0.15 => dac.gain;

SqrOsc foo => LPF lpf => ADSR adsr => dac;
220 => foo.freq;
3000 => lpf.freq;
adsr.set(10::ms, 500::ms, 0.5, 100::ms);
adsr.keyOn();
1::second => now;
adsr.keyOff();
500::ms => now;

440 => foo.freq;
3000 => lpf.freq;
adsr.set(5::ms, 200::ms, 0, 100::ms);
adsr.keyOn();
1::second => now;
adsr.keyOff();
500::ms => now;