diff --git a/Makefile b/Makefile
index 17c1e126b..477953465 100644
--- a/Makefile
+++ b/Makefile
@@ -97,6 +97,7 @@ $(B_DIR)/lib/ultra/libc/llcvt.o: MIPSISET := -mips3 -32
 $(B_DIR)/lib/lib_2fba0.o: OPT_LVL := -g
 $(B_DIR)/lib/lib_30ce0.o: OPT_LVL := -g
 $(B_DIR)/lib/mp3.o: OPT_LVL := -g
+$(B_DIR)/lib/speaker.o: OPT_LVL := -g
 $(B_DIR)/lib/lib_3a100.o: OPT_LVL := -g
 $(B_DIR)/lib/lib_3d280.o: OPT_LVL := -g
 $(B_DIR)/lib/lib_3e730.o: OPT_LVL := -g
diff --git a/src/include/constants.h b/src/include/constants.h
index c6beccc73..6dbf2cc13 100644
--- a/src/include/constants.h
+++ b/src/include/constants.h
@@ -3450,6 +3450,11 @@
 #define SPAWNFLAG_RTRACKED            0x00008000
 #define SPAWNFLAG_BLUESIGHT           0x00010000
 
+#define SPEAKERMODE_MONO      1
+#define SPEAKERMODE_STEREO    2
+#define SPEAKERMODE_HEADPHONE 3
+#define SPEAKERMODE_SURROUND  4
+
 #define SPECIALDIE_NONE        0
 #define SPECIALDIE_FALLBACK    1
 #define SPECIALDIE_ROLL1       2
diff --git a/src/include/lib/speaker.h b/src/include/lib/speaker.h
index a57d1dc6a..725904813 100644
--- a/src/include/lib/speaker.h
+++ b/src/include/lib/speaker.h
@@ -4,7 +4,7 @@
 #include "data.h"
 #include "types.h"
 
-void speaker00034030(s32 arg0);
+void speakersSetMode(u8 mode);
 void speaker00034104(s32 index, s32 arg1);
 
 #endif
diff --git a/src/include/types.h b/src/include/types.h
index af51cd434..679c67794 100644
--- a/src/include/types.h
+++ b/src/include/types.h
@@ -7053,10 +7053,9 @@ struct mp3vars {
 };
 
 struct var8009c340 {
-	u8 unk00;
-	u8 unk01;
-	u8 unk02;
-	u8 unk03;
+	u8 surround;
+	u8 mono;
+	u8 headphone;
 };
 
 struct var80095210 {
diff --git a/src/lib/mp3.c b/src/lib/mp3.c
index cf7fff402..d6cd15450 100644
--- a/src/lib/mp3.c
+++ b/src/lib/mp3.c
@@ -791,10 +791,10 @@ void func00038924(struct mp3vars *vars)
 		vars->var8009c39e = vars->var8009c3e4;
 
 		if (vars->var8009c39c != vars->var8009c3ec) {
-			if (var8009c340.unk02) {
+			if (var8009c340.headphone) {
 				vars->var8009c39c = ((s16)(vars->var8009c3ec & 0x7f) >> 1) + 32;
 			} else {
-				if (var8009c340.unk01) {
+				if (var8009c340.mono) {
 					vars->var8009c39c = 64;
 				} else {
 					vars->var8009c39c = vars->var8009c3ec;
diff --git a/src/lib/snd.c b/src/lib/snd.c
index 51d14e6bd..9cddda5f3 100644
--- a/src/lib/snd.c
+++ b/src/lib/snd.c
@@ -1695,16 +1695,16 @@ void sndSetSoundMode(s32 mode)
 
 	switch (mode) {
 	case SOUNDMODE_MONO:
-		speaker00034030(1);
+		speakersSetMode(SPEAKERMODE_MONO);
 		break;
 	case SOUNDMODE_STEREO:
-		speaker00034030(2);
+		speakersSetMode(SPEAKERMODE_STEREO);
 		break;
 	case SOUNDMODE_HEADPHONE:
-		speaker00034030(3);
+		speakersSetMode(SPEAKERMODE_HEADPHONE);
 		break;
 	case SOUNDMODE_SURROUND:
-		speaker00034030(4);
+		speakersSetMode(SPEAKERMODE_SURROUND);
 		break;
 	}
 
diff --git a/src/lib/speaker.c b/src/lib/speaker.c
index 903f545d7..ba9ff7fb2 100644
--- a/src/lib/speaker.c
+++ b/src/lib/speaker.c
@@ -22,68 +22,30 @@ struct var8009c340 var8009c340;
 u32 var8009c344;
 u32 var8009c348;
 
