ADSR Env Doesn't Work With SinOSC

Questions
1

With this synth, the ADSR envelope doesn’t work-- the sound starts at full amplitude, then cuts off immediately when ‘gate’ is set to 0. If I simply change the oscillator to Saw.ar, the envelope works as expected…what’s going on here?

SynthDef("mysynth", {
	arg freq = 110, out = 0, amp = 0.6, gate = 1, atk = 3.0, decay = 2.0, sustain = 0.0, rel = 2.0;
	var env = EnvGen.kr(Env.adsr(atk, decay, sustain, rel), gate, doneAction:2);
	Out.ar(out, SinOsc.ar([freq, freq+1], amp * env));
}).add;
2

There are 2 mistakes :

  • sustain is not duration, but a level. Therefore it should not be 0.
  • the second parameter of SinOsc is phase, not amplitude.

The following works:

	arg freq = 510, out = 0, amp = 0.6, gate = 1, atk = 3.0, decay = 2.0, sustain = 0.5, rel = 2.0;
	var env = EnvGen.kr(Env.adsr(atk, decay, sustain, rel), gate, doneAction:2);
	Out.ar(out, SinOsc.ar([freq, freq+1], 0, amp * env));
}).add;
3

Ah HA! I had forgotten about the ‘phase’ parameter for SinOsc.

Thanks!
Bryan

4

Elsewhere, Nathan has proposed that we should avoid using the mul and add arguments, and just write * and + instead.

I don’t think it’s necessary to be too strict about it, but this case supports his idea:

  • If you use mul, then you have to remember which argument is mul = one more opportunity for bugs.

  • If you write SinOsc.ar(...) * env, then there is absolutely no room for doubt.

hjh