[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
idea?
thanks, mfg
Christian
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