MOTM

Here would be some things I would like to see in an MOTM vocoder:

## Wide range, not limited to vocal range;

## However, certain niceties catered to vocal processing, such as the
standard sibilance bypass for consonants/plosives;

## Access points for the individual bands on both the spectrum encoder and
decoder sides - it's gotta be modular, right?;

## I wonder what variable slopes on the bands would sound like? Is 'tighter'
better for all applications?;

## The ability to cross-wire the 1-to-1 relationship between the bands on
the two halves. For instance, to flip the spectrum so that higher tones on
the decoding side affect lower tones on the encoding side. That way it
becomes a flexible, generic spectral cross-modulator, not just a simple
1-to-1 imposition of one spectrum on another.

If voltages can be tapped off the individual envelope follower outputs, then
these voltages could conceivably be encoded as MIDI continuous controller
messages and be recorded with an off-board V-to-MIDI encoder. Hmm, has that
ever been done before?

With access to the Encoder-side bands, the unit could be used as a big VCA
bank, perfect for modulating with a Shepard Function Generator, or perhaps
to play with a little pseudo-additive synthesis via a bank of EGs.

At the very least, access to the VCAs would allow flexible pre-biasing and
altering of the carrier/encoder side for interesting effects using the other
modules.

Perhaps the number of bands could be reduced while still keeping it detailed
by making the filter banks parametric? That way the bands can be positioned
in the spectrum depending on the use it's being put to (i.e., vocal range)
while reducing overall cost. I dunno, maybe that brings its own problems to
the table.

Ultimately, it would be nice if it worked stand-alone as a vocoder, but
still opened itself up fully to be useful as a component of the modular,
too. Maybe the vocoder proper is in a relatively Spartan package with a
"breakout panel" that can be added with a wire harness to give access to the
patch points, available separately.

 -----Original Message-----
From: 	Paul Schreiber [mailto:synth1@...] 
Sent:	Thursday, 16 March, 2000 8:33 AM
To:	MOTM listserv
Subject:	[motm] Vocoder plans?

From: "Paul Schreiber" <synth1@...>

JH & I are just "tire-kicking" the vocoder idea. We are NOT trying to
rip-off EMS! Rather, just
in the info-gathering stages.

The MOTM plan is NOT to be in the $600 range, but more like the $1400 range.
There is just
too much R&D and parts. it would be 90% assembled, like the MOTM-900 is.
Mostly SMT, due
to the vast number of parts (like 280 op amps!) It will need it's own
supply.

Also, there are many, *many* tradeoffs. The much-touted Sennheiser uses 40
bands (not very
sophisticated filterd, a 2-transistor BP) but is hand-tweaked! Also, it is
set for "best response"
for vocals, not necessarily a wide range.

And then it has 138 panel controls...........hmm......

But then again, only 60 were made at $18,000ea (the current price is
$5000-$7000).

Not really interested in a "small" PAiA/MAM 11-band for $600. Why? Ask
anybody that owns one.
They do "work", but if you are really into Kraftwerk-type quality, *AIN'T
GONNA HAPPEN* with
the low-end stuff.

If we DO decide, then we will ask for $500 deposits to get the R&D effort
off the ground.

<Paul S>



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Since the only vocorder I ever used was an old korg vocorder, what can been
done besides vocal processing? What makes a vocorder great. As always, if a
vocorder can be an asset in unique sound creation i'm all for it, but the
only use I've even known one for was the "robot voice" effect. Does a
vocorder need a vocal input to function? will it work with other instuments
/ sound sources? Any feedback would be helpful -Nate

[By the way, it's "Vocoder" for "Vocal Encoder / Decoder," not "Voco*r*der."
I hear a lot of people say it that way thinking that it's related to a
'recorder' but that's not the case.]

Think of vocal processing as one way to use a vocoder, not the only way
(although Homer Dudley did invent it for voice use, ostensibly as an
experiment in telephone communications, like so much of the equipment we
use).

