diff --git a/projects/demos/musictracker.usm b/projects/demos/musictracker.usm
index 0f7836f..c4184a9 100644
--- a/projects/demos/musictracker.usm
+++ b/projects/demos/musictracker.usm
@@ -6,8 +6,6 @@
 %++ { #0001 ADD2 }
 %MOD { DUP2 DIV MUL SUB }
 %TRACK { ;track/ch1 #00 .track/active PEK #0020 MUL2 ADD2 }
-%SOUND { STH #00 .Audio/value DEO2 STHr #00 .Audio/delay DEO2 }
-%SOUND_FINISH { #00 .Audio/finish DEO }
 
 ( variables )
 
@@ -21,15 +19,16 @@
 @knob [ &x $2 &y $2 &value $1 ]
 @head [ &pos $1 ]
 @track [ &active $1 &ch1 $20 &ch2 $20 &ch3 $20 &ch4 $20 ]
-@adsr [ &ch1 $2 &ch2 $2 &ch3 $2 &ch4 $2 ]
-@volume [ &ch1 $1 &ch2 $1 &ch3 $1 &ch4 $1 ]
 
 ( devices )
 
 |00 @System [ &vector $2 &pad $6 &r $2 &g $2 &b $2 ]
 |10 @Console [ &vector $2 &pad $6 &char $1 &byte $1 &short $2 &string $2 ]
 |20 @Screen [ &vector $2 &width $2 &height $2 &pad $2 &x $2 &y $2 &addr $2 &color $1 ]
-|30 @Audio [ &pad $8 &adsr $2 &len $2 &addr $2 &volume $1 &pitch $1 ]
+|30 @Audio0 [ &vector $2 &output $1 &pad $5 &adsr $2 &len $2 &addr $2 &volume $1 &pitch $1 ]
+|40 @Audio1 [ &vector $2 &output $1 &pad $5 &adsr $2 &len $2 &addr $2 &volume $1 &pitch $1 ]
+|50 @Audio2 [ &vector $2 &output $1 &pad $5 &adsr $2 &len $2 &addr $2 &volume $1 &pitch $1 ]
+|60 @Audio3 [ &vector $2 &output $1 &pad $5 &adsr $2 &len $2 &addr $2 &volume $1 &pitch $1 ]
 |80 @Controller [ &vector $2 &button $1 &key $1 ]
 |90 @Mouse [ &vector $2 &x $2 &y $2 &state $1 &chord $1 ]
 |a0 @File [ &vector $2 &success $2 &offset $2 &pad $2 &name $2 &length $2 &load $2 &save $2 ]
@@ -56,12 +55,19 @@
 	.trkframe/x2 PEK2 .ctlframe/x2 POK2 .chnframe/y2 PEK2 .ctlframe/y2 POK2
 
 	( default settings )
-	#048c .adsr/ch1 POK2 #88 .volume/ch1 POK
-	#159d .adsr/ch2 POK2 #88 .volume/ch2 POK
-	#26ae .adsr/ch3 POK2 #88 .volume/ch3 POK
-	#260e .adsr/ch4 POK2 #88 .volume/ch4 POK
+	#048c .Audio0/adsr DEO2 #88 .Audio0/volume DEO
+	#159d .Audio1/adsr DEO2 #88 .Audio1/volume DEO
+	#26ae .Audio2/adsr DEO2 #88 .Audio2/volume DEO
+	#0000 .Audio3/adsr DEO2 #88 .Audio3/volume DEO
 
-	.volume/ch3 PEK .Audio/volume DEO
+	;square-wave .Audio0/addr DEO2
+	;square-wave/end ;square-wave SUB2 .Audio0/len DEO2
+	;triangle-wave .Audio1/addr DEO2
+	;triangle-wave/end ;triangle-wave SUB2 .Audio1/len DEO2
+	;sine-wave .Audio2/addr DEO2
+	;sine-wave/end ;sine-wave SUB2 .Audio2/len DEO2
+	;noise-wave .Audio3/addr DEO2
+	;noise-wave-end ;noise-wave SUB2 .Audio3/len DEO2
 
 	;draw-timeline JSR2
 	;draw-controls JSR2
@@ -122,10 +128,7 @@ BRK
 
 @play ( pitch -- )
 
