Classes | UGens > FFT

Unpack1FFT : UGen : AbstractFunction : Object

Unpack a single value (magnitude or phase) from an FFT chain

Unpack1FFT(chain, bufsize, binindex, whichmeasure=0)


Takes an FFT chain and extracts a single scalar value as a demand-rate stream. To call it you need a "demander" which fires whenever the FFT chain fires - this is normally achieved using PackFFT but can also be done using Demand.

NOTE: The main purpose of this UGen is as a component in pvcollect, pvcalc, and pvcalc2 processes. You're welcome to use it on its own - the example below shows basic usage. But most people won't typically need to use it directly.

Class Methods, bufsize, binindex, whichmeasure: 0)



an FFT chain


the size of the expected input FFT frames


the integer index of the bin you want to query


0 for magnitude and 1 for phase. None of these arguments can be modulated.

Inherited class methods

Instance Methods

Inherited instance methods


    c =, Platform.resourceDir +/+ "sounds/a11wlk01.wav");

// Let's extract the DC component - i.e. the magnitude at index zero.
x = {
    var fftsize = 1024;
    var sig, chain, unp;
    sig =, c,, loop: 1);
    chain = FFT(LocalBuf(fftsize), sig);

    unp = Unpack1FFT(chain, b.numFrames, 0, 0);

    // Demand some data from the unpacker>=0, 0, unp).poll(chain>=0, "unpacked value");