diff --git a/public/engine/IEngineSound.h b/public/engine/IEngineSound.h
index 784487f8..f5233644 100644
--- a/public/engine/IEngineSound.h
+++ b/public/engine/IEngineSound.h
@@ -73,15 +73,15 @@ public:
 	// NOTE: setting iEntIndex to -1 will cause the sound to be emitted from the local
 	// player (client-side only)
 	virtual int EmitSound( IRecipientFilter& filter, int iEntIndex, int iChannel, const char *pSoundEntry, unsigned int nSoundEntryHash, const char *pSample, 
-		float flVolume, float flAttenuation, int iUnknown3, int iFlags = 0, int iPitch = PITCH_NORM, 
+		float flVolume, float flAttenuation, int nSeed, int iFlags = 0, int iPitch = PITCH_NORM, 
 		const Vector *pOrigin = NULL, const Vector *pDirection = NULL, CUtlVector< Vector >* pUtlVecOrigins = NULL, bool bUpdatePositions = true, float soundtime = 0.0f, int speakerentity = -1 ) = 0;
 
 	virtual int EmitSound( IRecipientFilter& filter, int iEntIndex, int iChannel, const char *pSoundEntry, unsigned int nSoundEntryHash, const char *pSample, 
-		float flVolume, soundlevel_t iSoundlevel, int iUnknown3, int iFlags = 0, int iPitch = PITCH_NORM, 
+		float flVolume, soundlevel_t iSoundlevel, int nSeed, int iFlags = 0, int iPitch = PITCH_NORM, 
 		const Vector *pOrigin = NULL, const Vector *pDirection = NULL, CUtlVector< Vector >* pUtlVecOrigins = NULL, bool bUpdatePositions = true, float soundtime = 0.0f, int speakerentity = -1 ) = 0;
 
 	virtual void EmitSentenceByIndex( IRecipientFilter& filter, int iEntIndex, int iChannel, int iSentenceIndex, 
-		float flVolume, soundlevel_t iSoundlevel, int iUnknown, int iFlags = 0, int iPitch = PITCH_NORM,
+		float flVolume, soundlevel_t iSoundlevel, int nSeed, int iFlags = 0, int iPitch = PITCH_NORM,
 		const Vector *pOrigin = NULL, const Vector *pDirection = NULL, CUtlVector< Vector >* pUtlVecOrigins = NULL, bool bUpdatePositions = true, float soundtime = 0.0f, int speakerentity = -1 ) = 0;
 
 	virtual void StopSound( int iEntIndex, int iChannel, const char *pSample, unsigned int nSoundEntryHash ) = 0;
@@ -97,7 +97,7 @@ public:
 	
 	// emit an "ambient" sound that isn't spatialized
 	// only available on the client, assert on server
-	virtual void EmitAmbientSound( const char *pSample, float flVolume, int iPitch = PITCH_NORM, int flags = 0, float soundtime = 0.0f ) = 0;
+	virtual int EmitAmbientSound( const char *pSample, float flVolume, int iPitch = PITCH_NORM, int flags = 0, float soundtime = 0.0f ) = 0;
 
 
 //	virtual EntChannel_t	CreateEntChannel() = 0;
@@ -107,7 +107,7 @@ public:
 	// Client .dll only functions
 	virtual int		GetGuidForLastSoundEmitted() = 0;
 	virtual bool	IsSoundStillPlaying( int guid ) = 0;
-	virtual void	StopSoundByGuid( int guid ) = 0;
+	virtual void	StopSoundByGuid( int guid, bool bForceSync ) = 0;
 	// Set's master volume (0.0->1.0)
 	virtual void	SetVolumeByGuid( int guid, float fvol ) = 0;