-	.adsr/ch3 PEK2 .Audio/adsr DEO2
-	;triangle-wave .Audio/addr DEO2
-	;triangle-wave/end ;triangle-wave SUB2 .Audio/len DEO2
-	.Audio/pitch DEO
+	.Audio0/pitch DEO
 
 RTN
 
@@ -157,29 +160,29 @@ BRK
 	
 	.Mouse/x DEI2 .ctlframe/x1 PEK2 SUB2 8- 8/ SWP POP #02 DIV
 	DUP #00 NEQ ,&no-a JNZ
-		.adsr .track/active PEK #02 MUL ADD PEK
+		.Audio0/adsr .track/active PEK #10 MUL ADD DEI
 		#10 .Mouse/state DEI #10 EQU #e0 MUL ADD ADD
-		.adsr .track/active PEK #02 MUL ADD POK &no-a
+		.Audio0/adsr .track/active PEK #10 MUL ADD DEO &no-a
 	DUP #01 NEQ ,&no-d JNZ
-		.adsr .track/active PEK #02 MUL ADD PEK
+		.Audio0/adsr .track/active PEK #10 MUL ADD DEI
 		DUP #f0 AND STH #01 .Mouse/state DEI #10 EQU #0e MUL ADD ADD #0f AND STHr ADD
-		.adsr .track/active PEK #02 MUL ADD POK &no-d
+		.Audio0/adsr .track/active PEK #10 MUL ADD DEO &no-d
 	DUP #02 NEQ ,&no-s JNZ
-		.adsr .track/active PEK #02 MUL ADD #01 ADD PEK
+		.Audio0/adsr .track/active PEK #10 MUL ADD #01 ADD DEI
 		#10 .Mouse/state DEI #10 EQU #e0 MUL ADD ADD
-		.adsr .track/active PEK #02 MUL ADD #01 ADD POK &no-s
+		.Audio0/adsr .track/active PEK #10 MUL ADD #01 ADD DEO &no-s
 	DUP #03 NEQ ,&no-r JNZ
-		.adsr .track/active PEK #02 MUL ADD #01 ADD PEK
+		.Audio0/adsr .track/active PEK #10 MUL ADD #01 ADD DEI
 		DUP #f0 AND STH #01 .Mouse/state DEI #10 EQU #0e MUL ADD ADD #0f AND STHr ADD
-		.adsr .track/active PEK #02 MUL ADD #01 ADD POK &no-r
+		.Audio0/adsr .track/active PEK #10 MUL ADD #01 ADD DEO &no-r
 	DUP #05 NEQ ,&no-left JNZ
-		;volume #00 .track/active PEK ADD2 GET
+		.Audio0/volume .track/active PEK #10 MUL ADD DEI
 		#10 .Mouse/state DEI #10 EQU #e0 MUL ADD ADD
-		;volume #00 .track/active PEK ADD2 PUT &no-left
+		.Audio0/volume .track/active PEK #10 MUL ADD DEO &no-left
 	DUP #06 NEQ ,&no-right JNZ
-		;volume #00 .track/active PEK ADD2 GET
+		.Audio0/volume .track/active PEK #10 MUL ADD DEI
 		DUP #f0 AND STH #01 .Mouse/state DEI #10 EQU #0e MUL ADD ADD #0f AND STHr ADD
-		;volume #00 .track/active PEK ADD2 PUT &no-right
+		.Audio0/volume .track/active PEK #10 MUL ADD DEO &no-right
 	POP
 	( release ) #00 .Mouse/state DEO
 	;draw-controls JSR2
@@ -193,44 +196,28 @@ BRK
 	DUP #ff NEQ ,&skip1 JNZ
 		POP ,&listen2 JMP
 	&skip1
-	.adsr/ch1 PEK2 .Audio/adsr DEO2
-	.volume/ch1 PEK .Audio/volume DEO
-	;square-wave .Audio/addr DEO2
-	;square-wave/end ;square-wave SUB2 .Audio/len DEO2
-	#00 SWP ;notes ADD2 GET .Audio/pitch DEO
+	#00 SWP ;notes ADD2 GET .Audio0/pitch DEO
 	&listen2
 	;track/ch2 #00 .head/pos PEK #08 DIV ADD2 GET
 	#01 SUB
 	DUP #ff NEQ ,&skip2 JNZ
 		POP ,&listen3 JMP
 	&skip2
-	.adsr/ch2 PEK2 .Audio/adsr DEO2
-	.volume/ch2 PEK .Audio/volume DEO
-	;triangle-wave .Audio/addr DEO2
-	;triangle-wave/end ;triangle-wave SUB2 .Audio/len DEO2
-	#00 SWP ;notes ADD2 GET .Audio/pitch DEO
+	#00 SWP ;notes ADD2 GET .Audio1/pitch DEO
 	&listen3
 	;track/ch3 #00 .head/pos PEK #08 DIV ADD2 GET
 	#01 SUB
 	DUP #ff NEQ ,&skip3 JNZ
 		POP ,&listen4 JMP
 	&skip3
-	.adsr/ch3 PEK2 .Audio/adsr DEO2
-	.volume/ch3 PEK .Audio/volume DEO
-	;sine-wave .Audio/addr DEO2
-	;sine-wave/end ;sine-wave SUB2 .Audio/len DEO2
-	#00 SWP ;notes ADD2 GET .Audio/pitch DEO
+	#00 SWP ;notes ADD2 GET .Audio2/pitch DEO
 	&listen4
 	;track/ch4 #00 .head/pos PEK #08 DIV ADD2 GET
 	#01 SUB
 	DUP #ff NEQ ,&skip4 JNZ
 		POP ,&end JMP
 	&skip4
-	#0000 .Audio/adsr DEO2
-	.volume/ch4 PEK .Audio/volume DEO
-	;noise-wave .Audio/addr DEO2
-	;noise-wave-end ;noise-wave SUB2 .Audio/len DEO2
-	#00 SWP ;notes ADD2 GET #80 ORA .Audio/pitch DEO
+	#00 SWP ;notes ADD2 GET #80 ORA .Audio3/pitch DEO
 	&end
 
