diff --git a/sound.c b/sound.c
--- a/sound.c
+++ b/sound.c
@@ -1,33 +1,13 @@
 #include "stdafx.h"
 #include "ttd.h"
 #include "map.h"
+#include "mixer.h"
 #include "sound.h"
 #include "vehicle.h"
 #include "window.h"
 #include "viewport.h"
 #include "fileio.h"
 
-typedef struct MixerChannel {
-	// Mixer
-	Mixer *mx;
-	bool active;
-
-	// pointer to allocated buffer memory
-	int8 *memory;
-
-	// current position in memory
-	uint32 pos;
-	uint32 frac_pos;
-	uint32 frac_speed;
-	uint32 samples_left;
-
-	// Mixing volume
-	uint volume_left;
-	uint volume_right;
-
-	uint flags;
-} MixerChannel;
-
 typedef struct FileEntry {
 	uint32 file_offset;
 	uint32 file_size;
@@ -36,150 +16,29 @@ typedef struct FileEntry {
 	uint8 channels;
 } FileEntry;
 
-struct Mixer {
-	uint32 play_rate;
-	FileEntry *files;
-	uint32 file_count;
-	MixerChannel channels[8];
-};
-
-enum {
-	MX_AUTOFREE = 1,
-//	MX_8BIT = 2,
-//	MX_STEREO = 4,
-	MX_UNSIGNED = 8,
-};
+static uint _file_count;
+static FileEntry* _files;
 
 #define SOUND_SLOT 31
 
 
-static void mix_int8_to_int16(MixerChannel *sc, int16 *buffer, uint samples)
-{
-	int8 *b;
-	uint32 frac_pos;
-	uint32 frac_speed;
-	uint volume_left;
-	uint volume_right;
-
-	if (samples > sc->samples_left) samples = sc->samples_left;
-	sc->samples_left -= samples;
-	assert(samples > 0);
-
-	b = sc->memory + sc->pos;
-	frac_pos = sc->frac_pos;
-	frac_speed = sc->frac_speed;
-	volume_left = sc->volume_left;
-	volume_right = sc->volume_right;
-
-	if (frac_speed == 0x10000) {
-		// Special case when frac_speed is 0x10000
-		do {
-			buffer[0] += *b * volume_left >> 8;
-			buffer[1] += *b * volume_right >> 8;
-			b++;
-			buffer += 2;
-		} while (--samples > 0);
-	} else {
-		do {
-			buffer[0] += *b * volume_left >> 8;
-			buffer[1] += *b * volume_right >> 8;
-			buffer += 2;
-			frac_pos += frac_speed;
-			b += frac_pos >> 16;
-			frac_pos &= 0xffff;
-		} while (--samples > 0);
-	}
-
-	sc->frac_pos = frac_pos;
-	sc->pos = b - sc->memory;
-}
-
-static void MxCloseChannel(MixerChannel *mc)
-{
-	if (mc->flags & MX_AUTOFREE) free(mc->memory);
-	mc->memory = NULL;
-	mc->active = false;
-}
-
-void MxMixSamples(Mixer *mx, void *buffer, uint samples)
-{
-	MixerChannel *mc;
-
-	// Clear the buffer
-	memset(buffer, 0, sizeof(int16) * 2 * samples);
-
-	// Mix each channel
-	for (mc = mx->channels; mc != endof(mx->channels); mc++) {
-		if (mc->active) {
-			mix_int8_to_int16(mc, buffer, samples);
-			if (mc->samples_left == 0) MxCloseChannel(mc);
-		}
-	}
-
-	#if 0
-	{
-		static FILE *out = NULL;
-		if (out == NULL)
-			out = fopen("d:\\dump.raw", "wb");
-		fwrite(buffer, samples * 4, 1, out);
-	}
-	#endif
-}
-
-static MixerChannel *MxAllocateChannel(Mixer *mx)
-{
-	MixerChannel *mc;
-	for (mc = mx->channels; mc != endof(mx->channels); mc++)
-		if (mc->memory == NULL) {
-			mc->active = false;
-			mc->mx = mx;
-			return mc;
-		}
-	return NULL;
-}
-
-static void MxSetChannelRawSrc(MixerChannel *mc, int8 *mem, uint size, uint rate, uint flags)
-{
-	mc->memory = mem;
-	mc->flags = flags;
-	mc->frac_pos = 0;
-	mc->pos = 0;
-
-	mc->frac_speed = (rate << 16) / mc->mx->play_rate;
-
-	// adjust the magnitude to prevent overflow
-	while (size & 0xFFFF0000) {
-		size >>= 1;
-		rate = (rate >> 1) + 1;
-	}
-
-	mc->samples_left = size * mc->mx->play_rate / rate;
-}
-
-static void MxSetChannelVolume(MixerChannel *mc, uint left, uint right)
-{
-	mc->volume_left = left;
-	mc->volume_right = right;
-}
-
-static void MxOpenBankFile(Mixer *mx, const char *filename)
+static void OpenBankFile(const char *filename)
 {
 	uint count, i;
 	uint32 size, tag;
 	FileEntry *fe;
 
 	FioOpenFile(SOUND_SLOT, filename);
-	mx->file_count = count = FioReadDword() >> 3;
-	fe = mx->files = calloc(sizeof(FileEntry), count);
+	_file_count = count = FioReadDword() >> 3;
+	fe = _files = calloc(sizeof(FileEntry), count);
 
 	FioSeekTo(0, SEEK_SET);
 
-	for (i = 0; i != count; i++, fe++) {
-		fe->file_offset = FioReadDword();
-		fe->file_size = FioReadDword();
+	for (i = 0; i != count; i++) {
+		fe[i].file_offset = FioReadDword();
+		fe[i].file_size = FioReadDword();
 	}
 
-	fe = mx->files;
 	for (i = 0; i != count; i++, fe++) {
 		char name[255];
 
@@ -227,9 +86,9 @@ static void MxOpenBankFile(Mixer *mx, co
 	}
 }
 
-static bool MxSetBankSource(MixerChannel *mc, uint bank)
+static bool SetBankSource(MixerChannel *mc, uint bank)
 {
-	FileEntry *fe = &mc->mx->files[bank];
+	FileEntry *fe = &_files[bank];
 	int8 *mem;
 	uint i;
 
@@ -245,17 +104,14 @@ static bool MxSetBankSource(MixerChannel
 
 	assert(fe->bits_per_sample == 8 && fe->channels == 1 && fe->file_size != 0 && fe->rate != 0);
 
-	MxSetChannelRawSrc(mc, mem, fe->file_size, fe->rate, MX_AUTOFREE | MX_UNSIGNED);
+	MxSetChannelRawSrc(mc, mem, fe->file_size, fe->rate, MX_AUTOFREE);
 
 	return true;
 }
 
-bool MxInitialize(uint rate, const char *filename)
+bool SoundInitialize(const char *filename)
 {
-	static Mixer mx;
-	_mixer = &mx;
-	mx.play_rate = rate;
-	MxOpenBankFile(&mx, filename);
+	OpenBankFile(filename);
 	return true;
 }
 
@@ -266,9 +122,9 @@ static void StartSound(uint sound, uint 
 		MixerChannel *mc = MxAllocateChannel(_mixer);
 		if (mc == NULL)
 			return;
-		if (MxSetBankSource(mc, sound)) {
+		if (SetBankSource(mc, sound)) {
 			MxSetChannelVolume(mc, volume << 8, volume << 8);
-			mc->active = true;
+			MxActivate(mc);
 		}
 	}
 }