MOTM

Paul,

Sounds very interesting.  I would like to such an oscillator with something better
than EPROM for waveform storage.  Something stable that survives power loss, perhaps
FLASH?  Maybe EEPROM would be better but I'd like an easier way to change around the
waveforms than to yank a chip and put it in a programmer...  Of course, depending on
the size of the memory and the quality and number of waveforms in it, I might not
want to reprogram it ;)

Regarding the controls, you know the drill, the more VC control the better!

Eric

--- Paul Schreiber <synth1@...> wrote:
> It just occured to me (well, actually yesterday talking with MOTM user in
> UK) that the 4,000
> CEM3340s I have sitting here collecting dust could be quickly converted to a
> newer version of
> the Digisound VCDO.
> 
> This uses the CEM3340 VCO chip in "ultrasonic" mode (ie say 1Khz to 100Khz
> range) to scan
> out waveforms in an EPROM. It's pretty easy to have VC'd waveform selection,
> etc etc a la the
> Wiard 'Waveform City' (which uses a technique prone to jitter errors).
> 
> Also cute is Windoze applett to 'draw' waveforms and then create Intel hex
> file to blow into EPROM
> if you have access to a programmer (like the $129 Needhams one).
> 
> Anyway, just a thought. Comments?
> 
> We could get Old Crow to add a PIC to do VC'd morphing (just an ADD then a
> SHIFT before DAC).
> Or digital GAIN control (0 to +5 goes into ADC on the PIC, with a MULT to
> gain scale. If you don't
> plug a signal in, there is a 100K pullup to +5 rail into ADC to get
> full-scale output).
> 
> Paul S.
> 
> 
> 
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In a message dated 00-07-16 21:34:08 EDT, you write:

<< Anyway, just a thought. Comments? >>


paul,
an excellent idea.........when can we expect to see one offered.? am not 
familiar with the didgisound modules but, in terms of function, seems a bit 
more like a modcan vco / wavetable osc.. i think the wiard has a much higher 
functional density.
best,
dave v.

Before all you guys say yeah, definately do it, did you read Paul's first 
paragraph?  Perhaps VCDO quantities won't be so large as to really affect 
3340 much, but those out of production chips are needed to repair a bunch of 
existing analogs (plus are used in Doepfer hi-end VCO), and maybe someday the 
very Synthtech VCDO will someday remain unrepairable do to lack of 3340s.  
Seems like there are other ways to do it.

If it were used, I'd like to see the module also usable as a regular (VCO) 
analog waveform source too.

However, I still don't fully understand the desire of those who want 
wavetable oscillators.  They give your nice sounding analog synth an annoying 
sterile digital sound that chipmunks when the pitch changes.  Also 
samplers/wave editors are so much more flexible in that department anyway, 
and can be played through an MOTM system.  Just my thoughts from someone who 
doesn't want any more delays of modules like the Low-End VCO, Mixer, 
Multiples, Phaseshifter, VCADSR, Panner/Crossfader(<-please) !

-Elhardt

From: <elhardt@...>
 Just my thoughts from someone who
doesn't want any more delays of modules like
the Low-End VCO, Mixer, Multiples, Phaseshifter,
VCADSR, Panner/Crossfader(<-please) !
-------
Since Elhardt and I disagreed on module construction speed, I will speak up
and agree with him here.  I would love to see the micro-VCO, accurate DC
mixer, phaseshifter and panner/crossfader as opposed to wavetable stuff.
Stooge Larry

>However, I still don't fully understand the desire of those who want 
>wavetable oscillators.  They give your nice sounding analog synth an annoying 
>sterile digital sound that chipmunks when the pitch changes.  Also 
>samplers/wave editors are so much more flexible in that department anyway, 
>and can be played through an MOTM system.

Anyone who says this has never played a SCI Prophet VS.  Of course
comparing a single VCDO to four 8x DCOs isn't really an accurate
comparison.  Ideally a MOTM VCDO wouldn't be just a wavetable
oscillator.  It'd be much cooler if it could also run in the subsonic
range and function as a LFO.  Add a four digit display, encoder,
and a trigger input so it can also act as a programmable multistage
looping envelope.  Now that would be cool.

-Cary

Heck Cary.  I don't know enough about this stuff to even dream that big.
Wow!! How would you use that looping envelope?
Simple minded, Stooge Larry

----- Original Message -----
From: Cary Roberts <cary.roberts@...>
Anyone who says this has never played a SCI Prophet VS.  Of course
comparing a single VCDO to four 8x DCOs isn't really an accurate
comparison.  Ideally a MOTM VCDO wouldn't be just a wavetable
oscillator.  It'd be much cooler if it could also run in the subsonic
range and function as a LFO.  Add a four digit display, encoder,
and a trigger input so it can also act as a programmable multistage
looping envelope.  Now that would be cool.

I never said I would do a VCDO *before* these. I'm just thinking about
what's shipping
next year.

Paul S.

