[Pd] Complex audio signals

[Chuckk Hubbard]

On 6/20/06, Piotr Majdak <piotr at majdak.com> wrote:
> > I was a little confused by the possibility
> > of having, for instance, 7 oscillators tuned within .001 Hz of each
> > other, since there is only one value for each channel, and I read that
> > FFT is more accurate if the frequency of the sound is known and is in
> > a harmonic relationship with the bins.
>
> If you want to FT a signal you describe and see the harmonics
> differences in the spectrum you need long block sizes. But not due to
> some FT limitations, it's just because you need longer signals in the
> time domain to represent several slightly detuned sines.

I didn't think of that.

> > Another question: if I just ran rfft~ on a signal, and then ran ifft~
> > on the transform, would that create the same signal as a complex
> > signal?
>
> Using [rfft~] you can process real signals only...

I meant like:
[readsf~] (for instance)
|
[rfft~]
|      |
[ifft~]  [num\ [num\
|   |     |         |
[czero~]
|
[dac~]

I suppose I could just try it and see if it works...

> > Too bad I go to an art school that would never pay for MathLab in a
> > million years.
>
> As Marc wrote you: try Octave...

Badass.

Thanks.
-Chuckk




>
> br, Piotr
>


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