04-building-lfo.py - Audio control of parameters.

One of the most important thing with computer music is the trajectories taken by parameters over time. This is what gives life to the synthesized sound.

One way to create moving values is by connecting a low frequency oscillator to an object’s attribute. This script shows that process.

Other possibilities that will be covered later use random class objects or feature extraction from an audio signal.

from pyo import *

s = Server().boot()

# Creates a noise source
n = Noise()

# Creates an LFO oscillating +/- 500 around 1000 (filter's frequency)
lfo1 = Sine(freq=0.1, mul=500, add=1000)
# Creates an LFO oscillating between 2 and 8 (filter's Q)
lfo2 = Sine(freq=0.4).range(2, 8)
# Creates a dynamic bandpass filter applied to the noise source
bp1 = ButBP(n, freq=lfo1, q=lfo2).out()

# The LFO object provides more waveforms than just a sine wave

# Creates a ramp oscillating +/- 1000 around 12000 (filter's frequency)
lfo3 = LFO(freq=0.25, type=1, mul=1000, add=1200)
# Creates a square oscillating between 4 and 12 (filter's Q)
lfo4 = LFO(freq=4, type=2).range(4, 12)
# Creates a second dynamic bandpass filter applied to the noise source
bp2 = ButBP(n, freq=lfo3, q=lfo4).out(1)