 06:21:27 2019
From: eric at ericframpton.com (Eric Frampton)
Date: Fri, 20 Sep 2019 00:21:27 -0400
Subject: [sdiy] Prophet-5 help?
In-Reply-To: <3467AF43-F78C-4737-AC10-64B7EDDE28D3@audiobanshee.com>
References: <F596B174-ADDA-40E5-858C-9A05A659622A@ericframpton.com>
 <3467AF43-F78C-4737-AC10-64B7EDDE28D3@audiobanshee.com>
Message-ID: <238CAEC7-7B61-4392-B6DD-99E15BA6CFC1@ericframpton.com>

replies inline

> On Sep 19, 2019, at 2:26 AM, Brian Willoughby <brianw at audiobanshee.com> wrote:
> 
> A) Did the original 2716 EPROMs have v.8.2 firmware? ? or a different version?

They were originally 2708?s and had v.8.1 (IIRC - I?m not in front of my notes right now)

> Do you have an EPROM reader/burner so that you can read the data off the old 2716 chips?

Mine won?t read 2708?s, no.

> My point here is that if you weren?t running v.8.2 before, then that might not be the right version for your exact hardware revision. There were four different Rev 3 releases. I?m not familiar with whether they each required different firmware, but it?s not like the machine can tell you that it has incompatible firmware installed - other than when it doesn?t work right.

According to the service docs, some S/N?s shipped with 8.0, and some 8.1, but according to later service docs 8.2 shipped after the fact to resolve an issue where units would spontaneously drop into Edit, so I?m assuming this would work in any earlier units. I may be assuming wrong.

> B) Are you sure that your v.8.2 firmware images are correct? By ?correct? I mean that all the data is there and it hasn?t been corrupted somehow.

I have no way to check it, besides verifying checksums with the original files (which do pass compared with the chips).

> I can?t remember which synth it was - maybe the Oberheim Matrix-12 - but I got one set of EPROM data that was flat-out wrong.

Yup - it was the Xpander. There was a dump of the ROMs floating around which was incorrect.

> This is one reason I suggest reading a pair of your original 2716 chips and writing the collected data to a 2732. Repeat the process for the correct number of chips. That way, you will know that you?re running the right firmware even though the EPROM socket is literally wired for a different size. It helps to have a disassembler for the processor in the Prophet and some knowledge of how to confirm that the data is even potentially correct, but I realize that?s a tall order.

That?s way beyond my current experience, unfortunately.

> C) After juggling things with supply and memory, you might need to initialize things before they will work. I remember learning about a set of Prophet firmware chips that are designed to initialize, calibrate, and write default presets into the P-5 battery-backed RAM. This is especially necessary for the older ones like my Rev 2 that don?t even have a cassette interface. You may not have the same issue since you have cassette, but perhaps there is still something that needs to be initialized in the battery-backed preset RAM before saving patches will work.

I?d love to have a copy of the PROG5 EPROM and the 3.0 memory test, but don?t have copies of either one.

> D) When you drop into Cassette Load mode, does it actually restore fully functional presets??

It does not, but cassette loads being the dodgy things they are, there may be other factors at play.

> E) I haven?t pulled out the schematics to look into the details of your U320 and U323 references. It?s late at night here in Seattle?

Word.

e

> Brian
> 
> 
> On Sep 18, 2019, at 4:18 PM, Eric Frampton <eric at ericframpton.com> wrote:
>> I?m (still) working on this rev 3.0 Prophet-5 (ugh) and have managed to back myself into a corner.
>> 
>> I put the Retrolinear replacement PSU in there with their Memory Watchdog controller chiclet; those parts are working fine.
>> I?ve done the 2716 EPROM mod and installed some v.8.2 ROMs.
>> 
>> The unit seems to be working correctly except for one major issue: Since doing the 2716 mod and installing the new firmware, now whenever I got to record a patch, the unit doesn?t exit Record mode (also, the LED never extinguishes) and the patch isn?t written. Unfortunately, because the other mods are done, I can?t backtrack to the 2708?s.
>> 
>> If I hit Record+Load, the unit *does* seem to drop into Cassette Load mode, so I think the front panel logic is OK.
>> 
>> I can see expected changes at both U320 and U323 when I move the back panel Rec Enable switch
>> I can see active data and address lines on all RAM and EPROMs
>> I?ve tried pulling individual RAM IC?s
>> I?ve tried pulling NVRAM IC?s and swapping them with spares
>> 
>> I?m not seeing any change on pin 5 (A15) of the CPU, which is one input of the gate whose output is U320:11.
>> 
>> Thoughts?
>> 
>> e
> 




From grant at musictechnologiesgroup.com  Fri Sep 20 19:22:08 2019
From: grant at musictechnologiesgroup.com (MTG)
Date: Fri, 20 Sep 2019 10:22:08 -0700
Subject: [sdiy] Prophet-5 help?
In-Reply-To: <238CAEC7-7B61-4392-B6DD-99E15BA6CFC1@ericframpton.com>
References: <F596B174-ADDA-40E5-858C-9A05A659622A@ericframpton.com>
 <3467AF43-F78C-4737-AC10-64B7EDDE28D3@audiobanshee.com>
 <238CAEC7-7B61-4392-B6DD-99E15BA6CFC1@ericframpton.com>
Message-ID: <a1efbf06-fd5f-4cb7-d3f0-321494a40efe@musictechnologiesgroup.com>

I would go a step beyond a checksum since they are so easily fooled. 
There are lots of utilities that will tell you a CRC or MD5 or some 
other more substantial method. I use the Kontron CRC since it was
designed for EPROM data
(https://www.dropbox.com/s/akd20krcr3h7g26/KontronCRC.zip?dl=0)

GB

On 9/19/2019 9:21 PM, Eric Frampton wrote:
>> B) Are you sure that your v.8.2 firmware images are correct? By ?correct? I mean that all the data is there and it hasn?t been corrupted somehow.
> 
> I have no way to check it, besides verifying checksums with the original files (which do pass compared with the chips).


From matrixsynth at gmail.com  Sun Sep 22 06:38:58 2019
From: matrixsynth at gmail.com (matrix)
Date: Sat, 21 Sep 2019 21:38:58 -0700
Subject: [sdiy] How Do You Join The List?
Message-ID: <CAPR-mM_b2aTDEBgtFAKNsfcGViBMa+qb=s0quDhTkRFNcn0M8w@mail.gmail.com>

Anyone know how to join the list nowadays?  The link at the bottom of
http://search.retrosynth.com/synth-diy/index.html errors out.  Is there a
new link?  I sometimes get people asking for SDIY advice.  For example, in
the comments of this recent post:
https://www.matrixsynth.com/2015/07/tiergrinder-tr-808-clone.html

These requests rarely come in, so I hope it's OK to refer them here.  If
not, let me know.

-- 

cheers,
matrix
http://www.matrixsynth.com
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From ben.pi.bradley at gmail.com  Sun Sep 22 06:58:09 2019
From: ben.pi.bradley at gmail.com (Ben Bradley)
Date: Sun, 22 Sep 2019 00:58:09 -0400
Subject: [sdiy] How Do You Join The List?
In-Reply-To: <CAPR-mM_b2aTDEBgtFAKNsfcGViBMa+qb=s0quDhTkRFNcn0M8w@mail.gmail.com>
References: <CAPR-mM_b2aTDEBgtFAKNsfcGViBMa+qb=s0quDhTkRFNcn0M8w@mail.gmail.com>
Message-ID: <CA+wjhVsB3gpaN1kDd2TJoUBAiNvdDRUt+8FRapqz06ZcPBLJBw@mail.gmail.com>

The current list address (I recall it may have changed over the years,
and perhaps more than once over the decades) is Synth DIY
<synth-diy at synth-diy.org>. I went to the domain http://synth-diy.org
and found this statement. I presume it works, but you may want to try
it with another address to be sure.

