MOTM

Eek!  I need a bit of a break from the uModule discussion.

I've got two questions...  

THE FIRST QUESTION

First off is a technical question that'll sound newbie-ish.  That's 
ok, since I could easily be considered a newbie.  All of my analog 
synths are single VCO based, so I have *zero* experience with hard 
sync.  My understanding is that it's a way of retriggering the wave 
(say sawtooth) even though it may have gone through more or less than 
one oscillation, so you'll get a one-and-a-half cycle wave every 
cycle, or a less-than-one cycle wave every cycle.  Assuming I'm 
right, here's the question:

How do you wire it?

Say I have a 310 uVCO and a 300, can I run the output of the 310 into 
the "hard sync" jack on the 300?  If so, the CV going into the 310 
controls the pitch, whereas the CV going into the 300 only controls 
the timbre of the sound?  (they could both track the main CV i'm 
playing with the coarse adjustment on the 300 set to give me a 
specific sound)

If that's how it works, then great, my understanding is mostly right, 
and I've got lots of interesting hard-sync modulation ideas that I'm 
sure everyone else has been doing since the mid 70s.  <grin>

THE SECOND QUESTION

(pre-addendum [written afterwords, placed in front of]  This is all 
LPF stuff)

I'm looking for a certain aspect to a filter... a certain sound.  Say 
I have a patch that has a very very slow attack and decay, taking 
maybe 10 seconds to creep up and 10 seconds to creep back down.  
That's controlling not just the VCA, but the cutoff on the VCF.  The 
VCF is set to a very high Q, near (or possibly at) self oscillation.  
The sound I'm looking for (and I'm pretty sure I've heard it) is this:

The resonant sound, naer sine wave, of the filter *tracking* the 
harmonic content of the source wave.  So, say if this patch were set 
with no oscillator, and the filter self oscillating, you'd here a 
continuous pitch shift.  That's not what I want.  With the oscillator 
going, I'm looking for that resonant peak to follow the content of 
the wave... so what you hear as the filter's cutoff increases, is the 
resonant sound "jumping" from one frequency to another.  I don't know 
if this is a Roland sound or a moog filter sound or what (maybe it's 
a result of overdriving a filter), but the synth I have uses some CEM 
filter chip or another, and it doesn't seem to do what I want.

Am I just crazy, or does this sound exist? If it does, can I get a 
filter that behaves this way in an MOTM setup?  Will the 440 do it?  
So far, judging from the descriptions and demos, it seems the closest 
one.

I'm pretty sure I'm not crazy about this stepped-plateau effect, I'm 
pretty sure I've heard it in a bunch of slow pad sounds.  Anyway, any 
hints would be great, I *really* need a filter that'll behave this 
way.

Sorry for the UberSpam Longish post, but since I want an MOTM filter 
to do this, this seems like the right place to go.

-Geoff

>
> How do you wire it?
>
> Say I have a 310 uVCO and a 300, can I run the output of the 310 into
> the "hard sync" jack on the 300?  If so, the CV going into the 310
> controls the pitch, whereas the CV going into the 300 only controls
> the timbre of the sound?  (they could both track the main CV i'm
> playing with the coarse adjustment on the 300 set to give me a
> specific sound)

Correct, and use the SHAPE of the '310 on PULSE.

The "pitch" and "timbre" depends on which VCO is faster (higher frequency). That is the dominant
VCO.


> The resonant sound, naer sine wave, of the filter *tracking* the
> harmonic content of the source wave.  So, say if this patch were set
> with no oscillator, and the filter self oscillating, you'd here a
> continuous pitch shift.  That's not what I want.  With the oscillator
> going, I'm looking for that resonant peak to follow the content of
> the wave...

You want a '440. The key here is to have the CV of the VCO being dominant in the VCF as well, and
carefully adjusting the VCF FREQ and FM to cause the VCF to "track" the VCO. Also, this effect
will be more audible for saw and Pulse waveforms. You need to set the ADSR into the VCF to be in
the Sustain portion when you want to hear the effect, and the 'tracking' will be the Sustain
voltage attenuated by the FM pot.

Paul S.

I think I misdescribed what I was going for, but maybe not... in this 
hypotehtical patch i made, the VCO was maintaining the same 
frequency... it was just that the resonant peak of the filter wasn't 
sliding up in frequency smoothly, it sounded like it was jumping from 
harmonic to harmonic (of the source tone)  Since there was just one 
note being sustained for 20 seconds, it doesn't seem like I'd need to 
patch into any frequency control on the VCF, though if I wanted to be 
able to play this sound...
arrgh getting incoherent here.  I think you probably *did* understand 
my question, and are just advising me on how to get the VCF to track 
the pitch of the VCO, which I can do (usually)

Anyway the sound I'm going for is a single pitched VCO with a VCF, 
and the sinewave type sound, the resonant sound that VCFs make at 
high resonance... the filter was being swept smoothly by the 
enveloper, but the resonant peak sound hopped.  I might just try to 
dig up a clip of it on my machine.  If I can manage to find something 
with that sound, I'll stick it on my site and post the URL.

Thanks for the help, though!

