SuperCollider CLASSES


Spectral Flatness measure
Inherits from: UGen : AbstractFunction : Object


Given an FFT chain this calculates the Spectral Flatness measure, defined as a power spectrum's geometric mean divided by its arithmetic mean. This gives a measure which ranges from approx 0 for a pure sinusoid, to approx 1 for white noise.

The measure is calculated linearly. For some applications you may wish to convert the value to a decibel scale - an example of such conversion is shown below.

Class Methods

*kr (buffer)



an FFT chain.

Inherited class methods

Instance Methods

Inherited instance methods


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

{ // Example - vary mixture of white noise and pure tone with the mouse
var in, chain, flat, flatdb, flatdbsquish;
in =,,,1));
chain = FFT(b, in);, in * 0.1);

flat =;

flatdb = 10 * flat.log; // Convert to decibels
flatdbsquish =, -45, -1.6, 0, 1).max(-10); // Rescale db roughly to 0...1.

flat.poll(10, "flatness: ");
flatdb.poll(10, "flatness (db): ");, [flat, flatdbsquish]);

{ // Now try with your own voice
var in, chain;
in =[0,1]).mean;
chain = FFT(b, in);, [in,, "flatness: ")]);