<info>
Simple low-pass filter
"tone" or butterworth.
gain is post-balance

Alexandre Burton, 1996
</info>
<tk_interface>
cgraph hifreq -label "Frequency\nCut-off" -unit Hz -rel log -min 20 -max 20000 -init 2000 
csepar
cgraph gain -label "Gain" -rel log -min .1 -max 10 -init 1 
ctoggle balance  -label "Balance power with input file"
ctoggle butter  -label "Use Butterworth filters"

cfilein source
</tk_interface>
<mono>
		instr 1

kfac	=	[sinfo source sr]/sr
ain	diskin	"[source]", kfac, [offsource]

if	(gkbutter == 1) igoto butter

afilt	tone	ain, gkhifreq
afilt	tone	ain, gkhifreq
goto bal

butter:
afilt	butterlp	ain, gkhifreq
afilt	butterlp	ain, gkhifreq

bal:
if 	(gkbalance == 0 ) goto nobal
	afilt	balance afilt, ain

nobal:
	out	afilt*gkgain
	
			endin
</mono>
<stereo>
		instr 1


kfac	=	[sinfo source sr]/sr
aing, aind diskin "[source]", kfac, [offsource]

kbut = gkbutter
kbal = gkbalance

if	(kbut == 1) igoto butter  
afiltg	tone	aing, gkhifreq
afiltd	tone	aind, gkhifreq
afiltg	tone	afiltg, gkhifreq
afiltd	tone	afiltd, gkhifreq
goto bal

butter:
afiltg1	butterlp	aing, gkhifreq
afiltd1	butterlp	aind, gkhifreq
afiltg	butterlp	afiltg1, gkhifreq
afiltd	butterlp	afiltd1, gkhifreq


bal:
if 	(kbal == 0) goto nobal
	afiltg	balance afiltg, aing
	afiltd	balance afiltd, aind

nobal:
	outs	afiltg*gkgain, afiltd*gkgain
	
			endin
</stereo>
<quad>

</quad>
<score>
#minimum
</score>