A vocoder analyzes the frequency/amplitude spectrum of one signal and
'imposes' it on another. The human voice is very complex, and difficult to
synthesize (Tomita's little "voices" doing countdowns and such on his "The
Planets" album are about as good as you typically get without a vocoder).
The problem is controlling all of the subtle aspects of voice... generally
too much to do with two hands. A vocoder lets you simply speak into the
"modulator" input and impose that spectrum onto a "carrier." Some vocoders
have built-in vocal samples as carriers (like the Korg DVP-1, which I have),
but this is so limited-if you can't choose the sound that you want to
actually *shape*, what good is it?

A vocoder works by inputting a signal into the Analysis section (the
Modulator signal). It is then sliced into frequency bands--the more the
better for best resolution---via a fixed filter bank (think graphic
equalizer). Each slice of the frequency band is passed to an envelope
follower. So now we have a control voltage that tracks each slice of the
frequency spectrum.

You also have a Carrier input that feeds the Synthesis section. This goes to
an identical fixed filter bank, which slices up the frequency spectrum the
same way, but in this case the slices go to VCAs. The VCAs from this section
are controlled with the CV outputs of the EFs from the previous section. The
outputs of the VCAs are then mixed together to an output (but it would be
nice if you could tap them before they did that... hint-hint...). In this
way, the spectrum of the second signal "follows" that of the first.

Because the subtle non-vowel plosives of speech ("shh" and the pop from a
"p" and so on) don't 'analyze' well with vocoders, especially those with a
small number of frequency bands, most vocoders have a bypass chain that goes
through a highpass filter to allow these sibilant sounds to bleed into the
carrier output to increase intelligibility.

Wendy Carlos made a vocoder out of two Moog Fixed Filter Banks, ten EFs and
ten VCAs for use in Timesteps and the Beethoven's Ninth parts of the
Clockwork Orange soundtrack. There are photos of it in the booklet from her
new S-O-Bach boxed set.

Okay, theory behind us... does it need a vocal input? Absolutely not! Like I
say, that just shows off the device because changes to the voice are easily
recognized by the human brain, and because it's so hard to synthesize any
other way.

But there are loads of cool things you can do with a vocoder. Feeding
percussion into the Mod input is very neat---each drum, etc., in a drum set
"lights up" a different part of the spectrum, so if you impose this onto
another sound---even with voice as the *Carrier* this time!---you get wild
results. I've heard weird metallic drum kits created this way by drumming
into the modulator and as a carrier using a ring-modulated sound, where one
of the VCOs was also controlled by a separate EF tracking the modulator
input. Very expressive... sounded like a drum kit made up of car fenders,
gongs, etc.

I've always been interested in being able to screw around with the
relationships between the bands so that the voice could be used to
formant-filter another sound, but not in the 1-to-1 way that produces
recognizable vowel sounds on the other side. When I was in high school, some
friends and I had an idea of creating a weird band called the "Rigelian War
Monks" where each of us would sing into a similarly cross-wired vocoder to
create a 'foreign language' of these War Monk performers (who would be
anonymously hooded in black and red). Kind of a Residents from Space thing
before I'd ever heard of the Residents. We were young, and never got our
hands of vocoders that allowed us to do that.

Even simply being able to shift the control relationship between the two
halves would allow you to impose a formant from, say, a low male voice onto
the upper part of another spectrum for a female-ish voice. Having the bands
locked 1-to-1, as it is with 99% of vocoders, is very limiting, it seems to
me. It almost demands that your carrier & modulator signals occupy the same
portions of the frequency spectrum, which cancels out a whole boatload of
possibilities.

I've also heard instruments with very recognizable formants---oboes,
banjoes, etc.---used as modulators to warp synthesizer pads, string
sections, etc. to very unique effect.

Wendy Carlos, on "Secrets of Synthesis" (highly recommended album)
demonstrates a vocoder used with a Pitchtracker to create fairly realistic
voices that are not her own. Perfect for demanding ransom money over the
telephone.

Oh well, enough typing. Back to my siesta...

