s.boot;

// now in stereo

~audiobus = Bus.audio(s,2); // two channels
~controlbus = Bus.control(s);

SynthDef( \soundsource, { Out.ar( ~audiobus.index, [WhiteNoise.ar,SinOsc.ar] ) } ).play;

SynthDef( \controlsource, { Out.kr( ~controlbus.index, SinOsc.kr( 3 ).range(0,1) ) } ).play;

(
SynthDef( \combined, {
	var soundin = In.ar( ~audiobus.index, 2 ); // so soundin is an array of two channels now
	var controlin = In.kr( ~controlbus.index );

	// amplitude modulate the white noise with the incoming control signal
	var result = soundin * controlin;

	// multiply by 0.1 so it's not too loud
	Out.ar( 0, result * 0.1 );

} ).play(addAction:\addToTail);
// the addToTail is important here -- need to have the combined process after
// the audio source and control are generated; otherwise the busses will be zero
// when they're read since they only get filled later on in the dsp chain.
)