[Pd] Complex audio signals

[Chuckk Hubbard]

On 6/24/06, Mathieu Bouchard <matju at artengine.ca> wrote:
> On Thu, 22 Jun 2006, Chuckk Hubbard wrote:
>
> >> you want to hear a difference, use [-~] to take the difference between the
> >> original signal and the one that's supposed to be identical. Then use [*~
> >> 1000000]. You might be able to hear some noises.
> > I tried that, couldn't hear it.
>
> try [*~ 10000000] then? zoom into the sound until you can hear the
> residue.
>
> > The reconstructed signal seems to sound fine, even with 4 detuned
> > oscillators far from block size, ignoring the actual values of the
> > FFT.
>
> This is because you play the reconstructed signal blocks exactly once
> each. I was talking about the effect of looping one block over and over,
> which is related to the fact that each block is treated as if it were
> periodic (unless using a window filter)

OK, that makes sense, but still, a real rfft~ into a complex ifft~
gives distortion even when each block plays once.  I read your reply
about the 90 deg phase, but I'm using waves that don't match the block
size.  The real output signal almost follows the input, and the
imaginary output appears to approach infinity at the ends...
Maybe a huge block size.