[LAD] Paul's Extreme Sound Stretch

Robin Gareus robin at gareus.org
Fri Oct 1 01:01:45 UTC 2010

On Sep 30, 2010, at 11:16 PM, fons at kokkinizita.net wrote:

> On Thu, Sep 30, 2010 at 09:23:08PM +0200, Robin Gareus wrote:
>> Back when I was introduced to FT in some Physics lecture I was happy
>> that I was able to use it and completely forgot to check the history :)
>> Probably related to why I favored experimental Physics over Theory.
> If you're still living in Paris, make sure to visit the 'Musée des
> Arts et Métiers' one day. Quite a nice place for vintage experimental
> physics. It's also the place where the final mad scene of Umberto Eco's 
> novel "Foucault's Pendulum" is situated. The pendulum itself used to be
> there, but it's now at the Panthéon.

I know the latter of course, but I've not yet been to the Musee des Arts et Metiers. 
Thanks for the hint, I'll definitely schedule a visit.

There's so many hidden treasures here in plain sight one hardly knows where to start.

>>> And I guess this is where the windowing comes in. Calculate the spectrum
>>> of small pieces instead.
>> correct.
>> Furthermore there are different kind of windows (here a window refers to
>> a block of audio-samples) and windows can overlap. That's where it gets
>> complicated.
> Even windows won't save you from apparent madness. Imagine a signal
> consisting of all zero samples, except one every second which has
> value 1. Such a signal contains all frequencies that are a multiple 
> of 1 Hz, up to half the sample frequency. Those frequencies are present
> all the time. Now take a window of say half a second. If it includes a
> pulse you get more or less the same spectrum again. If it doesn't, you
> get nothing... even if the frequencies should be there :-)

to come back to the beginning: that's why paulstretch does allow to specify the window size.


> Ciao,
> -- 
> FA
> There are three of them, and Alleline.

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