[sdiy] Generating acyclic waveforms?

[cheater cheater]

Hi Dave,

On Tue, Mar 23, 2010 at 07:29, Dave Manley <dlmanley at sonic.net> wrote:
> Ian Fritz wrote:
>>
>> [...] if you add together
>>
>> Sin ((w+eps)t) + Sin (2wt)
>>
>> You do not get a steady repeating waveform.
>

> isn't the whole point of the OP to not
> generate a steady repeating waveform, at least not on a cycle-to-cycle
> basis?  I assume the reason to try to create an acyclic waveform is to
> remove the sterile nature of a integer related harmonic structure, and
> produce a sound with, hopefully, interesting timbre and "movement".

That's very well said.

> It's not apparent to me how this can be done except through additive
> synthesis.

> Jittering the reset time of a vco (or more simply adding
> modulation via a CV) on a per-cycle basis alters the period of the
> fundamental not the relationship of the partials, so that isn't a viable
> approach.

There will be no constant-period fundamental. It will be randomly
modulated in time.

> I'm probably missing the big picture here because I haven't been paying
> attention since these long-winded discussions often devolve into a lesson in
> logic and pointless point-counterpoint style argument, or perhaps the thread
> has veered off topic as they are want to do, or perhaps I'm on a waffle
> rotating around your pancake, but

I hope the conversation doesn't devolve to this. Magnus has made some
interesting points about how things can be achieved. Let's concentrate
more on how anharmonic and acyclic generators can be constructed.
Explanation of stretched tuning is *not* on topic; the term can be
looked up on wikipedia. The question of whether some specific
instruments have stretched tuning is *not* on topic; the original
question of whether it does happen at all served its purpose for
justifying the approach and that's where it should stop. A quick
lowdown of what additive synths can do this is on topic, but an
in-depth listing of what can and what can't do stretched tuning is not
on topic, especially because stretched tuning is nowadays trivial with
sinewave additive approaches.

I'm hoping to see more discussion of generating waveforms that are
acyclic but not necessarily stretched-harmonic. A stretched-harmonic
waveform is nice, but that's just one way of getting the 'movement' in
your tone; maybe other kinds of acyclicity, not related to
stretched-harmonic waveforms, can be much easier to realize in analog.
I think jittering the reset of an VCO is one way, but it doesn't go
far enough; the waveform and the sound are still quite similar to the
ideal cyclic waveform. It would be ideal if one could look at the
scope and every cycle would look different, while the sound would be a
coherent pitch.

What kinds of acyclic waveforms are there, other than stretched
harmonic, pure noise, and jittered waveforms?

What about that stuff with resonators of multiple degrees of freedom, anyways?

Thanks
D.