diff --git a/src/sound/s_sound.cpp b/src/sound/s_sound.cpp
index 08417277f..b5bb73234 100644
--- a/src/sound/s_sound.cpp
+++ b/src/sound/s_sound.cpp
@@ -86,15 +86,6 @@
 
 // MACROS ------------------------------------------------------------------
 
-#ifdef NeXT
-// NeXT doesn't need a binary flag in open call
-#define O_BINARY 0
-#endif
-
-#ifndef O_BINARY
-#define O_BINARY 0
-#endif
-
 #define NORM_PITCH				128
 #define NORM_PRIORITY			64
 #define NORM_SEP				0
diff --git a/src/sound/s_sound.h b/src/sound/s_sound.h
index a4ef2a335..cf7b52900 100644
--- a/src/sound/s_sound.h
+++ b/src/sound/s_sound.h
@@ -36,178 +36,11 @@ class FScanner;
 class FSerializer;
 struct FLevelLocals;
 
-//
-// SoundFX struct.
-//
-struct sfxinfo_t
-{
-	// Next field is for use by the system sound interface.
-	// A non-null data means the sound has been loaded.
-	SoundHandle	data;
-    // Also for the sound interface. Used for 3D positional
-    // sounds, may be the same as data.
-    SoundHandle data3d;
-
-	FString		name;					// [RH] Sound name defined in SNDINFO
-	int 		lumpnum;				// lump number of sfx
-
-	unsigned int next, index;			// [RH] For hashing
-	float		Volume;
-
-	uint8_t		PitchMask;
-	int16_t		NearLimit;				// 0 means unlimited
-	float		LimitRange;				// Range for sound limiting (squared for faster computations)
-
-	unsigned		bRandomHeader:1;
-	unsigned		bPlayerReserve:1;
-	unsigned		bLoadRAW:1;
-	unsigned		bPlayerCompat:1;
-	unsigned		b16bit:1;
-	unsigned		bUsed:1;
-	unsigned		bSingular:1;
-	unsigned		bTentative:1;
-	unsigned		bPlayerSilent:1;		// This player sound is intentionally silent.
-
-	int		RawRate;				// Sample rate to use when bLoadRAW is true
-
-	int			LoopStart;				// -1 means no specific loop defined
-
-	unsigned int link;
-	enum { NO_LINK = 0xffffffff };
-
-	FRolloffInfo	Rolloff;
-	float		Attenuation;			// Multiplies the attenuation passed to S_Sound.
-
-	void		MarkUsed();				// Marks this sound as used.
-};
-
-// Rolloff types
-enum
-{
-	ROLLOFF_Doom,		// Linear rolloff with a logarithmic volume scale
-	ROLLOFF_Linear,		// Linear rolloff with a linear volume scale
-	ROLLOFF_Log,		// Logarithmic rolloff (standard hardware type)
-	ROLLOFF_Custom		// Lookup volume from SNDCURVE
-};
-
-int S_FindSound (const char *logicalname);
-
-// the complete set of sound effects
-extern TArray<sfxinfo_t> S_sfx;
-
-// An index into the S_sfx[] array.
-class FSoundID
-{
-public:
-	FSoundID() = default;
-
-	FSoundID(int id)
-	{
-		ID = id;
-	}
-	FSoundID(const char *name)
-	{
-		ID = S_FindSound(name);
-	}
-	FSoundID(const FString &name)
-	{
-		ID = S_FindSound(name.GetChars());
-	}
-	FSoundID(const FSoundID &other) = default;
-	FSoundID &operator=(const FSoundID &other) = default;
-	FSoundID &operator=(const char *name)
-	{
-		ID = S_FindSound(name);
-		return *this;
-	}
-	FSoundID &operator=(const FString &name)
-	{
-		ID = S_FindSound(name.GetChars());
-		return *this;
-	}
-	bool operator !=(FSoundID other) const
-	{
-		return ID != other.ID;
-	}
-	bool operator !=(int other) const
-	{
-		return ID != other;
-	}
-	operator int() const
-	{
-		return ID;
-	}
-	operator FString() const
-	{
-		return ID ? S_sfx[ID].name : "";
-	}
-	operator const char *() const
-	{
-		return ID ? S_sfx[ID].name.GetChars() : NULL;
-	}
-	void MarkUsed() const
-	{
-		S_sfx[ID].MarkUsed();
-	}
-private:
-	int ID;
-protected:
-	enum EDummy { NoInit };
-	FSoundID(EDummy) {}
-};
-
-class FSoundIDNoInit : public FSoundID
-{
-public:
-	FSoundIDNoInit() : FSoundID(NoInit) {}
-	using FSoundID::operator=;
-};
-
-extern FRolloffInfo S_Rolloff;
-extern TArray<uint8_t> S_SoundCurve;
-
+#include "s_soundinternal.h"
 