 RTN
@@ -400,31 +387,31 @@ RTN
 	( env )
 	.ctlframe/x1 PEK2 8+ .ctlframe/y1 PEK2 8+ #22 ;env_txt ;draw-label JSR2
 	.ctlframe/x1 PEK2 8+ .ctlframe/y1 PEK2 #0010 ADD2
-		.adsr .track/active PEK #02 MUL ADD PEK #04 SFT
+		.Audio0/adsr .track/active PEK #10 MUL ADD DEI #04 SFT
 		;draw-knob JSR2
 	.ctlframe/x1 PEK2 #0018 ADD2 .ctlframe/y1 PEK2 #0010 ADD2
-		.adsr .track/active PEK #02 MUL ADD PEK #0f AND
+		.Audio0/adsr .track/active PEK #10 MUL ADD DEI #0f AND
 		;draw-knob JSR2
 	.ctlframe/x1 PEK2 #0028 ADD2 .ctlframe/y1 PEK2 #0010 ADD2
-		.adsr .track/active PEK #02 MUL ADD #01 ADD PEK #04 SFT
+		.Audio0/adsr .track/active PEK #10 MUL ADD #01 ADD DEI #04 SFT
 		;draw-knob JSR2
 	.ctlframe/x1 PEK2 #0038 ADD2 .ctlframe/y1 PEK2 #0010 ADD2
-		.adsr .track/active PEK #02 MUL ADD #01 ADD PEK #0f AND
+		.Audio0/adsr .track/active PEK #10 MUL ADD #01 ADD DEI #0f AND
 		;draw-knob JSR2
 	( vol )
 	.ctlframe/x1 PEK2 #0058 ADD2 .ctlframe/y1 PEK2 8+ #22 ;vol_txt ;draw-label JSR2
 	.ctlframe/x1 PEK2 #0058 ADD2 .ctlframe/y1 PEK2 #0010 ADD2
-		;volume #00 .track/active PEK ADD2 GET #04 SFT
+		.Audio0/volume .track/active PEK #10 MUL ADD DEI #04 SFT
 	;draw-knob/force JSR2
 	.ctlframe/x1 PEK2 #0068 ADD2 .ctlframe/y1 PEK2 #0010 ADD2
-		;volume #00 .track/active PEK ADD2 GET #0f AND
+		.Audio0/volume .track/active PEK #10 MUL ADD DEI #0f AND
 	;draw-knob/force JSR2
 