--- In motm@y..., "Paul Schreiber" <synth1@a...> wrote:
> >
> 
> You want a '440. The key here is to have the CV of the VCO being 
dominant in the VCF as well, and
> carefully adjusting the VCF FREQ and FM to cause the VCF to "track" 
the VCO. Also, this effect
> will be more audible for saw and Pulse waveforms. You need to set 
the ADSR into the VCF to be in
> the Sustain portion when you want to hear the effect, and 
the 'tracking' will be the Sustain

> voltage attenuated by the FM pot.
> 
> Paul S.

>>>>
Say I have a 310 uVCO and a 300, can I run the output of the 310 into 
the "hard sync" jack on the 300? If so, the CV going into the 310 
controls the pitch, whereas the CV going into the 300 only controls 
the timbre of the sound? (they could both track the main CV i'm 
playing with the coarse adjustment on the 300 set to give me a 
specific sound)
<<<<

You have the right idea. To do the classic 'hard sync' sounds, be 
sure and run the 300 at higher frequencies than the 310 (using your 
patch example). Use a pulse wave output from the 310 to connect to 
the 300's sync input.

>>>>
The resonant sound, naer sine wave, of the filter *tracking* the 
harmonic content of the source wave. So, say if this patch were set 
with no oscillator, and the filter self oscillating, you'd here a 
continuous pitch shift. That's not what I want. With the oscillator 
going, I'm looking for that resonant peak to follow the content of 
the wave... so what you hear as the filter's cutoff increases, is the 
resonant sound "jumping" from one frequency to another. 
<<<<

I just patched up both a MOTM-420 and a MOTM-440 to check this, and 
was able to get the 'jumping harmonic series' effect with either one. 
The 440 sounds more pure, the 420 more buzzy. The secret is adjusting 
the resonance to just BELOW hard oscillation. Also remember that 
there is a certain range (starting from the fundamental VCO frequency 
and moving upward through the first 10 harmonics or so) that the 
harmonics of the VCO are far enough apart so that this effect is 
pronounced. As you sweep further and further up into the high 
harmonics, they become so close together in frequency that the effect 
disappears, and it sounds continuous instead of stepped.

Moe

My limited experience says your basic understanding is OK.  I love hard sync
type sounds.  In fact, some of my first MOTM samples on Paul's website were
made with two VCOs using hard sync to get what Paul calls the screaming
gee-tar sounds way back before the first MOTM filter. :)

When I do it, both VCOs get their CV from the same source, so everything
tracks.  But, you could do it differently if you wanted the timbre to change
across the frequency range.  But, the frequency of VCO # 1 that is providing
the signal for hard sync actually controls the frequency of both VCOs.  The
frequency setting on VCO # 2 only determines how much wave you travel
through before VCO #1 cause VCO # 2 to reset. (That's my simple way of
looking at it).  VCO # 2 frequency adjustment needs to be lower than VCO # 1
so that VCO # 1 is forcing VCO faster as you cannot force it slower.

Larry Hendry (experience level above zero, but just barely) <snicker>

P.S.  I like to use a EG to modulate the frequency of the VCO under sync.
That way the EG can be dialed in to give the sync sound an almost filter
like effect with each new gate.

----- Original Message -----
From: sucrosemusic <sucrosemusic@...>
First off is a technical question that'll sound newbie-ish.  That's
ok, since I could easily be considered a newbie.  All of my analog
synths are single VCO based, so I have *zero* experience with hard
sync.  My understanding is that it's a way of retriggering the wave
(say sawtooth) even though it may have gone through more or less than
one oscillation, so you'll get a one-and-a-half cycle wave every
cycle, or a less-than-one cycle wave every cycle.  Assuming I'm
right, here's the question:

How do you wire it?

Say I have a 310 uVCO and a 300, can I run the output of the 310 into
the "hard sync" jack on the 300?  If so, the CV going into the 310
controls the pitch, whereas the CV going into the 300 only controls
the timbre of the sound?  (they could both track the main CV i'm
playing with the coarse adjustment on the 300 set to give me a
specific sound)

If that's how it works, then great, my understanding is mostly right,
and I've got lots of interesting hard-sync modulation ideas that I'm
sure everyone else has been doing since the mid 70s.  <grin>

> the wave... so what you hear as the filter's cutoff increases, is the
> resonant sound "jumping" from one frequency to another.  I don't know

If I understand correctly, you want a S&H between the EG and the Freq
Cutoff. EG OUT goes into the S&H IN, S&H OUT goes into filter FM1. S&H SPEED
controls the rate of the jumping; FM1 controls the depth of the effect.

At least, that's how it works in my head...

At 5:44 AM +0000 12/06/01, sucrosemusic wrote:
>
>I think I misdescribed what I was going for, but maybe not... in this
>hypotehtical patch i made, the VCO was maintaining the same
>frequency... it was just that the resonant peak of the filter wasn't
>sliding up in frequency smoothly, it sounded like it was jumping from
>harmonic to harmonic (of the source tone)
>
>Anyway the sound I'm going for is a single pitched VCO with a VCF,
>and the sinewave type sound, the resonant sound that VCFs make at
>high resonance... the filter was being swept smoothly by the
>enveloper, but the resonant peak sound hopped.

Are looking for that sound when Neo drops into the Matrix??  Anyway, that
sound can be played with a mod wheel.  You assign the mod wheel to the VCF,
crank the resonance to where it just about self-oscillates, hold down one
note, and slowly pull back the wheel pausing as each harmonic rings.