Originally Posted by forest_wyvern

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.

Originally Posted by normanion

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!

Originally Posted by normanion

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.

Originally Posted by xanderbeanz

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.

Originally Posted by Gearlust

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.

Originally Posted by TheOmegaShadow

I saw my MODX has the wavefolder effect in it, I'll have a play with it and see how it sounds...

Originally Posted by xanderbeanz

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.

Originally Posted by normanion

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...

Originally Posted by xanderbeanz

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.

Originally Posted by normanion

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. :]