;	lowpass filter

sr	=	44100
kr	=	4410
ksmps	=	10
nchnls	=	1

instr	1	; generate white noise
	imaxamp	=	32767 ; maximum allowable amplitude of noise
	kenv	linen	p4, 0.05, p3, 0.05 ; envelope, with p4 between 0 and 1
	anoise	rand	imaxamp	; white noise
	gasource	=	kenv*anoise	; control amplitude of noise with envelope
	; and put it in a global variable to use as a source sound for filter
endin

instr	2	; generate band-limited pulse train
	iharms	=	(sr*0.5)/p5 ; keep number of harmonics within Nyquist rate
	iharms	limit	iharms, 1, 16
	imaxamp	=	32767 ; maximum allowable amplitude of noise
	kenv	linen	p4*imaxamp, 0.05, p3, 0.05 ; envelope, with p4 between 0 and 1
	gasource	buzz	kenv, p5, iharms, 1 ; band-limited pulse train (within Nyquist rate)
	; put it in a global variable to use as a source sound for filter
endin

instr	3	; filter a sound with a sweeping lopass filter
	kfreq	line	p4, p3, p5	; sweep the cutoff frequency
	kq	line	p6, p3, p7
	aout	lowpass2	gasource, kfreq, kq
		out aout
endin