 // Information about one playing sound.
 struct sector_t;
 struct FPolyObj;
-struct FSoundChan : public FISoundChannel
-{
-	FSoundChan	*NextChan;	// Next channel in this list.
-	FSoundChan **PrevChan;	// Previous channel in this list.
-	FSoundID	SoundID;	// Sound ID of playing sound.
-	FSoundID	OrgID;		// Sound ID of sound used to start this channel.
-	float		Volume;
-	int16_t		Pitch;		// Pitch variation.
-	uint8_t		EntChannel;	// Actor's sound channel.
-	int8_t		Priority;
-	int16_t		NearLimit;
-	uint8_t		SourceType;
-	float		LimitRange;
-	union
-	{
-		AActor			*Actor;		// Used for position and velocity.
-		const sector_t	*Sector;	// Sector for area sounds.
-		const FPolyObj	*Poly;		// Polyobject sound source.
-		float			 Point[3];	// Sound is not attached to any source.
-	};
-};
-
-extern FSoundChan *Channels;
-
-void S_ReturnChannel(FSoundChan *chan);
-void S_EvictAllChannels();
-
-void S_StopChannel(FSoundChan *chan);
-void S_LinkChannel(FSoundChan *chan, FSoundChan **head);
-void S_UnlinkChannel(FSoundChan *chan);
-
-// Initializes sound stuff, including volume
-// Sets channels, SFX and music volume,
-//	allocates channel buffer, sets S_sfx lookup.
-//
-void S_Init ();
-void S_InitData ();
-void S_Shutdown ();
 
 // Per level startup code.
 // Kills playing sounds at start of level and starts new music.
@@ -217,9 +50,6 @@ void S_Start ();
 // Called after a level is loaded. Ensures that most sounds are loaded.
 void S_PrecacheLevel (FLevelLocals *l);
 
-// Loads a sound, including any random sounds it might reference.
-void S_CacheSound (sfxinfo_t *sfx);
-
 // Start sound for thing at <ent>
 void S_Sound (int channel, FSoundID sfxid, float volume, float attenuation);
 void S_Sound (AActor *ent, int channel, FSoundID sfxid, float volume, float attenuation);
@@ -235,61 +65,10 @@ void S_SoundPitchActor (AActor *ent, int channel, FSoundID sfxid, float volume,
 void S_PlaySound(AActor *a, int chan, FSoundID sid, float vol, float atten, bool local);
 void S_PlaySoundPitch(AActor *a, int chan, FSoundID sid, float vol, float atten, bool local, float pitch);
 