"To subscribe point your browser to:
https://synth-diy.org/mailman/listinfo/synth-diy and follow
instructions."

On Sun, Sep 22, 2019 at 12:41 AM matrix <matrixsynth at gmail.com> wrote:
>
> Anyone know how to join the list nowadays?  The link at the bottom of http://search.retrosynth.com/synth-diy/index.html errors out.  Is there a new link?  I sometimes get people asking for SDIY advice.  For example, in the comments of this recent post: https://www.matrixsynth.com/2015/07/tiergrinder-tr-808-clone.html
>
> These requests rarely come in, so I hope it's OK to refer them here.  If not, let me know.
>
> --
>
> cheers,
> matrix
> http://www.matrixsynth.com
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy



From matrixsynth at gmail.com  Sun Sep 22 07:02:42 2019
From: matrixsynth at gmail.com (matrix)
Date: Sat, 21 Sep 2019 22:02:42 -0700
Subject: [sdiy] How Do You Join The List?
In-Reply-To: <CA+wjhVsB3gpaN1kDd2TJoUBAiNvdDRUt+8FRapqz06ZcPBLJBw@mail.gmail.com>
References: <CAPR-mM_b2aTDEBgtFAKNsfcGViBMa+qb=s0quDhTkRFNcn0M8w@mail.gmail.com>
 <CA+wjhVsB3gpaN1kDd2TJoUBAiNvdDRUt+8FRapqz06ZcPBLJBw@mail.gmail.com>
Message-ID: <CAPR-mM-49-vmib5dCYDX2fgtvg3Y7zcXf5YG+ynSvhHHQqQGzw@mail.gmail.com>

Thanks!  I will pass along the info.

On Sat, Sep 21, 2019 at 10:00 PM Ben Bradley <ben.pi.bradley at gmail.com>
wrote:

> The current list address (I recall it may have changed over the years,
> and perhaps more than once over the decades) is Synth DIY
> <synth-diy at synth-diy.org>. I went to the domain http://synth-diy.org
> and found this statement. I presume it works, but you may want to try
> it with another address to be sure.
>
> "To subscribe point your browser to:
> https://synth-diy.org/mailman/listinfo/synth-diy and follow
> instructions."
>
> On Sun, Sep 22, 2019 at 12:41 AM matrix <matrixsynth at gmail.com> wrote:
> >
> > Anyone know how to join the list nowadays?  The link at the bottom of
> http://search.retrosynth.com/synth-diy/index.html errors out.  Is there a
> new link?  I sometimes get people asking for SDIY advice.  For example, in
> the comments of this recent post:
> https://www.matrixsynth.com/2015/07/tiergrinder-tr-808-clone.html
> >
> > These requests rarely come in, so I hope it's OK to refer them here.  If
> not, let me know.
> >
> > --
> >
> > cheers,
> > matrix
> > http://www.matrixsynth.com
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>


-- 

cheers,
matrix
http://www.matrixsynth.com
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From chromatest at chromatest.net  Sun Sep 22 16:06:23 2019
From: chromatest at chromatest.net (Chromatest J. Pantsmaker)
Date: Sun, 22 Sep 2019 07:06:23 -0700
Subject: [sdiy] How Do You Join The List?
In-Reply-To: <CAPR-mM-49-vmib5dCYDX2fgtvg3Y7zcXf5YG+ynSvhHHQqQGzw@mail.gmail.com>
References: <CAPR-mM_b2aTDEBgtFAKNsfcGViBMa+qb=s0quDhTkRFNcn0M8w@mail.gmail.com>
 <CA+wjhVsB3gpaN1kDd2TJoUBAiNvdDRUt+8FRapqz06ZcPBLJBw@mail.gmail.com>
 <CAPR-mM-49-vmib5dCYDX2fgtvg3Y7zcXf5YG+ynSvhHHQqQGzw@mail.gmail.com>
Message-ID: <CADpm=3G722FBUEd2k+JdZrfKXpMMJNKxLB3xD1oUFdb9Vy6MHQ@mail.gmail.com>

That's also the info on the bottom of every email.
On Sep 21, 2019 10:04 PM, "matrix" <matrixsynth at gmail.com> wrote:

> Thanks!  I will pass along the info.
>
> On Sat, Sep 21, 2019 at 10:00 PM Ben Bradley <ben.pi.bradley at gmail.com>
> wrote:
>
>> The current list address (I recall it may have changed over the years,
>> and perhaps more than once over the decades) is Synth DIY
>> <synth-diy at synth-diy.org>. I went to the domain http://synth-diy.org
>> and found this statement. I presume it works, but you may want to try
>> it with another address to be sure.
>>
>> "To subscribe point your browser to:
>> https://synth-diy.org/mailman/listinfo/synth-diy and follow
>> instructions."
>>
>> On Sun, Sep 22, 2019 at 12:41 AM matrix <matrixsynth at gmail.com> wrote:
>> >
>> > Anyone know how to join the list nowadays?  The link at the bottom of
>> http://search.retrosynth.com/synth-diy/index.html errors out.  Is there
>> a new link?  I sometimes get people asking for SDIY advice.  For example,
>> in the comments of this recent post: https://www.matrixsynth.com/
>> 2015/07/tiergrinder-tr-808-clone.html
>> >
>> > These requests rarely come in, so I hope it's OK to refer them here.
>> If not, let me know.
>> >
>> > --
>> >
>> > cheers,
>> > matrix
>> > http://www.matrixsynth.com
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at synth-diy.org
>> > http://synth-diy.org/mailman/listinfo/synth-diy
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>>
>
>
> --
>
> cheers,
> matrix
> http://www.matrixsynth.com
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
>
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From ben at stuyts.nl  Mon Sep 23 15:23:38 2019
From: ben at stuyts.nl (Ben Stuyts)
Date: Mon, 23 Sep 2019 15:23:38 +0200
Subject: [sdiy] How Do You Join The List?
In-Reply-To: <CA+wjhVsB3gpaN1kDd2TJoUBAiNvdDRUt+8FRapqz06ZcPBLJBw@mail.gmail.com>
References: <CAPR-mM_b2aTDEBgtFAKNsfcGViBMa+qb=s0quDhTkRFNcn0M8w@mail.gmail.com>
 <CA+wjhVsB3gpaN1kDd2TJoUBAiNvdDRUt+8FRapqz06ZcPBLJBw@mail.gmail.com>
Message-ID: <1E5EAE53-EFD3-44E6-BEA2-71D4AD15DFEA@stuyts.nl>

Correct, https://synth-diy.org/mailman/listinfo/synth-diy is the url to use for subscribing. Let me know if there are any problems.

For searching/reading the archive of this list it is best to use our own link as it is complete from the beginning in 1995 till now: https://synth-diy.org/pipermail/synth-diy/

I?ll try to contact retrosynth.com <http://retrosynth.com/> to have them correct the link mentioned below.