 RTN
 
 @draw-vu ( -- )
 	.ctlframe/x1 PEK2 #0088 ADD2 .ctlframe/y1 PEK2 #0010 ADD2
-		.Audio/volume DEI DUP STH #04 SFT
+		.Audio0/output .track/active PEK #10 MUL ADD DEI DUP STH #04 SFT
 	;draw-knob/force JSR2
 	.ctlframe/x1 PEK2 #0098 ADD2 .ctlframe/y1 PEK2 #0010 ADD2
 		STHr #0f AND
@@ -513,8 +500,8 @@ RTN
 
 RTN
 
-@ch1_txt [ "SQR  00 ]
-@ch2_txt [ "TRI  00 ]
+@ch1_txt [ "SQR 20 00 ]
+@ch2_txt [ "TRI 20 00 ]
 @ch3_txt [ "SINE 00 ]
 @ch4_txt [ "DRUM 00 ]
 @env_txt [ "Envelope 00 ]
diff --git a/projects/demos/piano.usm b/projects/demos/piano.usm
index 91f4c7e..2b1d2ba 100644
--- a/projects/demos/piano.usm
+++ b/projects/demos/piano.usm
@@ -12,7 +12,7 @@
 |00 @System     [ &vector $2 &pad      $6 &r      $2 &g     $2 &b      $2 ]
 |10 @Console    [ &pad    $8 &char     $1 &byte   $1 &short $2 &string $2 ]
 |20 @Screen     [ &vector $2 &width    $2 &height $2 &pad   $2 &x      $2 &y     $2 &addr $2 &color $1 ]
-|30 @Audio      [ &pad    $8 &adsr     $2 &length $2 &addr  $2 &volume $1 &pitch $1 ]
+|30 @Audio      [ &vector $2 &output   $1 &pad    $5 &adsr     $2 &length $2 &addr  $2 &volume $1 &pitch $1 ]
 |70 @Midi       [ &vector $2 &message  $2 ]
 |80 @Controller [ &vector $2 &button   $1 &key    $1 ]
 |90 @Mouse      [ &vector $2 &x        $2 &y      $2 &state $1 &chord  $1 ]
@@ -87,9 +87,8 @@ BRK
 	
 	.wave-view/x1 PEK2 #0028 ADD2 .Screen/x DEO2
 	.wave-view/y1 PEK2 #0010 SUB2 .Screen/y DEO2
-	.Audio/volume DEI #04 SFT TOS #0008 MUL2 ;meter ADD2 .Screen/addr DEO2
+	.Audio/output DEI #04 SFT TOS #0008 MUL2 ;meter ADD2 .Screen/addr DEO2
 	#21 .Screen/color DEO
-	#88 .Audio/volume DEO
 
 
 BRK
diff --git a/src/apu.c b/src/apu.c
index cceabb6..6f4c848 100644
--- a/src/apu.c
+++ b/src/apu.c
@@ -54,8 +54,8 @@ apu_render(Apu *c, Sint16 *sample, Sint16 *end)
 			c->i %= c->len;
 		}
 		s = (Sint8)(c->addr[c->i]) * envelope(c, c->age++);
-		*sample++ += s * c->volume_l / 0x180;
-		*sample++ += s * c->volume_r / 0x180;
+		*sample++ += s * c->volume[0] / 0x180;
+		*sample++ += s * c->volume[1] / 0x180;
 	}
 }
 
@@ -81,17 +81,13 @@ apu_start(Apu *c, Uint16 adsr, Uint8 pitch)
 }
 
 Uint8
-apu_get_vu(Apu *c, Apu *end)
+apu_get_vu(Apu *c)
 {
 	size_t i;
-	Sint32 sum[2] = {0, 0};
-	for(; c < end; ++c) {
-		if(!c->advance) continue;
-		sum[0] += envelope(c, c->age) * c->volume_l;
-		sum[1] += envelope(c, c->age) * c->volume_r;
-	}
+	Sint32 sum[2];
+	if(!c->advance || !c->period) return 0;
 	for(i = 0; i < 2; ++i) {
-		sum[i] /= 0x800;
+		sum[i] = envelope(c, c->age) * c->volume[i] / 0x800;
 		if(sum[i] > 0xf) sum[i] = 0xf;
 	}
 	return (sum[0] << 4) | sum[1];
diff --git a/src/apu.h b/src/apu.h
index 9a4757b..4decddf 100644
--- a/src/apu.h
+++ b/src/apu.h
@@ -20,10 +20,10 @@ typedef struct {
 	Uint8 *addr;
 	Uint32 count, advance, period, age, a, d, s, r;
 	Uint16 i, len;
-	Sint8 volume_l, volume_r;
+	Sint8 volume[2];
 	Uint8 pitch, repeat;
 } Apu;
 