----- Original Message -----
From: "J. Larry Hendry" <jlarryh@...>
To: <motm@egroups.com>
Sent: Sunday, July 16, 2000 11:26 PM
Subject: Re: [motm] VCDO?


> From: <elhardt@...>
>  Just my thoughts from someone who
> doesn't want any more delays of modules like
> the Low-End VCO, Mixer, Multiples, Phaseshifter,
> VCADSR, Panner/Crossfader(<-please) !
> -------
> Since Elhardt and I disagreed on module construction speed, I will speak
up

> and agree with him here.  I would love to see the micro-VCO, accurate DC
> mixer, phaseshifter and panner/crossfader as opposed to wavetable stuff.
> Stooge Larry
>
>
>
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Wow Cary, that's scary! (Hey , that rhymed) 

It sounds very similar to something I'm working on now...

Tony

> -----Original Message-----
> From: Cary Roberts [mailto:cary.roberts@...]
> Sent: Sunday, July 16, 2000 9:51 PM
> To: motm
> Subject: Re: [motm] VCDO?
> 
> 
> >However, I still don't fully understand the desire of those who want 
> >wavetable oscillators.  They give your nice sounding analog 
> synth an annoying 
> >sterile digital sound that chipmunks when the pitch changes.  Also 
> >samplers/wave editors are so much more flexible in that 
> department anyway, 
> >and can be played through an MOTM system.
> 
> Anyone who says this has never played a SCI Prophet VS.  Of course
> comparing a single VCDO to four 8x DCOs isn't really an accurate
> comparison.  Ideally a MOTM VCDO wouldn't be just a wavetable
> oscillator.  It'd be much cooler if it could also run in the subsonic
> range and function as a LFO.  Add a four digit display, encoder,
> and a trigger input so it can also act as a programmable multistage
> looping envelope.  Now that would be cool.
> 
> -Cary
> 
> 
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>

synth1@... writes:

>>I never said I would do a VCDO *before* these. I'm just thinking about 
what's shipping next year.<<

True, but past experience has gotten me a little concerned.  Like expensive 
Vocoders appearing from nowhere, preamps and lag processors being moved to 
the front of the line before more needed modules.  Even a sudden phaseshifter 
(which I like but) being wired up, yet still nothing on the more ancient 
mixer or vcadsr.  So I just wanted to make that point in my first VCDO 
response.

-Elhardt

>Heck Cary.  I don't know enough about this stuff to even dream that big.
>Wow!! How would you use that looping envelope?
>Simple minded, Stooge Larry

It pays to have synths with looping envelopes, ala Prophet VS.
A looping envelope is just like a regular multistage envelope
except that the looping point/stages are definable.  For example:

T1: 50  L1: 50
T2: 10  L2: 100
T3: 50  L3: 25
T4: 25  L4: 50

Repeat:  1 -> 3

For a looping envelope we introduce the key "repeat" parameter.
This defines which stages will repeat.  This could be set to
1 -> 2, 2 -> 3, 3 -> 4, 1 -> 3, 2 -> 4, 1 -> 3, etc, etc.  
So what happens in the above scenario is that we get a medium
attack to 50% level, then a speedy jump to 100%, then a medium
decay to 25%, then a jump to 50% in the fourth stage.  Since we
defined repeat as 1 -> 3, nothing happens in the first stage since
stage 1 is also set at 50%.  But then we get a quick jump to 100%
then decay to 25% then back to stage 1 over and over again.

Attached is a rough approximation of what the CV output would
be when a gate/trigger is received.

-Cary

My initial reaction is YES YES YES!  I'd LOVE to play with a waveform
oscillator.  I don't understand exactly what VC'd morphing means, but it
sounds interesting.  FM control is necessary, of course.

My only concern is, as Elhardt pointed out, the lifespan of these chips.
Four thousand seems like a lot, but eventually I suppose that supply will
run out.  How often do these chips burn out?  Do we need to take any extra
precautions using them?  Perhaps a backup chip would be a good idea?  I know
I sound paranoid, but...

--PBr

> -----Original Message-----
> From:	Paul Schreiber [SMTP:synth1@...]
> Sent:	Sunday, July 16, 2000 6:38 PM
> To:	MOTM listserv
> Subject:	[motm] VCDO?
> 
> It just occured to me (well, actually yesterday talking with MOTM user in
> UK) that the 4,000
> CEM3340s I have sitting here collecting dust could be quickly converted to
> a
> newer version of
> the Digisound VCDO.
> 
> This uses the CEM3340 VCO chip in "ultrasonic" mode (ie say 1Khz to 100Khz
> range) to scan
> out waveforms in an EPROM. It's pretty easy to have VC'd waveform
> selection,
> etc etc a la the
> Wiard 'Waveform City' (which uses a technique prone to jitter errors).
> 
> Also cute is Windoze applett to 'draw' waveforms and then create Intel hex
> file to blow into EPROM
> if you have access to a programmer (like the $129 Needhams one).
> 
> Anyway, just a thought. Comments?
> 
> We could get Old Crow to add a PIC to do VC'd morphing (just an ADD then a
> SHIFT before DAC).
> Or digital GAIN control (0 to +5 goes into ADC on the PIC, with a MULT to
> gain scale. If you don't
> plug a signal in, there is a 100K pullup to +5 rail into ADC to get
> full-scale output).
>

FWIW, Paul's previously stated policy has been to set aside one chip for
every installed chip for the out-of-production ones. So you're covered for
at least one mishap ;)

I'd rather see a design using currently available (and hopefully available
long into the future) components, myself.