Ben (co-moderator)

> On 22 Sep 2019, at 06:58, Ben Bradley <ben.pi.bradley at gmail.com> wrote:
> 
> The current list address (I recall it may have changed over the years,
> and perhaps more than once over the decades) is Synth DIY
> <synth-diy at synth-diy.org>. I went to the domain http://synth-diy.org
> and found this statement. I presume it works, but you may want to try
> it with another address to be sure.
> 
> "To subscribe point your browser to:
> https://synth-diy.org/mailman/listinfo/synth-diy and follow
> instructions."
> 
> On Sun, Sep 22, 2019 at 12:41 AM matrix <matrixsynth at gmail.com> wrote:
>> 
>> Anyone know how to join the list nowadays?  The link at the bottom of http://search.retrosynth.com/synth-diy/index.html errors out.  Is there a new link?  I sometimes get people asking for SDIY advice.  For example, in the comments of this recent post: https://www.matrixsynth.com/2015/07/tiergrinder-tr-808-clone.html
>> 
>> These requests rarely come in, so I hope it's OK to refer them here.  If not, let me know.
>> 
>> --
>> 
>> cheers,
>> matrix
>> http://www.matrixsynth.com
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy

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From ben.pi.bradley at gmail.com  Mon Sep 23 17:10:13 2019
From: ben.pi.bradley at gmail.com (Ben Bradley)
Date: Mon, 23 Sep 2019 11:10:13 -0400
Subject: [sdiy] How Do You Join The List?
In-Reply-To: <CADpm=3G722FBUEd2k+JdZrfKXpMMJNKxLB3xD1oUFdb9Vy6MHQ@mail.gmail.com>
References: <CAPR-mM_b2aTDEBgtFAKNsfcGViBMa+qb=s0quDhTkRFNcn0M8w@mail.gmail.com>
 <CA+wjhVsB3gpaN1kDd2TJoUBAiNvdDRUt+8FRapqz06ZcPBLJBw@mail.gmail.com>
 <CAPR-mM-49-vmib5dCYDX2fgtvg3Y7zcXf5YG+ynSvhHHQqQGzw@mail.gmail.com>
 <CADpm=3G722FBUEd2k+JdZrfKXpMMJNKxLB3xD1oUFdb9Vy6MHQ@mail.gmail.com>
Message-ID: <CA+wjhVue3o1m_1OL8RzL-AQ-vWXAEPvQRHo6hpBhFtf=eyNW1w@mail.gmail.com>

Now that you mention it, Gmail and perhaps others don't show that (or
signature lines or previous text below top-posting) automatically,
just the "..." link that I rarely bother to click on, as I assume I've
seen any info there in previous messages, so I usually don't see the
info tagged onto the end of messages. This is yet another
disappointing "feature" of modern email that leads to off-topic
discussions such as this one.

On Sun, Sep 22, 2019 at 10:07 AM Chromatest J. Pantsmaker
<chromatest at chromatest.net> wrote:
>
> That's also the info on the bottom of every email.
>
> On Sep 21, 2019 10:04 PM, "matrix" <matrixsynth at gmail.com> wrote:
>>
>> Thanks!  I will pass along the info.
>>
>> On Sat, Sep 21, 2019 at 10:00 PM Ben Bradley <ben.pi.bradley at gmail.com> wrote:
>>>
>>> The current list address (I recall it may have changed over the years,
>>> and perhaps more than once over the decades) is Synth DIY
>>> <synth-diy at synth-diy.org>. I went to the domain http://synth-diy.org
>>> and found this statement. I presume it works, but you may want to try
>>> it with another address to be sure.
>>>
>>> "To subscribe point your browser to:
>>> https://synth-diy.org/mailman/listinfo/synth-diy and follow
>>> instructions."
>>>
>>> On Sun, Sep 22, 2019 at 12:41 AM matrix <matrixsynth at gmail.com> wrote:
>>> >
>>> > Anyone know how to join the list nowadays?  The link at the bottom of http://search.retrosynth.com/synth-diy/index.html errors out.  Is there a new link?  I sometimes get people asking for SDIY advice.  For example, in the comments of this recent post: https://www.matrixsynth.com/2015/07/tiergrinder-tr-808-clone.html
>>> >
>>> > These requests rarely come in, so I hope it's OK to refer them here.  If not, let me know.
>>> >
>>> > --
>>> >
>>> > cheers,
>>> > matrix
>>> > http://www.matrixsynth.com
>>> > _______________________________________________
>>> > Synth-diy mailing list
>>> > Synth-diy at synth-diy.org
>>> > http://synth-diy.org/mailman/listinfo/synth-diy
>>>
>>> _______________________________________________
>>> Synth-diy mailing list
>>> Synth-diy at synth-diy.org
>>> http://synth-diy.org/mailman/listinfo/synth-diy
>>
>>
>>
>> --
>>
>> cheers,
>> matrix
>> http://www.matrixsynth.com
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy



From chromatest at azburners.org  Mon Sep 23 17:43:37 2019
From: chromatest at azburners.org (Chromatest J. Pantsmaker)
Date: Mon, 23 Sep 2019 08:43:37 -0700
Subject: [sdiy] How Do You Join The List?
In-Reply-To: <CA+wjhVue3o1m_1OL8RzL-AQ-vWXAEPvQRHo6hpBhFtf=eyNW1w@mail.gmail.com>
References: <CAPR-mM_b2aTDEBgtFAKNsfcGViBMa+qb=s0quDhTkRFNcn0M8w@mail.gmail.com>
 <CA+wjhVsB3gpaN1kDd2TJoUBAiNvdDRUt+8FRapqz06ZcPBLJBw@mail.gmail.com>
 <CAPR-mM-49-vmib5dCYDX2fgtvg3Y7zcXf5YG+ynSvhHHQqQGzw@mail.gmail.com>
 <CADpm=3G722FBUEd2k+JdZrfKXpMMJNKxLB3xD1oUFdb9Vy6MHQ@mail.gmail.com>
 <CA+wjhVue3o1m_1OL8RzL-AQ-vWXAEPvQRHo6hpBhFtf=eyNW1w@mail.gmail.com>
Message-ID: <CADpm=3EHVAfTA2xVfKrHA5qVBms3psm79OfebGxygYGV9sVoFw@mail.gmail.com>

It's easiest to see on the first message of a new email thread that
somebody else started.  It's not hidden by "..." on the first message.

On Mon, Sep 23, 2019 at 8:12 AM Ben Bradley <ben.pi.bradley at gmail.com>
wrote:

> Now that you mention it, Gmail and perhaps others don't show that (or
> signature lines or previous text below top-posting) automatically,
> just the "..." link that I rarely bother to click on, as I assume I've
> seen any info there in previous messages, so I usually don't see the
> info tagged onto the end of messages. This is yet another
> disappointing "feature" of modern email that leads to off-topic
> discussions such as this one.
>
> On Sun, Sep 22, 2019 at 10:07 AM Chromatest J. Pantsmaker
> <chromatest at chromatest.net> wrote:
> >
> > That's also the info on the bottom of every email.
> >
> > On Sep 21, 2019 10:04 PM, "matrix" <matrixsynth at gmail.com> wrote:
> >>
> >> Thanks!  I will pass along the info.
> >>
> >> On Sat, Sep 21, 2019 at 10:00 PM Ben Bradley <ben.pi.bradley at gmail.com>
> wrote:
> >>>
> >>> The current list address (I recall it may have changed over the years,
> >>> and perhaps more than once over the decades) is Synth DIY
> >>> <synth-diy at synth-diy.org>. I went to the domain http://synth-diy.org
> >>> and found this statement. I presume it works, but you may want to try
> >>> it with another address to be sure.
> >>>
> >>> "To subscribe point your browser to:
> >>> https://synth-diy.org/mailman/listinfo/synth-diy and follow
> >>> instructions."
> >>>
> >>> On Sun, Sep 22, 2019 at 12:41 AM matrix <matrixsynth at gmail.com> wrote:
> >>> >
> >>> > Anyone know how to join the list nowadays?  The link at the bottom
> of http://search.retrosynth.com/synth-diy/index.html errors out.  Is
> there a new link?  I sometimes get people asking for SDIY advice.  For
> example, in the comments of this recent post:
> https://www.matrixsynth.com/2015/07/tiergrinder-tr-808-clone.html
> >>> >
> >>> > These requests rarely come in, so I hope it's OK to refer them
> here.  If not, let me know.
> >>> >
> >>> > --
> >>> >
> >>> > cheers,
> >>> > matrix
> >>> > http://www.matrixsynth.com
> >>> > _______________________________________________
> >>> > Synth-diy mailing list
> >>> > Synth-diy at synth-diy.org
> >>> > http://synth-diy.org/mailman/listinfo/synth-diy
> >>>
> >>> _______________________________________________
> >>> Synth-diy mailing list
> >>> Synth-diy at synth-diy.org
> >>> http://synth-diy.org/mailman/listinfo/synth-diy
> >>
> >>
> >>
> >> --
> >>
> >> cheers,
> >> matrix
> >> http://www.matrixsynth.com
> >>
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at synth-diy.org
> >> http://synth-diy.org/mailman/listinfo/synth-diy
> >>
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
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From quincas at gmail.com  Tue Sep 24 18:27:01 2019
From: quincas at gmail.com (Quincas Moreira)
Date: Tue, 24 Sep 2019 11:27:01 -0500
Subject: [sdiy] A couple of fun videos from Georgia Tech students
In-Reply-To: <2C76A838-9B07-408A-83C6-5BCE79CB3F1B@ece.gatech.edu>
References: <2C76A838-9B07-408A-83C6-5BCE79CB3F1B@ece.gatech.edu>
Message-ID: <CA+u0JtmzUqYoK5Ke5s=TQsDcGNJswu32hyO_Y8tnkOMarEodEg@mail.gmail.com>

