// our UGen patch
SinOsc x => dac;

// set frequency
440 => x.freq;
// let time pass
1::second => now;

// set frequency
880 => x.freq;
// set gain
.75 => x.gain;
// let time pass
1::second => now;

// set frequency
1760 => x.freq;
// set gain
.5 => x.gain;
// let time pass
1.5::second => now;