BRF 2nd order Butterworth band reject filter

BRF.ar(in, freq, rq, mul, add)

A second order low pass filter. 

in - input signal to be processed

freq - cutoff frequency in Hertz.

rq - the reciprocal of Q.  bandwidth / cutoffFreq. 

{ BRF.ar(Saw.ar(200,0.1), FSinOsc.kr(XLine.kr(0.7,300,20),0,3800,4000), 0.3) }.play;

{ BRF.ar(Saw.ar(200,0.5), MouseX.kr(100, 10000, 1), 0.3) }.play;

// BRF on control signals:

(

{ var vib = BRF.kr(SinOsc.kr([1, 3, 10], 0, [1, 0.5, 0.25]).sum, MouseX.kr(1, 10, 1), 0.3);

SinOsc.ar(vib * 200 + 600) * 0.2 }.play;

)