These are super cool!

On Mon, Aug 26, 2019 at 12:04 AM Lanterman, Aaron <lanterma at ece.gatech.edu>
wrote:

> Using a neural network to combine waveforms:
>
> https://www.youtube.com/watch?v=iKDiE9ARdZ4
>
> Korg Delta VCF my synth class students built:
>
> https://www.youtube.com/watch?v=WhfRX3rTmtk
>
> ?????????
>
> Aaron Lanterman, Prof. of ECE, Georgia Tech
> My blog on Education and Innovation: https://edupocalypsenow.wordpress.com
> My blog on Electronics and Programming: https://lantertronics.blogspot.com
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>


-- 
[image: QMA]

Quincas Moreira
Director | QMA
mobile:  5534988825
site:  quincasmoreira.com
email:  quincas at gmail.com
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From didierleplae at yahoo.com  Tue Sep 24 18:34:25 2019
From: didierleplae at yahoo.com (Didier Leplae)
Date: Tue, 24 Sep 2019 11:34:25 -0500
Subject: [sdiy] A couple of fun videos from Georgia Tech students
In-Reply-To: <CA+u0JtmzUqYoK5Ke5s=TQsDcGNJswu32hyO_Y8tnkOMarEodEg@mail.gmail.com>
References: <2C76A838-9B07-408A-83C6-5BCE79CB3F1B@ece.gatech.edu>
 <CA+u0JtmzUqYoK5Ke5s=TQsDcGNJswu32hyO_Y8tnkOMarEodEg@mail.gmail.com>
Message-ID: <4181D127-5A3F-495E-BF33-FEBD177772B3@yahoo.com>

Is this similar to the google NSynth?

https://nsynthsuper.withgoogle.com/

> On Sep 24, 2019, at 11:27 AM, Quincas Moreira <quincas at gmail.com> wrote:
> 
> These are super cool!
> 
>> On Mon, Aug 26, 2019 at 12:04 AM Lanterman, Aaron <lanterma at ece.gatech.edu> wrote:
>> Using a neural network to combine waveforms:
>> 
>> https://www.youtube.com/watch?v=iKDiE9ARdZ4
>> 
>> Korg Delta VCF my synth class students built:
>> 
>> https://www.youtube.com/watch?v=WhfRX3rTmtk
>> 
>> ?????????
>> 
>> Aaron Lanterman, Prof. of ECE, Georgia Tech
>> My blog on Education and Innovation: https://edupocalypsenow.wordpress.com
>> My blog on Electronics and Programming: https://lantertronics.blogspot.com
>> 
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
> 
> 
> -- 
> 	
> Quincas Moreira
> Director | QMA
> mobile:  5534988825
> site:  quincasmoreira.com
> email:  quincas at gmail.com
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
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From jason at redfish.net  Tue Sep 24 19:18:48 2019
From: jason at redfish.net (Jason Proctor)
Date: Tue, 24 Sep 2019 10:18:48 -0700
Subject: [sdiy] A couple of fun videos from Georgia Tech students
In-Reply-To: <4181D127-5A3F-495E-BF33-FEBD177772B3@yahoo.com>
References: <2C76A838-9B07-408A-83C6-5BCE79CB3F1B@ece.gatech.edu>
 <CA+u0JtmzUqYoK5Ke5s=TQsDcGNJswu32hyO_Y8tnkOMarEodEg@mail.gmail.com>
 <4181D127-5A3F-495E-BF33-FEBD177772B3@yahoo.com>
Message-ID: <CALQanA+ThCxOchdPW83Fehvq2No+z-gJEs_FW_n1WxVgE==4sA@mail.gmail.com>

NSynth = vector synthesis ;-)


On Tue, Sep 24, 2019 at 9:41 AM Didier Leplae via Synth-diy <
synth-diy at synth-diy.org> wrote:

> Is this similar to the google NSynth?
>
> https://nsynthsuper.withgoogle.com/
>
> On Sep 24, 2019, at 11:27 AM, Quincas Moreira <quincas at gmail.com> wrote:
>
> These are super cool!
>
> On Mon, Aug 26, 2019 at 12:04 AM Lanterman, Aaron <lanterma at ece.gatech.edu>
> wrote:
>
>> Using a neural network to combine waveforms:
>>
>> https://www.youtube.com/watch?v=iKDiE9ARdZ4
>>
>> Korg Delta VCF my synth class students built:
>>
>> https://www.youtube.com/watch?v=WhfRX3rTmtk
>>
>> ?????????
>>
>> Aaron Lanterman, Prof. of ECE, Georgia Tech
>> My blog on Education and Innovation:
>> https://edupocalypsenow.wordpress.com
>> My blog on Electronics and Programming:
>> https://lantertronics.blogspot.com
>>
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
>>
>
>
> --
> [image: QMA]
>
> Quincas Moreira
> Director | QMA
> mobile:  5534988825
> site:  quincasmoreira.com
> email:  quincas at gmail.com
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
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From eric at ericframpton.com  Thu Sep 26 00:44:49 2019
From: eric at ericframpton.com (Eric Frampton)
Date: Wed, 25 Sep 2019 18:44:49 -0400
Subject: [sdiy] Prophet-5 help?
In-Reply-To: <a1efbf06-fd5f-4cb7-d3f0-321494a40efe@musictechnologiesgroup.com>
References: <F596B174-ADDA-40E5-858C-9A05A659622A@ericframpton.com>
 <3467AF43-F78C-4737-AC10-64B7EDDE28D3@audiobanshee.com>
 <238CAEC7-7B61-4392-B6DD-99E15BA6CFC1@ericframpton.com>
 <a1efbf06-fd5f-4cb7-d3f0-321494a40efe@musictechnologiesgroup.com>
Message-ID: <CD78115B-2F54-43BB-A854-71DDB7F026BB@ericframpton.com>

An update:

After receiving a new set of 8.2 EPROMs from a fellow listmember (thanks G!), the unit now appears to drop in and out of Record mode as it should.

Now however, if I create a preset by hand and try to save it to a patch location, it goes through the Record routine, but either isn?t getting saved correctly or isn?t getting recalled correctly.