-// sound channels
-// channel 0 never willingly overrides
-// other channels (1-7) always override a playing sound on that channel
-//
-// CHAN_AUTO searches down from channel 7 until it finds a channel not in use
-// CHAN_WEAPON is for weapons
-// CHAN_VOICE is for oof, sight, or other voice sounds
-// CHAN_ITEM is for small things and item pickup
-// CHAN_BODY is for generic body sounds
-// CHAN_PICKUP can optionally be set as a local sound only for "compatibility"
-
-#define CHAN_AUTO				0
-#define CHAN_WEAPON				1
-#define CHAN_VOICE				2
-#define CHAN_ITEM				3
-#define CHAN_BODY				4
-
-// Channel alias for sector sounds. These define how listener height is
-// used when calculating 3D sound volume.
-#define CHAN_FLOOR				1	// Sound comes from the floor.
-#define CHAN_CEILING			2	// Sound comes from the ceiling.
-#define CHAN_FULLHEIGHT			3	// Sound comes entire height of the sector.
-#define CHAN_INTERIOR			4	// Sound comes height between floor and ceiling.
-
-// modifier flags
-#define CHAN_LISTENERZ			8
-#define CHAN_MAYBE_LOCAL		16
-#define CHAN_UI					32	// Do not record sound in savegames.
-#define CHAN_NOPAUSE			64	// Do not pause this sound in menus.
-#define CHAN_AREA				128	// Sound plays from all around. Only valid with sector sounds.
-#define CHAN_LOOP				256
-
-#define CHAN_PICKUP				(CHAN_ITEM|CHAN_MAYBE_LOCAL)
-
-#define CHAN_IS3D				1	// internal: Sound is 3D.
-#define CHAN_EVICTED			2	// internal: Sound was evicted.
-#define CHAN_FORGETTABLE		4	// internal: Forget channel data when sound stops.
-#define CHAN_JUSTSTARTED		512	// internal: Sound has not been updated yet.
-#define CHAN_ABSTIME			1024// internal: Start time is absolute and does not depend on current time.
-#define CHAN_VIRTUAL			2048// internal: Channel is currently virtual
-#define CHAN_NOSTOP				4096// only for A_PlaySound. Does not start if channel is playing something.
-
-// sound attenuation values
-#define ATTN_NONE				0.f	// full volume the entire level
-#define ATTN_NORM				1.f
-#define ATTN_IDLE				1.001f
-#define ATTN_STATIC				3.f	// diminish very rapidly with distance
-
 struct FSoundLoadBuffer;
 int S_PickReplacement (int refid);
 void S_CacheRandomSound (sfxinfo_t *sfx);
 
-// Checks if a copy of this sound is already playing.
-bool S_CheckSingular (int sound_id);
-
 // Stops a sound emanating from one of an emitter's channels.
 void S_StopSound (AActor *ent, int channel);
 void S_StopSound (const sector_t *sec, int channel);
@@ -321,11 +100,6 @@ void S_RelinkSound (AActor *from, AActor *to);
 // Stores/retrieves playing channel information in an archive.
 void S_SerializeSounds(FSerializer &arc);
 
-// Stop and resume music, during game PAUSE.
-void S_PauseSound (bool notmusic, bool notsfx);
-void S_ResumeSound (bool notsfx);
-void S_SetSoundPaused (int state);
-
 //
 // Updates music & sounds
 //
@@ -336,8 +110,6 @@ void S_RestoreEvictedChannels();
 // [RH] S_sfx "maintenance" routines
 void S_ClearSoundData();
 void S_ParseSndInfo (bool redefine);
-void S_ParseReverbDef ();
-void S_UnloadReverbDef ();
 
 void S_HashSounds ();
 int S_FindSoundNoHash (const char *logicalname);
@@ -364,14 +136,4 @@ void A_PlaySound(AActor *self, int soundid, int channel, double volume, int loop
 //		Modelled after Hexen's noise cheat.
 void S_NoiseDebug ();
 