 void apu_render(Apu *c, Sint16 *sample, Sint16 *end);
 void apu_start(Apu *c, Uint16 adsr, Uint8 pitch);
-Uint8 apu_get_vu(Apu *c, Apu *end);
+Uint8 apu_get_vu(Apu *c);
diff --git a/src/emulator.c b/src/emulator.c
index 29d36bf..70cdc2e 100644
--- a/src/emulator.c
+++ b/src/emulator.c
@@ -25,7 +25,7 @@ static SDL_Texture *gTexture;
 static Ppu ppu;
 static Apu apu[POLYPHONY];
 static Mpu mpu;
-static Device *devscreen, *devmouse, *devctrl, *devmidi;
+static Device *devscreen, *devmouse, *devctrl, *devmidi, *devaudio0;
 
 Uint8 zoom = 0, debug = 0, reqdraw = 0;
 
@@ -251,26 +251,21 @@ file_talk(Device *d, Uint8 b0, Uint8 w)
 static void
 audio_talk(Device *d, Uint8 b0, Uint8 w)
 {
-	Apu *c;
-	if(!w) {
-		if(b0 == 0xe) d->dat[0xe] = apu_get_vu(apu, apu + POLYPHONY);
-		return;
+	Apu *c = &apu[d - devaudio0];
+	if(!w && b0 == 0x2) {
+		d->dat[0x2] = apu_get_vu(c);
 	}
-	c = &apu[d->dat[0x7] % POLYPHONY];
-	SDL_LockAudioDevice(audio_id);
-	if(b0 == 0x1) c->period -= (Sint16)mempeek16(d->dat, 0x0);
-	if(b0 == 0x3 || b0 == 0xf) c->len = mempeek16(d->dat, (b0 & 0x8) | 0x2);
-	if(b0 == 0x5 || b0 == 0xf) c->addr = &d->mem[mempeek16(d->dat, (b0 & 0x8) | 0x4)];
-	if(b0 == 0x6 || b0 == 0xf) {
-		c->volume_l = d->dat[(b0 & 0x8) | 0x6] >> 4;
-		c->volume_r = d->dat[(b0 & 0x8) | 0x6] & 0xf;
-	}
-	if(b0 == 0xf) {
+	if(w && b0 == 0xf) {
+		SDL_LockAudioDevice(audio_id);
+		c->period -= (Sint16)mempeek16(d->dat, 0x0);
+		c->len = mempeek16(d->dat, 0xa);
+		c->addr = &d->mem[mempeek16(d->dat, 0xc)];
+		c->volume[0] = d->dat[0xe] >> 4;
+		c->volume[1] = d->dat[0xe] & 0xf;
 		c->repeat = !(d->dat[0xf] & 0x80);
 		apu_start(c, mempeek16(d->dat, 0x8), d->dat[0xf] & 0x7f);
-		d->dat[0x7]++;
+		SDL_UnlockAudioDevice(audio_id);
 	}
-	SDL_UnlockAudioDevice(audio_id);
 }
 
 void
@@ -378,10 +373,10 @@ main(int argc, char **argv)
 	portuxn(&u, 0x0, "system", system_talk);
 	portuxn(&u, 0x1, "console", console_talk);
 	devscreen = portuxn(&u, 0x2, "screen", screen_talk);
-	portuxn(&u, 0x3, "audio", audio_talk);
-	portuxn(&u, 0x4, "---", nil_talk);
-	portuxn(&u, 0x5, "---", nil_talk);
-	portuxn(&u, 0x6, "---", nil_talk);
+	devaudio0 = portuxn(&u, 0x3, "audio0", audio_talk);
+	portuxn(&u, 0x4, "audio1", audio_talk);
+	portuxn(&u, 0x5, "audio2", audio_talk);
+	portuxn(&u, 0x6, "audio3", audio_talk);
 	devmidi = portuxn(&u, 0x7, "midi", midi_talk);
 	devctrl = portuxn(&u, 0x8, "controller", nil_talk);
 	devmouse = portuxn(&u, 0x9, "mouse", nil_talk);