[PD] fft -> get to know of requested frequency range

Christian Klotz list_pd at deviation.de
Mon Jul 26 00:33:35 CEST 2004

On Jul 23, 2004, at 1:17 PM, IOhannes m zmoelnig wrote:

> Christian Klotz wrote:
>> hi,
>> I currently try to analyse sound input (using microphone) and check 
>> if the sound contains a definite frequency range. so if there is a 
>> frequency range of 10,000 to 11,000 hz in there it should do a bang 
>> for example. So I tried a little bit with fft and tabwrite but at the 
>> moment I stuck. Does anyone of you have an idea how to solve the 
>> problem?
>> thanks, cheers
> yes, try fft and tabwrite....
> to be honest: why not using a [bp~] for such a task ?
> if you really need fft's, be sure that you know that the signals 
> coming out of [rfft~] are real and imaginary parts of a complex 
> signal.
> since you need the amplitude of the complex signal you will have to 
> calculate it yourself.
> mfg.as.dr
> IOhannes

so I tried a bit with [bp~] but the problem was, that the amplitudes I 
got were pretty high (after comparision with incoming signal) - dont't 
know why. So I still don't know how to handle the incoming audio to get 
to know if a specified frequency range is contained by the the audio 
in. That's why I tried fft once more, but I have no idea how to 
calculate the data [rfft~] is giving to me. Does anybody of you have an 
thanks, mfg

More information about the Pd-list mailing list