## sine waves from FFT analysis

Feb 11 2010 | 5:52 pm
hi board
could anyone direct me into the right direction with this;
i want to analyze the spectral components of a signal, and resynthesize it with a fft object - but be able to decide how many sinewave components are used to reconstruct the original signal!
something like reducing the "resolution" of the resynthesis. i'd like to hear a signal represented by 2 up to lets say 250 sine waves...
any ideas?

• Feb 11 2010 | 5:54 pm
ehm... maybe this is a little unclear...
what i want is a patch that can represent a signal in variable numbers of sinewaves.
how would a wookiee growl sound using only 3 sinewaves to resynthesize it? what would it sound like with 250 sinewave components?
• Feb 11 2010 | 7:17 pm
Have you seen the forbidden-planet patch in the examples folder? It sounds like you could do what you want with a few adjustments of that patch. It sounds like the same concept to me. If you want to re-synthesize with only 250 sine waves, then you need to decide which 250 to let pass, which is essentially equalization.
• Feb 11 2010 | 11:08 pm
cool, ill check that out!
this however woul not be equalization, because the possible sine waves would always be spread evenly over the spectrum. i don't want to simply x out certain frequencies (bands)
• Feb 12 2010 | 1:02 am
[oscbank~] might also be worth checking into, if you're OK with its frequency spread limitations. Otherwise you could use [bpatcher] or [poly~] with as many instances as you want, one cycle~ in each, and generate the frequencies and amplitudes from them. With the right scale factor *~ available to each, you can easily send a fundamental frequency and know that all your "partials" (of whatever scale factor you want) will relate to the original.
I think Wookies use some square waves too...as you know, they're kind of rough around the edges :)
• Feb 12 2010 | 11:12 am
this is sdif based but might help you get some ideas. [sinusoids~] and [SDIF-buffer]+[SDIF-tuples] will do what you described, given that you have analysis files first (.sdif) by Spear or something alike.
• Feb 12 2010 | 3:40 pm
apparently miller puckettes fiddle~ gives me exactly the sinusoidal components i need!!
thanks for the help.
-klive
• Feb 15 2010 | 6:44 pm
The iana~ object is what you want: