Designing Sound in SuperCollider/Motors

Fig 44.5: Motor

Contains the subpatches shown in fig 44.2, 44.3, 44.4 and 44.6.

(
{ 
	
  |	// arguments range: 0.0 - 1.0
  	runtime 	= 0.2, 
	statorLevel	= 0.7, 	
	brushLevel	= 0.9,	
	rotorLevel	= 0.6, 	
	maxSpeed	= 0.3,	
	volume		= 0.5,
	tubeRes		= 0.2
  |
	
	var motorEnv, motorEnv1, motorEnv2, motor, rotor, drive, stator, resonance;

	// fig 44.2: Speed Control Envelope
	motorEnv = (Line.ar(0,1,runtime * 20, doneAction:2)) * 2;
	motorEnv1 = (1 - motorEnv.min(1)).pow(6); // fast growing curve
	motorEnv2 = motorEnv.max(1) - 1; // linear decay
	motorEnv = (motorEnv1 + motorEnv2) * (-1) + 1;
	
	drive = motorEnv * (maxSpeed * (-2000));
	drive = LFSaw.ar(drive, 1, 0.5, 0.5);
	
	// fig 44.3: Rotor
	rotor = WhiteNoise.ar;
	rotor = BPF.ar(rotor, 4000, 1.reciprocal) * brushLevel;
	rotor = (rotor + (rotorLevel * 0.2)) * drive.pow(4);
	
	// fig 44.4: Stator
	stator = (Wrap.ar(drive * 2) * 2pi).cos;
	// notice the difference in SC between (stator * stator) and stator.pow(2)
	// to achieve the desired sound result from the book, use (stator * stator)
	// stator = stator.pow(2) + 1; // equals stator ** 2 + 1; 
	stator = (stator * stator) + 1; 
	stator = (1 / stator - 0.5) * statorLevel;
	
	// fig 44.6: FM body resonance
	resonance = SinOsc.ar(178) * drive + motorEnv;
	resonance = (resonance * 2pi).cos;
	resonance = (resonance - OnePole.ar(resonance, exp(-2pi * (180 * SampleDur.ir))));
	resonance = (resonance - OnePole.ar(resonance, exp(-2pi * (180 * SampleDur.ir))));
	resonance = resonance * tubeRes;
	
	motor = motorEnv * (rotor + stator + resonance);
	motor = (motor * volume).dup;
	
}.play
)