If I attempt to load cassette data (I?ve tried files that I know have worked in other P-5?s), I can?t get the cassette load to complete (it always ends with a flashing LOAD LED) and, while there *is* data being loaded into memory, it always comes up scrambled. If I do repeated cassette loads and listen to the scrambled patches, they?re different after each load attempt.

When I recall these incorrect patches, all programmable latches/front panel buttons are set ON for every patch, it?s only the pot values that seem to be changing. The same behavior happens when I write/recall a patch that I?ve manually created - the pot values are correct, the latches are wrong (all switches are on).

e




From tom at electricdruid.net  Thu Sep 26 11:36:45 2019
From: tom at electricdruid.net (Tom Wiltshire)
Date: Thu, 26 Sep 2019 10:36:45 +0100
Subject: [sdiy] Prophet-5 help?
In-Reply-To: <CD78115B-2F54-43BB-A854-71DDB7F026BB@ericframpton.com>
References: <F596B174-ADDA-40E5-858C-9A05A659622A@ericframpton.com>
 <3467AF43-F78C-4737-AC10-64B7EDDE28D3@audiobanshee.com>
 <238CAEC7-7B61-4392-B6DD-99E15BA6CFC1@ericframpton.com>
 <a1efbf06-fd5f-4cb7-d3f0-321494a40efe@musictechnologiesgroup.com>
 <CD78115B-2F54-43BB-A854-71DDB7F026BB@ericframpton.com>
Message-ID: <88E11091-CD99-4E0A-A81D-98B78F1CBE90@electricdruid.net>

If the pots are working, but the switches are not, what?s the difference between those two parts of the system?

The 4051?s that demux the CVs have their address lines driven by the same 14174 latches that control the switched functions (Program Latches 0,1,2), so why would so work and some not? The Gates are driven off the same set of latches too, so if the gates work, at least some of those latches are ok.

If the buttons affect the LEDs when you?re programming the synth, then the processor must be able to _read_ the switches and _write_ to the LEDs. If that?s not the case, the problem could be the 4514 decoder that reads the button states.

I?m assuming this is a hardware issue. It could still be firmware, if there was a significant revision of the pin-out somewhere, so that a newer firmware uses a different pins a select line, say.

It?s an interesting problem!

Tom

==================
       Electric Druid
Synth & Stompbox DIY
==================

> On 25 Sep 2019, at 23:44, Eric Frampton <eric at ericframpton.com> wrote:
> 
> An update:
> 
> After receiving a new set of 8.2 EPROMs from a fellow listmember (thanks G!), the unit now appears to drop in and out of Record mode as it should.
> 
> Now however, if I create a preset by hand and try to save it to a patch location, it goes through the Record routine, but either isn?t getting saved correctly or isn?t getting recalled correctly.
> 
> If I attempt to load cassette data (I?ve tried files that I know have worked in other P-5?s), I can?t get the cassette load to complete (it always ends with a flashing LOAD LED) and, while there *is* data being loaded into memory, it always comes up scrambled. If I do repeated cassette loads and listen to the scrambled patches, they?re different after each load attempt.
> 
> When I recall these incorrect patches, all programmable latches/front panel buttons are set ON for every patch, it?s only the pot values that seem to be changing. The same behavior happens when I write/recall a patch that I?ve manually created - the pot values are correct, the latches are wrong (all switches are on).
> 
> e
> 
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy




From quincas at gmail.com  Thu Sep 26 19:40:34 2019
From: quincas at gmail.com (Quincas Moreira)
Date: Thu, 26 Sep 2019 12:40:34 -0500
Subject: [sdiy] Video of 4-pole VCF using custom "vactrol"
In-Reply-To: <04F40174-A0C2-4357-B3EE-9A5082106968@ece.gatech.edu>
References: <04F40174-A0C2-4357-B3EE-9A5082106968@ece.gatech.edu>
Message-ID: <CA+u0Jtn0Lm+0UEe1BQkL4014qimHb8UJysPkjk6K8wjxAt=uDQ@mail.gmail.com>

Aaron, I'd love to see a schematics for this! The most popular video on my
channel is the one on a home made vactrol based LPG, one on a 4-pole filter
would be a great followup!
https://youtu.be/8BOnvSQpoGY

On Mon, Aug 26, 2019 at 1:48 AM Lanterman, Aaron <lanterma at ece.gatech.edu>
wrote:

> Designed and built by my students way back in 2015 (yes, I have e-mail
> that old that I?m working my way through)
>
> https://www.youtube.com/watch?v=5ysI6wSXW4k
>
> Down to 914 messages in my in box! (Major progress, since I started with
> 6,000+)?.
>
> Aaron Lanterman, Prof. of ECE, Georgia Tech
> My blog on Education and Innovation: https://edupocalypsenow.wordpress.com
> My blog on Electronics and Programming: https://lantertronics.blogspot.com
>
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>


-- 
[image: QMA]

Quincas Moreira
Director | QMA
mobile:  5534988825
site:  quincasmoreira.com
email:  quincas at gmail.com
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From barryklein at cox.net  Thu Sep 26 20:17:31 2019
From: barryklein at cox.net (Barry Klein)
Date: Thu, 26 Sep 2019 11:17:31 -0700
Subject: [sdiy] 8038?
Message-ID: <4E4132FE-8E6D-4496-BACA-255C4F62ACFF@cox.net>

I see some kits using the ?icl8038?.  Are these using old stock of parts or has the IC been resurrected by someone?


Barry



From jarno.verhoeven at ziggo.nl  Thu Sep 26 20:33:33 2019
From: jarno.verhoeven at ziggo.nl (jarno.verhoeven)
Date: Thu, 26 Sep 2019 20:33:33 +0200
Subject: [sdiy] 8038?
In-Reply-To: <4E4132FE-8E6D-4496-BACA-255C4F62ACFF@cox.net>
Message-ID: <201909261833.x8QIXc1k022952@dropmix.synth-diy.org>

Was wondering the same thing about the xr2206 based kits...JarnoVerzonden vanaf mijn Samsung Galaxy-smartphone.
-------- Oorspronkelijk bericht --------Van: Barry Klein <barryklein at cox.net> Datum: 26-09-19  20:17  (GMT+01:00) Aan: synth-diy at synth-diy.org Onderwerp: [sdiy] 8038? I see some kits using the ?icl8038?.? Are these using old stock of parts or has the IC been resurrected by someone?Barry_______________________________________________Synth-diy mailing listSynth-diy at synth-diy.orghttp://synth-diy.org/mailman/listinfo/synth-diy
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From ben.pi.bradley at gmail.com  Thu Sep 26 22:33:06 2019
From: ben.pi.bradley at gmail.com (Ben Bradley)
Date: Thu, 26 Sep 2019 16:33:06 -0400
Subject: [sdiy] 8038?
In-Reply-To: <201909261833.x8QIXc1k022952@dropmix.synth-diy.org>
References: <4E4132FE-8E6D-4496-BACA-255C4F62ACFF@cox.net>
 <201909261833.x8QIXc1k022952@dropmix.synth-diy.org>
Message-ID: <CA+wjhVtHmifU3YJAB7QkEYRGPod8NP+sE8jf33h-RW0wpWVTag@mail.gmail.com>

>From what I've seen, the current XR2206 chips are cheap knockoffs that
won't operate over the full specs of the original, and unless proven
otherwise I'd suspect the same about similar resurrections.

See the SDIY thread titled "NE566 Boon" started Feb 24, 2018.