-extern ReverbContainer *Environments;
-extern ReverbContainer *DefaultEnvironments[26];
-
-void S_SetEnvironment (const ReverbContainer *settings);
-ReverbContainer *S_FindEnvironment (const char *name);
-ReverbContainer *S_FindEnvironment (int id);
-void S_AddEnvironment (ReverbContainer *settings);
-void S_UnloadAllSounds();
-void S_SoundReset();
-	
 #endif
diff --git a/src/sound/s_soundinternal.h b/src/sound/s_soundinternal.h
new file mode 100644
index 000000000..0c2dd6801
--- /dev/null
+++ b/src/sound/s_soundinternal.h
@@ -0,0 +1,268 @@
+#pragma once
+
+#include "i_soundinternal.h"
+
+
+//
+// SoundFX struct.
+//
+struct sfxinfo_t
+{
+	// Next field is for use by the system sound interface.
+	// A non-null data means the sound has been loaded.
+	SoundHandle	data;
+    // Also for the sound interface. Used for 3D positional
+    // sounds, may be the same as data.
+    SoundHandle data3d;
+
+	FString		name;					// [RH] Sound name defined in SNDINFO
+	int 		lumpnum;				// lump number of sfx
+
+	unsigned int next, index;			// [RH] For hashing
+	float		Volume;
+
+	uint8_t		ResourceId;				// Resource ID as implemented by Blood. Not used by Doom but added for completeness.
+	uint8_t		PitchMask;
+	int16_t		NearLimit;				// 0 means unlimited
+	float		LimitRange;				// Range for sound limiting (squared for faster computations)
+
+	unsigned		bRandomHeader:1;
+	unsigned		bPlayerReserve:1;
+	unsigned		bLoadRAW:1;
+	unsigned		bPlayerCompat:1;
+	unsigned		b16bit:1;
+	unsigned		bUsed:1;
+	unsigned		bSingular:1;
+	unsigned		bTentative:1;
+	unsigned		bPlayerSilent:1;		// This player sound is intentionally silent.
+
+	int		RawRate;				// Sample rate to use when bLoadRAW is true
+
+	int			LoopStart;				// -1 means no specific loop defined
+
+	unsigned int link;
+	enum { NO_LINK = 0xffffffff };
+
+	FRolloffInfo	Rolloff;
+	float		Attenuation;			// Multiplies the attenuation passed to S_Sound.
+
+	void		MarkUsed();				// Marks this sound as used.
+};
+
+// Rolloff types
+enum
+{
+	ROLLOFF_Doom,		// Linear rolloff with a logarithmic volume scale
+	ROLLOFF_Linear,		// Linear rolloff with a linear volume scale
+	ROLLOFF_Log,		// Logarithmic rolloff (standard hardware type)
+	ROLLOFF_Custom		// Lookup volume from SNDCURVE
+};
+
+int S_FindSound(const char *logicalname);
+int S_FindSoundByResID(int snd_id);
+
+// the complete set of sound effects
+extern TArray<sfxinfo_t> S_sfx;
+
+// An index into the S_sfx[] array.
+class FSoundID
+{
+public:
+	FSoundID() = default;
+	
+	static FSoundID byResId(int ndx)
+	{
+		return FSoundID(S_FindSoundByResID(ndx)); 
+	}
+	FSoundID(int id)
+	{
+		ID = id;
+	}
+	FSoundID(const char *name)
+	{
+		ID = S_FindSound(name);
+	}
+	FSoundID(const FString &name)
+	{
+		ID = S_FindSound(name.GetChars());
+	}
+	FSoundID(const FSoundID &other) = default;
+	FSoundID &operator=(const FSoundID &other) = default;
+	FSoundID &operator=(const char *name)
+	{
+		ID = S_FindSound(name);
+		return *this;
+	}
+	FSoundID &operator=(const FString &name)
+	{
+		ID = S_FindSound(name.GetChars());
+		return *this;
+	}
+	bool operator !=(FSoundID other) const
+	{
+		return ID != other.ID;
+	}
+	bool operator !=(int other) const
+	{
+		return ID != other;
+	}
+	operator int() const
+	{
+		return ID;
+	}
+	operator FString() const
+	{
+		return ID ? S_sfx[ID].name : "";
+	}
+	operator const char *() const
+	{
+		return ID ? S_sfx[ID].name.GetChars() : NULL;
+	}
+	void MarkUsed() const
+	{
+		S_sfx[ID].MarkUsed();
+	}
+private:
+	int ID;
+protected:
+	enum EDummy { NoInit };
+	FSoundID(EDummy) {}
+};
+ 
+ class FSoundIDNoInit : public FSoundID
+{
+public:
+	FSoundIDNoInit() : FSoundID(NoInit) {}
+	using FSoundID::operator=;
+};
+
+extern FRolloffInfo S_Rolloff;
+extern TArray<uint8_t> S_SoundCurve;
+
+
+typedef FVector3(*GetSourceOrigin)(const float *listenerpos, const void *source);
+
+class AActor;
+struct sector_t;
+struct FPolyObj;
+struct FSoundChan : public FISoundChannel
+{
+	FSoundChan	*NextChan;	// Next channel in this list.
