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

Christian Klotz list_pd at deviation.de
Fri Jul 23 14:05:26 CEST 2004

On 23.07.2004, at 13:17, 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

I am new to sound analysis and started using fft because I thought 
about doing some other things with the sound analysis later. My problem 
is - even after reading the fft documentation - that I dont know how to 
handle the real and imaginary data. The main question for me is which 
objects or arguments have to be set to check if the sound contains the 
requestd frequency range.

Christian Klotz

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