FFTCentroid Spectral centroid


FFTCentroid.kr(chain)


Given an FFT chain, this measures the spectral centroid, which is the magnitude-weighted mean frequency, or the "centre of mass" of the spectrum. (DC is excluded.)


This can be a useful indicator of the perceptual brightness of a signal.



Example


// Very artificial example - just filtering some noise.

s.boot;

b = Buffer.alloc(s,2048,1);

(

x = {

var in, chain, freq, rq, centroid;


//freq = LFPar.kr(0.3).exprange(100, 1000);

freq = MouseY.kr(1000, 100, 1);

rq = MouseX.kr(0.01, 10);


in = BPF.ar(WhiteNoise.ar, freq, rq);


chain = FFT(b.bufnum, in);


centroid = FFTCentroid.kr(chain);


Out.ar(0, in.dup * 0.1);

centroid.poll(10);

}.play(s);

)


x.free;