On Thu, Sep 26, 2019 at 2:34 PM jarno.verhoeven
<jarno.verhoeven at ziggo.nl> wrote:
>
> Was wondering the same thing about the xr2206 based kits...
>
> Jarno
>
>
>
> Verzonden vanaf mijn Samsung Galaxy-smartphone.
>
> -------- Oorspronkelijk bericht --------
> Van: Barry Klein <barryklein at cox.net>
> Datum: 26-09-19 20:17 (GMT+01:00)
> Aan: synth-diy at synth-diy.org
> Onderwerp: [sdiy] 8038?
>
> I see some kits using the ?icl8038?.  Are these using old stock of parts or has the IC been resurrected by someone?
>
>
> Barry
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy



From sdiy-mz01 at blauwurf.info  Sun Sep 29 13:54:42 2019
From: sdiy-mz01 at blauwurf.info (Michael Zacherl)
Date: Sun, 29 Sep 2019 13:54:42 +0200
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions?
Message-ID: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>

Hi, just got a flyer offering this for ?40:

https://www.neuhold-elektronik.at/datenblatt/N3026_An.pdf

googlish: https://translate.google.at/translate?sl=auto&tl=en&u=https%3A%2F%2Fwww.neuhold-elektronik.at%2Fdatenblatt%2FN3026_An.pdf

Is this any good?

Thanks, Michael.


From sdiy-mz01 at blauwurf.info  Sun Sep 29 13:58:57 2019
From: sdiy-mz01 at blauwurf.info (Michael Zacherl)
Date: Sun, 29 Sep 2019 13:58:57 +0200
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions? (w/ english
 link)
In-Reply-To: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
References: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
Message-ID: <161F55FB-F999-463E-866C-62EB861F0684@blauwurf.info>


> On 29 Sep 2019, at 13:54, Michael Zacherl <sdiy-mz01 at blauwurf.info> wrote:
> 
> Hi, just got a flyer offering this for ?40:
> 
> https://www.neuhold-elektronik.at/datenblatt/N3026_An.pdf
> 
> googlish: https://translate.google.at/translate?sl=auto&tl=en&u=https%3A%2F%2Fwww.neuhold-elektronik.at%2Fdatenblatt%2FN3026_An.pdf

Better: https://www.joy-it.net/en/products/JT-DPS5005

> 
> Is this any good?
> 
> Thanks, Michael.





From igg.debus at gmail.com  Sun Sep 29 14:30:12 2019
From: igg.debus at gmail.com (Ingo Debus)
Date: Sun, 29 Sep 2019 14:30:12 +0200
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions? (w/ english
 link)
In-Reply-To: <161F55FB-F999-463E-866C-62EB861F0684@blauwurf.info>
References: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
 <161F55FB-F999-463E-866C-62EB861F0684@blauwurf.info>
Message-ID: <8D0DE108-B7EC-43D8-98C9-79C4275D5378@gmail.com>


> Am 29.09.2019 um 13:58 schrieb Michael Zacherl <sdiy-mz01 at blauwurf.info>:
> 
> 
>> On 29 Sep 2019, at 13:54, Michael Zacherl <sdiy-mz01 at blauwurf.info> wrote:
>> 
>> Hi, just got a flyer offering this for ?40:
>> 
>> https://www.neuhold-elektronik.at/datenblatt/N3026_An.pdf
>> 
>> googlish: https://translate.google.at/translate?sl=auto&tl=en&u=https%3A%2F%2Fwww.neuhold-elektronik.at%2Fdatenblatt%2FN3026_An.pdf
> 
> Better: https://www.joy-it.net/en/products/JT-DPS5005
> 
>> 
>> Is this any good?

Here?s a review (in German):
https://www.elektormagazine.de/news/review-programmierbares-labor-netzteil-joy-it-dps5005

If you buy one, let us know about your experiences!

Ingo


From rburnett at richieburnett.co.uk  Sun Sep 29 18:08:15 2019
From: rburnett at richieburnett.co.uk (Richie Burnett)
Date: Sun, 29 Sep 2019 17:08:15 +0100
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions? (w/ english
 link)
In-Reply-To: <8D0DE108-B7EC-43D8-98C9-79C4275D5378@gmail.com>
References: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
 <161F55FB-F999-463E-866C-62EB861F0684@blauwurf.info>
 <8D0DE108-B7EC-43D8-98C9-79C4275D5378@gmail.com>
Message-ID: <2gly8ki3f35t61ckcl2fugy9.1569773295830@email.android.com>

I would be very wary Michael. 

The picture of the test setup in that German "review" makes me cringe...

https://cdn.xingosoftware.com/elektor/images/fetch/dpr_1,w_720/https%3A%2F%2Fwww.elektormagazine.de%2Fassets%2Fupload%2Fimages%2F42%2F20190523105317_JT-DPS-5005-JT-DPS-Case-test2.jpg

Live (hot) and neutral connections crossed over and no earth connection on a metal-cased mains (line) fed power supply. Very dangerous, particularly if someone can touch the output leads.

-Richie, 


---- Ingo Debus wrote ----

>
>> Am 29.09.2019 um 13:58 schrieb Michael Zacherl <sdiy-mz01 at blauwurf.info>:
>> 
>> 
>>> On 29 Sep 2019, at 13:54, Michael Zacherl <sdiy-mz01 at blauwurf.info> wrote:
>>> 
>>> Hi, just got a flyer offering this for ?40:
>>> 
>>> https://www.neuhold-elektronik.at/datenblatt/N3026_An.pdf
>>> 
>>> googlish: https://translate.google.at/translate?sl=auto&tl=en&u=https%3A%2F%2Fwww.neuhold-elektronik.at%2Fdatenblatt%2FN3026_An.pdf
>> 
>> Better: https://www.joy-it.net/en/products/JT-DPS5005
>> 
>>> 
>>> Is this any good?
>
>Here?s a review (in German):
>https://www.elektormagazine.de/news/review-programmierbares-labor-netzteil-joy-it-dps5005
>
>If you buy one, let us know about your experiences!
>
>Ingo
>_______________________________________________
>Synth-diy mailing list
>Synth-diy at synth-diy.org
>http://synth-diy.org/mailman/listinfo/synth-diy



From per.mattsson at miun.se  Sun Sep 29 19:32:48 2019
From: per.mattsson at miun.se (Mattsson, Per)
Date: Sun, 29 Sep 2019 17:32:48 +0000
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions?
In-Reply-To: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
References: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
Message-ID: <0C929444-3D9F-412C-8488-81C5EB5FD3EA@miun.se>

Hi, I have two of these, I have no problems whatsoever.

There is also this:

https://johan.kanflo.com/hacking-the-dps5005/

regards

Skickat fr?n min iPhone

29 sep. 2019 kl. 14:03 skrev Michael Zacherl <sdiy-mz01 at blauwurf.info>:

?Hi, just got a flyer offering this for ?40:

https://www.neuhold-elektronik.at/datenblatt/N3026_An.pdf

googlish: https://translate.google.at/translate?sl=auto&tl=en&u=https%3A%2F%2Fwww.neuhold-elektronik.at%2Fdatenblatt%2FN3026_An.pdf

Is this any good?

Thanks, Michael.
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From igg.debus at gmail.com  Sun Sep 29 21:02:53 2019
From: igg.debus at gmail.com (Ingo Debus)
Date: Sun, 29 Sep 2019 21:02:53 +0200
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions? (w/ english
 link)
In-Reply-To: <2gly8ki3f35t61ckcl2fugy9.1569773295830@email.android.com>
References: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
 <161F55FB-F999-463E-866C-62EB861F0684@blauwurf.info>
 <8D0DE108-B7EC-43D8-98C9-79C4275D5378@gmail.com>
 <2gly8ki3f35t61ckcl2fugy9.1569773295830@email.android.com>
Message-ID: <A6DB8985-62B9-48B7-8123-EC07A52B5EA8@gmail.com>


> Am 29.09.2019 um 18:08 schrieb Richie Burnett <rburnett at richieburnett.co.uk>:
> 
> The picture of the test setup in that German "review" makes me cringe...
> 
> https://cdn.xingosoftware.com/elektor/images/fetch/dpr_1,w_720/https%3A%2F%2Fwww.elektormagazine.de%2Fassets%2Fupload%2Fimages%2F42%2F20190523105317_JT-DPS-5005-JT-DPS-Case-test2.jpg
> 
> Live (hot) and neutral connections crossed over and no earth connection on a metal-cased mains (line) fed power supply. Very dangerous, particularly if someone can touch the output leads.

Bummer! They didn?t connect the power supply to earth!

But then, the power supply on the left side of the picture isn?t part of the kit that is reviewed.

Ingo


From wonggster at gmail.com  Mon Sep 30 04:03:25 2019
From: wonggster at gmail.com (gino wong)
Date: Sun, 29 Sep 2019 22:03:25 -0400
Subject: [sdiy] Mike Peake u there ?
Message-ID: <CAMZJ4emdXZ-uNJdCYs=TY-+93eJLpeVGzh5UDK6_ubCS4+QV4w@mail.gmail.com>

Mike Peake, I need to get in touch with you

Hope you are well

Gino

-- 
*Gino Wong Birgelo*
*Senior Producer *ReRed Recording Int
*ginowong at gmail.com <ginowong at gmail.com> *
vox
215 200 3756
Skype
*215 717 7059*
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From sdiy-mz01 at blauwurf.info  Mon Sep 30 06:21:35 2019
From: sdiy-mz01 at blauwurf.info (Michael Zacherl)
Date: Mon, 30 Sep 2019 06:21:35 +0200
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions? (w/ english
 link)
In-Reply-To: <8D0DE108-B7EC-43D8-98C9-79C4275D5378@gmail.com>
References: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
 <161F55FB-F999-463E-866C-62EB861F0684@blauwurf.info>
 <8D0DE108-B7EC-43D8-98C9-79C4275D5378@gmail.com>
Message-ID: <337BF674-A148-4BDB-B337-0338108FBF19@blauwurf.info>


> On 29 Sep 2019, at 14:30, Ingo Debus <igg.debus at gmail.com> wrote:
> 
>>> 
>>> Is this any good?
> 
> Here?s a review (in German):
> https://www.elektormagazine.de/news/review-programmierbares-labor-netzteil-joy-it-dps5005

thanks, not very deep but providing some insight.

Alas this retailer I got the offer from just provides the DPS5005, no cases whatsoever.
But lets see.
m.




From sdiy-mz01 at blauwurf.info  Mon Sep 30 06:28:25 2019
From: sdiy-mz01 at blauwurf.info (Michael Zacherl)
Date: Mon, 30 Sep 2019 06:28:25 +0200
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions? (w/ english
 link)
In-Reply-To: <2gly8ki3f35t61ckcl2fugy9.1569773295830@email.android.com>
References: <B4A3DE43-E13D-4F30-AEBE-860CFD37DF46@blauwurf.info>
 <161F55FB-F999-463E-866C-62EB861F0684@blauwurf.info>
 <8D0DE108-B7EC-43D8-98C9-79C4275D5378@gmail.com>
 <2gly8ki3f35t61ckcl2fugy9.1569773295830@email.android.com>
Message-ID: <A5C46735-E62E-4152-A5FE-FBA42BD35C10@blauwurf.info>

Hi Richie,

> On 29 Sep 2019, at 18:08, Richie Burnett <rburnett at richieburnett.co.uk> wrote:
> 
> I would be very wary Michael. 
> 
> The picture of the test setup in that German "review" makes me cringe?

not my style either! ;)  (my wires would be more messy) (just kidding - not?) ;)

> https://cdn.xingosoftware.com/elektor/images/fetch/dpr_1,w_720/https%3A%2F%2Fwww.elektormagazine.de%2Fassets%2Fupload%2Fimages%2F42%2F20190523105317_JT-DPS-5005-JT-DPS-Case-test2.jpg

I?m concerned about stability, HF-noise and such.

And I had bad experiences with switched mode PSUs. 

ATM I?m rather fighting time constraints, to prevent having this things sitting around for months after getting them. :(

Thanks, m.

> ---- Ingo Debus wrote ----
> 
>> 
>>> Am 29.09.2019 um 13:58 schrieb Michael Zacherl <sdiy-mz01 at blauwurf.info>:
>>> 
>>> 
>>>> On 29 Sep 2019, at 13:54, Michael Zacherl <sdiy-mz01 at blauwurf.info> wrote:
>>>> 
>>>> Hi, just got a flyer offering this for ?40:
>>>> 
>>>> https://www.neuhold-elektronik.at/datenblatt/N3026_An.pdf
>>>> 
>>>> googlish: https://translate.google.at/translate?sl=auto&tl=en&u=https%3A%2F%2Fwww.neuhold-elektronik.at%2Fdatenblatt%2FN3026_An.pdf
>>> 
>>> Better: https://www.joy-it.net/en/products/JT-DPS5005
>>> 
>>>> 
>>>> Is this any good?
>> 
>> Here?s a review (in German):
>> https://www.elektormagazine.de/news/review-programmierbares-labor-netzteil-joy-it-dps5005





From jarno.verhoeven at ziggo.nl  Mon Sep 30 07:26:42 2019
From: jarno.verhoeven at ziggo.nl (jarno.verhoeven)
Date: Mon, 30 Sep 2019 07:26:42 +0200
Subject: [sdiy] Mike Peake u there ?
In-Reply-To: <CAMZJ4emdXZ-uNJdCYs=TY-+93eJLpeVGzh5UDK6_ubCS4+QV4w@mail.gmail.com>
Message-ID: <201909300526.x8U5Qm8G019063@dropmix.synth-diy.org>

He has been on Muffwiggler today, last post yesterday.Verzonden vanaf mijn Samsung Galaxy-smartphone.
-------- Oorspronkelijk bericht --------Van: gino wong <wonggster at gmail.com> Datum: 30-09-19  04:03  (GMT+01:00) Aan: Synth-diy at synth-diy.org Onderwerp: [sdiy] Mike Peake u there ? Mike Peake, I need to get in touch with youHope you are wellGino-- Gino Wong BirgeloSenior Producer?ReRed Recording Intginowong at gmail.com?vox215 200 3756Skype215 717 7059
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From Peter.Ullrich at kapsch.net  Mon Sep 30 07:57:05 2019
From: Peter.Ullrich at kapsch.net (Ullrich Peter)
Date: Mon, 30 Sep 2019 05:57:05 +0000
Subject: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions? (w/ english
 link)
Message-ID: <AM0PR03MB55696E3869EDE7749FE767C394820@AM0PR03MB5569.eurprd03.prod.outlook.com>

Hi Michael!

And if you have some time (6 to 8 weeks) you can buy it cheaper from Banggood:
https://www.banggood.com/search/dps5005.html?from=nav

Ciao
Peter

-----Urspr?ngliche Nachricht-----
Von: Synth-diy <synth-diy-bounces at synth-diy.org> Im Auftrag von Michael Zacherl
Gesendet: Montag, 30. September 2019 06:28
An: synth-diy mailing list <synth-diy at synth-diy.org>
Betreff: Re: [sdiy] [semi OT] adjustable DC-DC PSU - Opinions? (w/ english link)

Hi Richie,

> On 29 Sep 2019, at 18:08, Richie Burnett <rburnett at richieburnett.co.uk> wrote:
>
> I would be very wary Michael.
>
> The picture of the test setup in that German "review" makes me cringe?

not my style either! ;)  (my wires would be more messy) (just kidding - not?) ;)

> https://cdn.xingosoftware.com/elektor/images/fetch/dpr_1,w_720/https%3A%2F%2Fwww.elektormagazine.de%2Fassets%2Fupload%2Fimages%2F42%2F20190523105317_JT-DPS-5005-JT-DPS-Case-test2.jpg

I?m concerned about stability, HF-noise and such.

