bass
lead
 2 loops, 0 filters (2 workers, 1 AudioWorklet)
 tick: 0.000, time: 0.000 (120 bpm)
 
 
 
 
 

Feedback FM

A simple example of frequency modulation synthesis with feedback.

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Neat trick to make FM more powerful with very little effort.
Super cool, and it is nice to see the effect of different feedback values using a probe.
feedback
1.30
decay
0.05
input.feedback = 1.3; // min=0, max=4, step=0.001
input.decay = 0.05; // min=0.0001, max=0.1 ,step=0.0001
// Feedback frequency modulation happens when the oscillator modulates itself.
// This can lead to very interesting phenomena!
// If there is no feedback, the signal is a sine wave.
// As long as the feedback value is less than 1, everything is fine.
// When it increases beyond that, weird behaviors start to emerge,
// including chaotic behavior (which we hear as noise).
const feedbackFM = synth.def( class {
constructor(options) {
this.v = 0; // Last value of the synth
this.phase = 0;
}
process(note,env,tick,options) {
this.phase += ditty.dt * midi_to_hz(note);
// The next value depends on the last value
this.v = Math.sin(2*Math.PI*this.phase + input.feedback * this.v) * env.value;
if(options.probe && tick < 0.5) {
debug.probe("feedbackFM", this.v, 1, 5/midi_to_hz(note));
}
return this.v * 0.2;
}
}, {attack:0.0001, decay:() => input.decay, probe:false});
// A simple bass + lead pattern
ditty.bpm = 120;
const nn = [c3,f2,ab2,g2];
loop( (i) => {
feedbackFM.play(nn.ring(Math.floor(i/16)));
sleep(0.25);
}, {name:"bass"});
const nn2 = [0,c4,eb4,0,c4,f4,0,c4];
loop( (i) => {
if(nn2.ring(i)) {
feedbackFM.play(nn2.ring(i), {decay:() => 3*input.decay, probe:true});
}
sleep(0.5);
}, {name:"lead"});
 
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