David.

> -----Original Message-----
> From: Brousseau, Paul E (Paul) [mailto:noise@...]
> Sent: Monday, July 17, 2000 9:44 AM
> To: 'motm@egroups.com'
> Subject: RE: [motm] VCDO?
>
>
> My initial reaction is YES YES YES!  I'd LOVE to play with a waveform
> oscillator.  I don't understand exactly what VC'd morphing means, but it
> sounds interesting.  FM control is necessary, of course.
>
> My only concern is, as Elhardt pointed out, the lifespan of these chips.
> Four thousand seems like a lot, but eventually I suppose that supply will
> run out.  How often do these chips burn out?  Do we need to take any extra
> precautions using them?  Perhaps a backup chip would be a good
> idea?  I know
> I sound paranoid, but...
>
> --PBr
>
>
> > -----Original Message-----
> > From:	Paul Schreiber [SMTP:synth1@...]
> > Sent:	Sunday, July 16, 2000 6:38 PM
> > To:	MOTM listserv
> > Subject:	[motm] VCDO?
> >
> > It just occured to me (well, actually yesterday talking with
> MOTM user in
> > UK) that the 4,000
> > CEM3340s I have sitting here collecting dust could be quickly
> converted to
> > a
> > newer version of
> > the Digisound VCDO.
> >
> > This uses the CEM3340 VCO chip in "ultrasonic" mode (ie say
> 1Khz to 100Khz
> > range) to scan
> > out waveforms in an EPROM. It's pretty easy to have VC'd waveform
> > selection,
> > etc etc a la the
> > Wiard 'Waveform City' (which uses a technique prone to jitter errors).
> >
> > Also cute is Windoze applett to 'draw' waveforms and then
> create Intel hex
> > file to blow into EPROM
> > if you have access to a programmer (like the $129 Needhams one).
> >
> > Anyway, just a thought. Comments?
> >
> > We could get Old Crow to add a PIC to do VC'd morphing (just an
> ADD then a
> > SHIFT before DAC).
> > Or digital GAIN control (0 to +5 goes into ADC on the PIC, with
> a MULT to
> > gain scale. If you don't
> > plug a signal in, there is a 100K pullup to +5 rail into ADC to get
> > full-scale output).
> >
>
> ------------------------------------------------------------------------
> Want to be the first to know?
> Be the first to see sneak peeks of new music, movies and games!
> http://click.egroups.com/1/6693/6/_/529958/_/963848574/
> ------------------------------------------------------------------------
>
>

Elhardt writes:
>However, I still don't fully understand the desire of those who want
>wavetable oscillators.  They give your nice sounding analog synth an annoying
>sterile digital sound that chipmunks when the pitch changes.  Also
>samplers/wave editors are so much more flexible in that department anyway,
>and can be played through an MOTM system.

I guess the reason I'm interested is because I'm not sure how it would
sound, and the best way to find out is to use one! This is much the same
reason I got my first Dark Star, no one could adequately explain what it
did, so I had to build one just to find out.

Has anyone else noticed that Wiard is offering the waveshaping part of the
waveform city as a kit? It also requires an EEPRROM for the wavtables. I
think I may be orderring one, they're supposed to be available in a few
weeks.

____________________________________________
Dave Trenkel : improv@...
Minus Web Site: http://listen.to/minusmusic
Minus MP3's: http://www.mp3.com/-minus-
____________________________________________

Hi All !

Good idea, but some extra features would be nice :  once one has a 
pic (or other avr :) ) on board, it should'nt be too difficult to 
have a "sound load" mode, where the pic is connected to a pc by 
serial i/f, and the pic is used to fill a battery backed ram or to 
program a flash-eprom .

A sideways look at how a ppg or microwave does tricks might be 
beneficial .

A Prophet VS does not sound sterile ;^)  Maybe it has to do with that 
strange way the pitches are derived from a hf clock .  Can't remember 
exactly how it works, but it introduces phase jitter (so that might 
not be all bad :) ) .  This was mentioned on either AH or synth diy 
maybe 5 months ago .  The exact recipe was not given tho .

Maybe a silly idea, but using an up-down counter for addressing and 
adding a zero crossing detector (and positive only "folder") to a 
linear fm input could give a thru zero fm osc ... with selectable 
waveforms .  (Juergen ?)  Anyone got the TX81 waves handy ?  ;-) 

And sync, many kinds ... %~)

Bye for now .


Keep 'em oscillating :)


Hugo
=