-GLOBAL_ASM(
-glabel speaker00034030
-/*    34030:	27bdffd8 */ 	addiu	$sp,$sp,-40
-/*    34034:	afbf001c */ 	sw	$ra,0x1c($sp)
-/*    34038:	afa40028 */ 	sw	$a0,0x28($sp)
-/*    3403c:	afb00018 */ 	sw	$s0,0x18($sp)
-/*    34040:	3c01800a */ 	lui	$at,%hi(var8009c340)
-/*    34044:	a020c340 */ 	sb	$zero,%lo(var8009c340)($at)
-/*    34048:	3c01800a */ 	lui	$at,%hi(var8009c340+0x1)
-/*    3404c:	a020c341 */ 	sb	$zero,%lo(var8009c340+0x1)($at)
-/*    34050:	3c01800a */ 	lui	$at,%hi(var8009c340+0x2)
-/*    34054:	a020c342 */ 	sb	$zero,%lo(var8009c340+0x2)($at)
-/*    34058:	93b0002b */ 	lbu	$s0,0x2b($sp)
-/*    3405c:	24010001 */ 	addiu	$at,$zero,0x1
-/*    34060:	12010009 */ 	beq	$s0,$at,.L00034088
-/*    34064:	00000000 */ 	nop
-/*    34068:	24010003 */ 	addiu	$at,$zero,0x3
-/*    3406c:	1201000b */ 	beq	$s0,$at,.L0003409c
-/*    34070:	00000000 */ 	nop
-/*    34074:	24010004 */ 	addiu	$at,$zero,0x4
-/*    34078:	1201000d */ 	beq	$s0,$at,.L000340b0
-/*    3407c:	00000000 */ 	nop
-/*    34080:	10000010 */ 	b	.L000340c4
-/*    34084:	00000000 */ 	nop
-.L00034088:
-/*    34088:	240e0001 */ 	addiu	$t6,$zero,0x1
-/*    3408c:	3c01800a */ 	lui	$at,%hi(var8009c340+0x1)
-/*    34090:	a02ec341 */ 	sb	$t6,%lo(var8009c340+0x1)($at)
-/*    34094:	1000000b */ 	b	.L000340c4
-/*    34098:	00000000 */ 	nop
-.L0003409c:
-/*    3409c:	240f0001 */ 	addiu	$t7,$zero,0x1
-/*    340a0:	3c01800a */ 	lui	$at,%hi(var8009c340+0x2)
-/*    340a4:	a02fc342 */ 	sb	$t7,%lo(var8009c340+0x2)($at)
-/*    340a8:	10000006 */ 	b	.L000340c4
-/*    340ac:	00000000 */ 	nop
-.L000340b0:
-/*    340b0:	24180001 */ 	addiu	$t8,$zero,0x1
-/*    340b4:	3c01800a */ 	lui	$at,%hi(var8009c340)
-/*    340b8:	a038c340 */ 	sb	$t8,%lo(var8009c340)($at)
-/*    340bc:	10000001 */ 	b	.L000340c4
-/*    340c0:	00000000 */ 	nop
-.L000340c4:
-/*    340c4:	afa00024 */ 	sw	$zero,0x24($sp)
-.L000340c8:
-/*    340c8:	8fa40024 */ 	lw	$a0,0x24($sp)
-/*    340cc:	0c00d041 */ 	jal	speaker00034104
-/*    340d0:	00002825 */ 	or	$a1,$zero,$zero
-/*    340d4:	8fb90024 */ 	lw	$t9,0x24($sp)
-/*    340d8:	27280001 */ 	addiu	$t0,$t9,0x1
-/*    340dc:	29010002 */ 	slti	$at,$t0,0x2
-/*    340e0:	1420fff9 */ 	bnez	$at,.L000340c8
-/*    340e4:	afa80024 */ 	sw	$t0,0x24($sp)
-/*    340e8:	10000001 */ 	b	.L000340f0
-/*    340ec:	00000000 */ 	nop
-.L000340f0:
-/*    340f0:	8fbf001c */ 	lw	$ra,0x1c($sp)
-/*    340f4:	8fb00018 */ 	lw	$s0,0x18($sp)
-/*    340f8:	27bd0028 */ 	addiu	$sp,$sp,0x28
-/*    340fc:	03e00008 */ 	jr	$ra
-/*    34100:	00000000 */ 	nop
-);
+void speakersSetMode(u8 mode)
+{
+	s32 i;
+
+	var8009c340.surround = 0;
+	var8009c340.mono = 0;
+	var8009c340.headphone = 0;
+
+	switch (mode) {
+	case SPEAKERMODE_MONO:
+		var8009c340.mono = 1;
+		break;
+	case SPEAKERMODE_HEADPHONE:
+		var8009c340.headphone = 1;
+		break;
+	case SPEAKERMODE_SURROUND:
+		var8009c340.surround = 1;
+		break;
+	}
+
+	for (i = 0; i < 2; i++) {
+		speaker00034104(i, 0);
+	}
+}
 
 GLOBAL_ASM(
 glabel speaker00034104