 -----Original Message-----
From: 	Nathan Hunsicker [mailto:nate@...] 
Sent:	Thursday, 16 March, 2000 11:00 AM
To:	motm@onelist.com
Subject:	Re: [motm] Vocoder Wish List / Daydreams

From: Nathan Hunsicker <nate@...>

Since the only vocorder I ever used was an old korg vocorder, what can been
done besides vocal processing? What makes a vocorder great. As always, if a
vocorder can be an asset in unique sound creation i'm all for it, but the
only use I've even known one for was the "robot voice" effect. Does a
vocorder need a vocal input to function? will it work with other instuments
/ sound sources? Any feedback would be helpful -Nate

> From: Tkacs, Ken <ken.tkacs@...>
> Here would be some things I would like to
> see in an MOTM vocoder:
> 
> ## Wide range, not limited to vocal range;
> 
> ## However, certain niceties catered to vocal
> processing, such as the standard sibilance 
> bypass for consonants/plosives;

SNIP... out a lot of other cool sounding stuff (some of which I did not
even understand)

> Ultimately, it would be nice if it worked stand-alone
> as a vocoder, but still opened itself up fully to be
> useful as a component of the modular, too.

I would like to echo in particular these comments Ken has made.

> From: "Paul Schreiber" <synth1@...>
> 
> JH & I are just "tire-kicking" the vocoder idea.

Kick harder <snicker>

> The MOTM plan is NOT to be in the $600 range, but
> more like the $1400 range.

It the MOTM vocoder = MOAV (the one everyone points at 3 or 5 years down
the road and says "yes, that's the one you want,"  then $1400 seems like an
OK range for me.
 
> Also, there are many, *many* tradeoffs.

If you are making MOAV, the there should not be.

> And then it has 138 panel controls...........hmm......

A nice SIZE for MOAV would be 5U high X 10U wide, so that case and rack
guys alike could integrate it into their system.  Although that sounds
large, would it be easy to make it that small?
 
> If we DO decide, then we will ask for $500 deposits
> to get the R&D effort off the ground.

Hand poised over order form on MOTM site where it says "$500 deposit for
MOAV."
Sign me up.

Larry (don't know squat about what makes a vocoder good) Hendry

>[By the way, it's "Vocoder" for "Vocal Encoder / Decoder," not "Voco*r*der."
>
>I hear a lot of people say it that way thinking that it's related to a
>
>'recorder' but that's not the case.]



Thank god someone pointed that out to me, I feel like such a fool. All my
life I have heard people refer to this piece of equipment as a "vocoRder"
never realizing there is no "R" in the word.



>Wendy Carlos made a vocoder out of two Moog Fixed Filter Banks, ten EFs and
>
>ten VCAs for use in Timesteps and the Beethoven's Ninth parts of the
>
>Clockwork Orange soundtrack. There are photos of it in the booklet from her
>
>new S-O-Bach boxed set.


If I recall correctly those weren't standard fixed filter banks, Bob Moog
had specially modified them ( a 914 & 907) along with the envelope
followeres and VCA's to work as a vocoder. Was is actually a true vocoder?
-Nate

Right---Moog provided breakout points on the production filter banks so that
she could get access to the individual bands.

Sure, it was a real vocoder. What she did modularly is exactly what's going
on inside a basic vocoder sold as a unit. Conceptually, it's a simple,
rather clever device, but there are a whole bunch of parts involved. When
you talk about making one out of individual modules like Carlos did...
sheesh, I can't imagine what she must have paid for that thing. A few grand,
easily, even without the mods. And it was only ten bands. On the other hand,
being modular, she could always use those modules for other things (although
looking at pictures, it seems the wire harness stayed there once it was
installed).

 -----Original Message-----
From: 	Nathan Hunsicker [mailto:nate@...] 
Sent:	Thursday, 16 March, 2000 2:49 PM
To:	motm@onelist.com
Subject:	RE: [motm] Vocoder Wish List / Daydreams



If I recall correctly those weren't standard fixed filter banks, Bob Moog
had specially modified them ( a 914 & 907) along with the envelope
followeres and VCA's to work as a vocoder. Was is actually a true vocoder?

Precisely!

Dave

> From: "Tkacs, Ken" <ken.tkacs@...>
 
> Maybe the vocoder proper is in a relatively Spartan package with a
> "breakout panel" that can be added with a wire harness to give 
> access to the
> patch points, available separately.
>