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Synths with Wavefolders in them
Old 25th November 2020 | Show parent
  #31
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xanderbeanz's Avatar
 
🎧 5 years
Quote:
Originally Posted by forest_wyvern View Post
Technically they are the same. A wavefolder is a waveshaper with an infinite (periodic) characteristic, like triangle or sine wave.

The difference is parameter ranges. With a shaper, it will be applied to an audio signal with only limited internal gain ('drive').

A folder usually operates under very large gains that are first applied to the input. These gains activate the 'periodic' region. For instance, put in a triangle wave with an amplitude of N (odd), the wavefolder outputs a triangle wave of amplitude 1 at N times the frequency. So to get 31st 'harmonic' (a perfectly usable result), you apply a gain of 31 internally.

On the other hand, where you'd want to use a moderate gain is when the input's a sample or complex audio signal, not a pure waveform. Here the 'shaper' can be more useful. The 'folder' will simply produce white noise or some other distorted mess on its way to white noise.

So 'folder' vs. shaper distinction refers more to operating range, and preferred choice of input signals, not the underlying mathematics which is actually the same.
Thanks for putting this better than I could have done. Yes, I’ve always seen it that a shaper is a train stop on the way to fold town
Old 25th November 2020 | Show parent
  #32
Lives for gear
 
The Nord Wave does some great sounding Wave folding-shaping on all Wave forms.

(Puns shamelessly intended, and I have no idea what the algorhythms are really doing under the hood, but the fact remains that it sounds awesome)
Old 25th November 2020 | Show parent
  #33
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xanderbeanz's Avatar
 
🎧 5 years
Quote:
Originally Posted by normanion View Post
Hi,

I just looked into your equation and have no time to finish it, but at first glance I can see it is not frequency modulation, but phase modulation. When doing phase modulation it should look something like this:

A(t) = Wc[2piFc*IWm(2piFmT)*T + phase]

Do yourself simple mind experiment and substitute Wm with slow sine function and you can see, that in FM it will be swinging from higher pitch to lower, while with phase modulation at sin(pi/2) pitch will be at Fc.

Or am I too tired to understand something here? But I was generally good at math and dealt with a lot more complex functions... :/

Another thing is that some people are pasting pictures of some resonant distorted wave saturation, while wavefolding is mirror image of part of wave that would go above threshold folded below that threshold.

Cheers!
I’ll have to chat to the book’s author about this. This book did discuss how to perform waveshaping in a phase modulation-type architecture, so I assumed, at first glance, that he was smarter than me and I was missing something.
Old 25th November 2020 | Show parent
  #34
Gear Maniac
 
Quote:
Originally Posted by normanion View Post
Another thing is that some people are pasting pictures of some resonant distorted wave saturation, while wavefolding is mirror image of part of wave that would go above threshold folded below that threshold.
Yo, sorry for spamming pic that was a little off, I wanted to make my question about wavefolding vs waveshaping more visual but more or less answered it myself The links would be enough.
Old 25th November 2020 | Show parent
  #35
Gear Maniac
Quote:
Originally Posted by xanderbeanz View Post
I’ll have to chat to the book’s author about this. This book did discuss how to perform waveshaping in a phase modulation-type architecture, so I assumed, at first glance, that he was smarter than me and I was missing something.
Do that, but also let me make some correction, because I was too tired to see that I let my equation be multiplied by zero. And please be sure to come back with results - whatever author said. I'm happy to be corrected and learn new stuff.

I will come back with proper solution, when I restore my energy, which might be in few days.

Cheers!
Old 25th November 2020 | Show parent
  #36
Gear Maniac
Quote:
Originally Posted by Gearlust View Post
Yo, sorry for spamming pic that was a little off, I wanted to make my question about wavefolding vs waveshaping more visual but more or less answered it myself The links would be enough.
No worries. It's good to chat and learn.

P.S. Xanderbeanz, I would go more with something like this:
A(t) = Wc[2pi(Fc+IWm(2piFmT))*T + phase]
or
A(t) = Wc[2piFc*(1+IWm(2piFmT))*T + phase]
but this might need correction, because signal needs to be continuous or I am too paranoid and am overthinking it... again...
Old 25th November 2020 | Show parent
  #37
Lives for gear
 
I had a little play with this this evening. just one element Tri wave into the wave folder and then multi FX on insert B. Yeah good fun. A reasonable number of parameters to make interesting sounds.

Have you tried it out yet?

Quote:
Originally Posted by TheOmegaShadow View Post
I saw my MODX has the wavefolder effect in it, I'll have a play with it and see how it sounds...
Old 26th November 2020 | Show parent
  #38
Gear Maniac
Quote:
Originally Posted by xanderbeanz View Post
I’ll have to chat to the book’s author about this. This book did discuss how to perform waveshaping in a phase modulation-type architecture, so I assumed, at first glance, that he was smarter than me and I was missing something.
F**k me! While I know, that yours is recipe for phase modulation, as f(x-a) is moving function f(x) by a, I also know, that my first two suspects are incorrect. Now I am tired as hell and also unable to sleep without trying to solve that. Anyway: here is my little thought experiment.