And I had bad experiences with switched mode PSUs.

ATM I?m rather fighting time constraints, to prevent having this things sitting around for months after getting them. :(

Thanks, m.

> ---- Ingo Debus wrote ----
>
>>
>>> Am 29.09.2019 um 13:58 schrieb Michael Zacherl <sdiy-mz01 at blauwurf.info>:
>>>
>>>
>>>> On 29 Sep 2019, at 13:54, Michael Zacherl <sdiy-mz01 at blauwurf.info> wrote:
>>>>
>>>> Hi, just got a flyer offering this for ?40:
>>>>
>>>> https://www.neuhold-elektronik.at/datenblatt/N3026_An.pdf
>>>>
>>>> googlish: https://translate.google.at/translate?sl=auto&tl=en&u=https%3A%2F%2Fwww.neuhold-elektronik.at%2Fdatenblatt%2FN3026_An.pdf
>>>
>>> Better: https://www.joy-it.net/en/products/JT-DPS5005
>>>
>>>>
>>>> Is this any good?
>>
>> Here?s a review (in German):
>> https://www.elektormagazine.de/news/review-programmierbares-labor-netzteil-joy-it-dps5005



_______________________________________________
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Synth-diy at synth-diy.org
http://synth-diy.org/mailman/listinfo/synth-diy



The information contained in this e-mail message is privileged and confidential and is for the exclusive use of the addressee. The person who receives this message and who is not the addressee, one of his employees or an agent entitled to hand it over to the addressee, is informed that he may not use, disclose or reproduce the contents thereof, and is kindly asked to notify the sender and delete the e-mail immediately.




From rburnett at richieburnett.co.uk  Mon Sep 30 12:23:40 2019
From: rburnett at richieburnett.co.uk (Richie Burnett)
Date: Mon, 30 Sep 2019 11:23:40 +0100
Subject: [sdiy] Novation Peak FPGA ?
Message-ID: <A4148920A738451F8B6B1449270F42B0@RICHIEPC>

Out of interest does anyone know what FPGA novation use in their Peak and 
Summit synths?

-Richie, 



From ulfurh at gmail.com  Mon Sep 30 16:59:15 2019
From: ulfurh at gmail.com (ulfur hansson)
Date: Mon, 30 Sep 2019 10:59:15 -0400
Subject: [sdiy] experience with AD5669
Message-ID: <CAG9O7x2DU4jWwf8jW5HcXQ3D4XWRrHa2tXTVOfBQ-0MGMa2gZA@mail.gmail.com>

hello list -

has anyone tried the rather expensive AD5669 DAC for generating multiple
audio rate oscillations?

looking at the new teensy 4.0 its tempting to try daisy chaining two of
these DAC's for 16 midi controlled oscillator outputs at once...

i'd love to hear your your thoughts on these, especially when compared to
other DAC's such as the DAC8568C (which offers no i2C!) - it'd be a great
platform to build a semi analog polysynth.

all the best,
-?lfur

-- 
?
ulfurhansson.com
cargocollective.com/ulfur
instagram.com/ulfur_
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From synth at schmitzbits.de  Mon Sep 30 17:44:24 2019
From: synth at schmitzbits.de (=?UTF-8?Q?Ren=c3=a9_Schmitz?=)
Date: Mon, 30 Sep 2019 17:44:24 +0200
Subject: [sdiy] experience with AD5669
In-Reply-To: <CAG9O7x2DU4jWwf8jW5HcXQ3D4XWRrHa2tXTVOfBQ-0MGMa2gZA@mail.gmail.com>
References: <CAG9O7x2DU4jWwf8jW5HcXQ3D4XWRrHa2tXTVOfBQ-0MGMa2gZA@mail.gmail.com>
Message-ID: <d2c78df0-604e-5c04-d116-eb92e2422821@schmitzbits.de>

Dear ?lfur,

I would say the 5669 has a bottleneck, being the I2C interface.
At it's nominal 400kHz you can't shovel 16Bits at 44kHz for even a 
single channel, let alone 8. The SPI of the 8568 would be my choice here.

Best,
  Ren?

--
synth at schmitzbits.de
http://schmitzbits.de


From eric.schlappi at gmail.com  Mon Sep 30 21:41:46 2019
From: eric.schlappi at gmail.com (Eric Schlappi)
Date: Mon, 30 Sep 2019 12:41:46 -0700
Subject: [sdiy] Novation Peak FPGA ?
In-Reply-To: <A4148920A738451F8B6B1449270F42B0@RICHIEPC>
References: <A4148920A738451F8B6B1449270F42B0@RICHIEPC>
Message-ID: <CANBp-JwzZeem3CeiXAPiBYbzws2p=NrdMAd3HTReQVFVRQzHqA@mail.gmail.com>

I do not know what the Peak uses but I've been experimenting with an fpga
based synthesizer using open source tools on the Lattice ICE40. Support is
also available for the ECP5 and they are working on reverse engineering the
Xilinx 7 series bitstream as well.

http://www.clifford.at/icestorm/
https://www.crowdsupply.com/1bitsquared/icebreaker-fpga
https://www.crowdsupply.com/tinyfpga/tinyfpga-bx

There are some quirks but  worth checking out for anyone doing digital
audio or video who has been frustrated by the fpga vendor tools and cost of
entry. Very cheap open source dev boards available.


On Mon, Sep 30, 2019 at 3:24 AM Richie Burnett <rburnett at richieburnett.co.uk>
wrote:

> Out of interest does anyone know what FPGA novation use in their Peak and
> Summit synths?
>
> -Richie,
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
>
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From paula at synth.net  Mon Sep 30 21:56:51 2019
From: paula at synth.net (paula at synth.net)
Date: Mon, 30 Sep 2019 20:56:51 +0100
Subject: [sdiy] Novation Peak FPGA ?
In-Reply-To: <CANBp-JwzZeem3CeiXAPiBYbzws2p=NrdMAd3HTReQVFVRQzHqA@mail.gmail.com>
References: <A4148920A738451F8B6B1449270F42B0@RICHIEPC>
 <CANBp-JwzZeem3CeiXAPiBYbzws2p=NrdMAd3HTReQVFVRQzHqA@mail.gmail.com>
Message-ID: <46eea189db1d1c13a9d216edfbe919fa@synth.net>

There are a number of other FPGA synths out there (google is your
friend).
Perhaps the most impressive is the waldorf Kyra (i've had a play) which
sounds fabulous and is based on a ZynQ. 

I've been following the icebreaker-FPGA board, it's impressive. 

Paula

On 2019-09-30 20:41, Eric Schlappi wrote:

> I do not know what the Peak uses but I've been experimenting with an fpga based synthesizer using open source tools on the Lattice ICE40. Support is also available for the ECP5 and they are working on reverse engineering the Xilinx 7 series bitstream as well.  
> 
> http://www.clifford.at/icestorm/  
> https://www.crowdsupply.com/1bitsquared/icebreaker-fpga 
> https://www.crowdsupply.com/tinyfpga/tinyfpga-bx   
> 
> There are some quirks but  worth checking out for anyone doing digital audio or video who has been frustrated by the fpga vendor tools and cost of entry. Very cheap open source dev boards available. 
> 
> On Mon, Sep 30, 2019 at 3:24 AM Richie Burnett <rburnett at richieburnett.co.uk> wrote: 
> 
>> Out of interest does anyone know what FPGA novation use in their Peak and 
>> Summit synths?
>> 
>> -Richie, 
>> 
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at synth-diy.org
>> http://synth-diy.org/mailman/listinfo/synth-diy
> 
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
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