+	FSoundChan **PrevChan;	// Previous channel in this list.
+	FSoundID	SoundID;	// Sound ID of playing sound.
+	FSoundID	OrgID;		// Sound ID of sound used to start this channel.
+	float		Volume;
+	int16_t		Pitch;		// Pitch variation.
+	uint8_t		EntChannel;	// Actor's sound channel.
+	int8_t		Priority;
+	int16_t		NearLimit;
+	uint8_t		SourceType;
+	float		LimitRange;
+	union
+	{
+		AActor			*Actor;		// Used for position and velocity.
+		const sector_t	*Sector;	// Sector for area sounds.
+		const FPolyObj	*Poly;		// Polyobject sound source.
+		struct
+		{
+			void *Source;
+			GetSourceOrigin getOrigin;
+		};
+		float Point[3];	// Sound is not attached to any source.
+	};
+};
+
+extern FSoundChan *Channels;
+
+void S_ReturnChannel(FSoundChan *chan);
+void S_EvictAllChannels();
+
+void S_StopChannel(FSoundChan *chan);
+void S_LinkChannel(FSoundChan *chan, FSoundChan **head);
+void S_UnlinkChannel(FSoundChan *chan);
+
+// Initializes sound stuff, including volume
+// Sets channels, SFX and music volume,
+//	allocates channel buffer, sets S_sfx lookup.
+//
+void S_Init ();
+void S_InitData ();
+void S_Shutdown ();
+
+// Loads a sound, including any random sounds it might reference.
+void S_CacheSound (sfxinfo_t *sfx);
+
+// sound channels
+// channel 0 never willingly overrides
+// other channels (1-7) always override a playing sound on that channel
+//
+// CHAN_AUTO searches down from channel 7 until it finds a channel not in use
+// CHAN_WEAPON is for weapons
+// CHAN_VOICE is for oof, sight, or other voice sounds
+// CHAN_ITEM is for small things and item pickup
+// CHAN_BODY is for generic body sounds
+// CHAN_PICKUP can optionally be set as a local sound only for "compatibility"
+
+enum
+{
+	CHAN_AUTO				= 0,
+	CHAN_WEAPON				= 1,
+	CHAN_VOICE				= 2,
+	CHAN_ITEM				= 3,
+	CHAN_BODY				= 4,
+	CHAN_5					= 5,
+	CHAN_6					= 6,
+	CHAN_7					= 7,
+
+	// Channel alias for sector sounds. These define how listener height is
+	// used when calculating 3D sound volume.
+	CHAN_FLOOR				= 1,	// Sound comes from the floor.
+	CHAN_CEILING			= 2,	// Sound comes from the ceiling.
+	CHAN_FULLHEIGHT			= 3,	// Sound comes entire height of the sector.
+	CHAN_INTERIOR			= 4,	// Sound comes height between floor and ceiling.
+
+	// modifier flags
+	CHAN_LISTENERZ			= 8,
+	CHAN_MAYBE_LOCAL		= 16,
+	CHAN_UI					= 32,	// Do not record sound in savegames.
+	CHAN_NOPAUSE			= 64,	// Do not pause this sound in menus.
+	CHAN_AREA				= 128,	// Sound plays from all around. Only valid with sector sounds.
+	CHAN_LOOP				= 256,
+
+	CHAN_PICKUP				= (CHAN_ITEM|CHAN_MAYBE_LOCAL),
+
+	CHAN_IS3D				= 1,		// internal: Sound is 3D.
+	CHAN_EVICTED			= 2,		// internal: Sound was evicted.
+	CHAN_FORGETTABLE		= 4,		// internal: Forget channel data when sound stops.
+	CHAN_JUSTSTARTED		= 512,	// internal: Sound has not been updated yet.
+	CHAN_ABSTIME			= 1024,	// internal: Start time is absolute and does not depend on current time.
+	CHAN_VIRTUAL			= 2048,	// internal: Channel is currently virtual
+	CHAN_NOSTOP				= 4096,	// only for A_PlaySound. Does not start if channel is playing something.
+};
+
+// sound attenuation values
+#define ATTN_NONE				0.f	// full volume the entire level
+#define ATTN_NORM				1.f
+#define ATTN_IDLE				1.001f
+#define ATTN_STATIC				3.f	// diminish very rapidly with distance
+
+// Checks if a copy of this sound is already playing.
+bool S_CheckSingular (int sound_id);
+
+// Stop and resume music, during game PAUSE.
+void S_PauseSound (bool notmusic, bool notsfx);
+void S_ResumeSound (bool notsfx);
+void S_SetSoundPaused (int state);
+
+extern ReverbContainer *Environments;
+extern ReverbContainer *DefaultEnvironments[26];
+
+void S_ParseReverbDef ();
+void S_UnloadReverbDef ();
+void S_SetEnvironment (const ReverbContainer *settings);
+ReverbContainer *S_FindEnvironment (const char *name);
+ReverbContainer *S_FindEnvironment (int id);
+void S_AddEnvironment (ReverbContainer *settings);
+void S_UnloadAllSounds();
+void S_SoundReset();
+