A cubic-interpolating sound generator based on the difference equations:
x(n+1) = sin(im * y(n) + fb * x(n))
y(n+1) = (a * y(n) + c) % 2pi
This uses a linear congruential function to drive the phase indexing of a sine wave. For im = 1, fb = 0, and a = 1 a normal sinewave results.
sclang code translation:
(var im = 1, fb = 0.1, a = 1.1, c = 0.5, xi = 0.1, yi = 0.1, size = 64;plot(size.collect { xi = sin((im * yi) + (fb * xi)); yi = (a * yi + c) % 2pi; xi });)| freq |
Iteration frequency in Hertz |
| im |
Index multiplier amount |
| fb |
Feedback amount |
| a |
Phase multiplier amount |
| c |
Phase increment amount |
| xi |
Initial value of x |
| yi |
Initial value of y |
xxxxxxxxxx// default initial params{ FBSineC.ar(SampleRate.ir/4) * 0.2 }.play(s);xxxxxxxxxx// increase feedback{ FBSineC.ar(SampleRate.ir, 1, Line.kr(0.01, 4, 10), 1, 0.1) * 0.2 }.play(s);xxxxxxxxxx// increase phase multiplier{ FBSineC.ar(SampleRate.ir, 1, 0, XLine.kr(1, 2, 10), 0.1) * 0.2 }.play(s);xxxxxxxxxx// modulate frequency and index multiplier{ FBSineC.ar(LFNoise2.kr(1, 1e4, 1e4), LFNoise2.kr(1,16,17), 1, 1.005, 0.7) * 0.2 }.play(s);xxxxxxxxxx// randomly modulate params({ FBSineC.ar( LFNoise2.kr(1, 1e4, 1e4), LFNoise2.kr(1, 32, 33), LFNoise2.kr(1, 0.5), LFNoise2.kr(1, 0.05, 1.05), LFNoise2.kr(1, 0.3, 0.3)) * 0.2 }.play(s);)