[PD] [fft] frequency select

sme marius.schebella at chello.at
Tue Apr 30 21:19:17 CEST 2002


hi, your idea is correct, though slightly unprecise. 
to get a synchronized bang after each block of 1024 samples you can use the "block~"-object
if you use a "tabsend~"-object, then the fft-data is sent countinuously. to read a certain frequency you could also use the bangs from bang~
the channel 0 will give the d.c. one would be samplerate/blocksize (with 44.1k this would be 43Hz) 2 would be 86Hz and so on. 512 should be 22050Hz, the nyquist-frequency, but the highest frequency the fft-object of pd gives you is 511 (22007Hz).
do you need a table? NO. you can use "pack~ 1024" and "packel [number]" with number the default channel you want to watch.
your other question, detecting the loudest frequency, could be done with either one of the zexy objects or could be calculated in realtime on signal-way. but for frequency-detection you can also use "bonk", one of millers specials...
sme. 


  ----- Original Message ----- 
  From: Andre Schmidt 
  To: PD-LiST 
  Sent: Tuesday, April 30, 2002 8:03 PM
  Subject: [PD] [fft] frequency select


  hi,

  i just started on fft and wondered if this [attachment] is the best/right way to analyze a selected frequency... the fft part is ripped from the examples (dunno which it was). then i just select with tabread/index the frequency i need...

  do i NEED a table for this task ???

  thnx
  -andre
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