Synths with Wavefolders in them-img_3411.jpg
(I cut my formulation of Dirichlet conditions)

One cannot simply add modulator to frequency. One problem is, that taking formula as it is, would simply cut final wave because at point of change, because sine with double frequency would be at 0 point going down. It should be moved to match cycle amount passed. I could simply add that with phase modulation ;]
But I am worried that I might end up without general solution. The only thing that comes to mind, to be sure, is to use derivatives, calculating df(x)/dx at point x as a function of f(x). So to speak. Need to formulate it. Right now I try to let it go, simultaneously being excited by problem that is to solve...
Attached Thumbnails
Synths with Wavefolders in them-img_3411.jpg  
Old 26th November 2020 | Show parent
  #39
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xanderbeanz's Avatar
 
🎧 5 years
Quote:
Originally Posted by normanion View Post
F**k me! While I know, that yours is recipe for phase modulation, as f(x-a) is moving function f(x) by a, I also know, that my first two suspects are incorrect. Now I am tired as hell and also unable to sleep without trying to solve that. Anyway: here is my little thought experiment.


(I cut my formulation of Dirichlet conditions)

One cannot simply add modulator to frequency. One problem is, that taking formula as it is, would simply cut final wave because at point of change, because sine with double frequency would be at 0 point going down. It should be moved to match cycle amount passed. I could simply add that with phase modulation ;]
But I am worried that I might end up without general solution. The only thing that comes to mind, to be sure, is to use derivatives, calculating df(x)/dx at point x as a function of f(x). So to speak. Need to formulate it. Right now I try to let it go, simultaneously being excited by problem that is to solve...
There’s one bit I’m really not understanding. If you are doing f(x-a), do you not also need to be doing f(x+a)? I’m talking in a linear sense here...just to be able to make sure that the modulation is stable across a wide range out outcomes.
Old 26th November 2020 | Show parent
  #40
Gear Maniac
Quote:
Originally Posted by xanderbeanz View Post
There’s one bit I’m really not understanding. If you are doing f(x-a), do you not also need to be doing f(x+a)? I’m talking in a linear sense here...just to be able to make sure that the modulation is stable across a wide range out outcomes.
It doesn't really matter, how you write it, because a belongs to real number. I just put it like that, because if you want to move f(x) right by an a, then you subtract an a from argument, hence: f(x-a). If you want to move function up by an a, then you add an a to function, hence: f(x) + a. I don't remember this rule, I always have it's shape and position in my head and then ask myself, what x should be, to move it into zero position (for some sort of symmetry regarding some axis) and for f(x-a), when I put x=a, i get f(0).

Or I didn't understand your question. Then please, explain, what you meant. :]
Old 26th November 2020 | Show parent
  #41
Gear Head
 
🎧 10 years
Have you tried putting the formula into Desmos? Really good way to visualise and get a feel for how they change.

I cleaned up one I was working on a while ago https://www.desmos.com/calculator/nw1fuiagdd. You can set the frequency to zero and see that Phase modulation gives sine based wavefolding.

There's FM too, but you have to turn it on because its slow. After a lot of messing around with strange results, I realised you had to accumulate the frequency changes. Which on desmos goes really slowly. Need to turn it on to show it by clicking on the circle on Row 19.

Also, the analysis of the actual Buchla circuit is really interesting to read. Looks like the folds are going to be more sharply defined and there are only a limited number of folds before it just saturates. So not the same as a sine waveshaper and much harder for a synth to calculate.
Old 26th November 2020 | Show parent
  #42
Gear Head
 
🎧 10 years
Bit more messing with Desmos. This, using harmonic series to get square and saw as phase modulators of a sine wave.
https://www.desmos.com/calculator/ww7l1qjdc4

Last edited by nick66; 26th November 2020 at 09:54 PM.. Reason: Better phase
Old 26th November 2020 | Show parent
  #43
Lives for gear
 
xanderbeanz's Avatar
 
🎧 5 years
Quote:
Originally Posted by normanion View Post
It doesn't really matter, how you write it, because a belongs to real number. I just put it like that, because if you want to move f(x) right by an a, then you subtract an a from argument, hence: f(x-a). If you want to move function up by an a, then you add an a to function, hence: f(x) + a. I don't remember this rule, I always have it's shape and position in my head and then ask myself, what x should be, to move it into zero position (for some sort of symmetry regarding some axis) and for f(x-a), when I put x=a, i get f(0).

Or I didn't understand your question. Then please, explain, what you meant. :]
No you answered it perfectly. It should be noted that were rubbing up against the very limits of my mathematical knowledge here, so I’m going to ask dumb questions
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