SuperCollider CLASSES (extension)

PV_SpectralMap
ExtensionExtension

Maps the spectral envelope of one FFT process onto another

Description

Acts as a spectral filter.

WARNING: Use of a FFTs with a large window size may cause CPU spikes.

Class Methods

*new (buffer, specBuffer, floor: 0, freeze: 0, mode: 0, norm: 0, window: 0)

Arguments:

buffer

The FFT buffer to filter.

specBuffer

The FFT buffer to derive the spectral curve from.

floor

The spectral curve is a normalized representation of the magnitudes in specBuffer (between 0 and 1). if floor > 0, mags in the spectral curve BELOW this number are also zeroed out.

freeze

If > 0, freeze the current spectral curve. The 'floor' parameter is ignored once the spectral curve is frozen.

mode

If mode == 0, PV_SpectralMap does not have any effect. > 0 acts as a bandpass filter, < 0 a bandreject.

norm

Normalization mode. If <=0, the specBuffer's magnitudes are normalized on a frame by from basis. >0, normalized according to the the sum of the FFT window's sample values.

window

The window used for the FFT - this will effect scaling if norm is > 0.

Inherited class methods

Instance Methods

Inherited instance methods

Examples

s.boot;
z = Buffer.read(s, Platform.resourceDir +/+ "sounds/a11wlk01.wav");

(
x = SynthDef(\specMap, {arg sndBuf, freeze = 0;
    var a, b, chain1, chain2, out;
    a = LocalBuf.new(2048);
    b = LocalBuf.new(2048);
    chain1 = FFT(a, LFSaw.ar(120)); // to be filtered
    chain2 = FFT(b, PlayBuf.ar(1, z, 1, loop: 1));
    // mouse x to play with floor.
    chain1 = PV_SpectralMap(chain1, chain2, 0.0, freeze, MouseX.kr(-1, 1), 1);
    out = IFFT(chain1);
    Out.ar(0, out.dup);
}).play(s, [\sndBuf, z, \freeze, 0])
)

x.set(\freeze, 1)
x.set(\freeze, 0);

x.free;

z.free;