diff --git a/src/modules/graphic/ssggraph/CarSoundData.cpp b/src/modules/graphic/ssggraph/CarSoundData.cpp
index 9b4d8dc3..8ba572e9 100644
--- a/src/modules/graphic/ssggraph/CarSoundData.cpp
+++ b/src/modules/graphic/ssggraph/CarSoundData.cpp
@@ -60,6 +60,7 @@ CarSoundData::CarSoundData(int id, SoundInterface* sound_interface)
     
     attenuation = 0.0f;
 }
+
 void CarSoundData::setEngineSound (Sound* engine_sound, float rpm_scale)
 {
     this->engine_sound = engine_sound;
@@ -76,6 +77,52 @@ void CarSoundData::setTurboParameters (bool turbo_on, float turbo_rpm, float tur
         fprintf (stderr, "warning: turbo lag %f <= 0\n", turbo_lag);
     }
 }
+
+Sound* CarSoundData::getEngineSound () const
+{
+	return engine_sound;
+}
+
+void CarSoundData::copyEngPri (SoundPri& epri) const
+{
+	epri = eng_pri;
+}
+
+void CarSoundData::setCarPosition (sgVec3 p)
+{
+	for (int i=0; i<3; i++) {
+		position[i] = p[i];
+	}
+}
+
+void CarSoundData::setCarSpeed (sgVec3 u)
+{
+	for (int i=0; i<3; i++) {
+		speed[i] = u[i];
+	}
+}
+
+void CarSoundData::getCarPosition (sgVec3 p) const
+{
+	for (int i=0; i<3; i++) {
+		p[i] = position[i];
+	}
+}
+
+void CarSoundData::getCarSpeed (sgVec3 u) const
+{
+	for (int i=0; i<3; i++) {
+		u[i] = speed[i];
+	}
+}
+
+void CarSoundData::setListenerPosition (sgVec3 p)
+{
+	for (int i=0; i<3; i++) {
+		listener_position[i] = p[i];
+	}
+}
+
 void CarSoundData::update (tCarElt* car)
 {
     assert (car->index == eng_pri.id);
@@ -345,9 +392,9 @@ void CarSoundData::calculateCollisionSound (tCarElt* car)
         return;
     }
         
-    int collision  = car->priv.collision;
+    const int collision = car->priv.collision;
     if (collision) {
-        if (collision & 1) {
+        if (collision & SEM_COLLISION) {
             skid_metal.a = (tdble)(car->_speed_xy * 0.01);
             skid_metal.f = (tdble)(.5+0.5*skid_metal.a);
             drag_collision.f = skid_metal.f;
@@ -355,23 +402,23 @@ void CarSoundData::calculateCollisionSound (tCarElt* car)
             skid_metal.a = 0;
         }
 
-        if ((collision & 16 )) {
+        if (collision & SEM_COLLISION_Z_CRASH) {
             bottom_crash = true;
         }
 
-        if ((collision & 8 )) {
+        if (collision & SEM_COLLISION_Z) {
             bang = true;
         }
 
-        if (((collision & 1) ==0) ||
-            ((collision & 2)
-             &&(skid_metal.a >drag_collision.a))) {
+		// No crash sound if a dragging sound is already playing.
+        if (!(collision & SEM_COLLISION)
+			|| ((collision & SEM_COLLISION_XYSCENE) && skid_metal.a > drag_collision.a)) {
             crash = true;
         }
     }
 
     drag_collision.a = 0.9f*drag_collision.a + skid_metal.a;
-    if (drag_collision.a>1.0f) {
+    if (drag_collision.a > 1.0f) {
         drag_collision.a = 1.0f;
     }
     skid_metal.a = drag_collision.a;
diff --git a/src/modules/graphic/ssggraph/CarSoundData.h b/src/modules/graphic/ssggraph/CarSoundData.h
index 9a9d6865..d71fddda 100644
--- a/src/modules/graphic/ssggraph/CarSoundData.h
+++ b/src/modules/graphic/ssggraph/CarSoundData.h
@@ -28,8 +28,10 @@ typedef struct WheelSoundData_
 } WheelSoundData;
 
 /// Manages the source sound of each individual car.
-class CarSoundData {
+class CarSoundData
+{
 protected:
+	
 	sgVec3 listener_position;
 	sgVec3 position;
 	sgVec3 speed;
@@ -41,7 +43,9 @@ protected:
 	void calculateTyreSound (tCarElt* car);
 	void calculateGearChangeSound (tCarElt* car);
 	void calculateCollisionSound (tCarElt* car);
+
 public:
+	
 	SoundPri eng_pri;
 	WheelSoundData wheel[4];
 	float attenuation; ///< global distance attenuation
@@ -62,46 +66,24 @@ public:
 	QSoundChar skid_metal;
 	int prev_gear;
 
-	CarSoundData (int id, SoundInterface* sound_interface);
-	void setEngineSound (Sound* engine_sound, float rpm_scale);
-	void setTurboParameters (bool turbo_on, float turbo_rpm, float turbo_lag);
-	Sound* getEngineSound () {return engine_sound;}
-	void copyEngPri (SoundPri& epri) 	{epri = eng_pri;}
-	void setCarPosition (sgVec3 p)
-	{
-		for (int i=0; i<3; i++) {
-			position[i] = p[i];
-		}
-	}
-	void setCarSpeed (sgVec3 u)
-	{
-		for (int i=0; i<3; i++) {
-			speed[i] = u[i];
-		}
-	}
-	void getCarPosition (sgVec3 p)
-	{
-		for (int i=0; i<3; i++) {
-			p[i] = position[i];
-		}
-	}
-	void getCarSpeed (sgVec3 u)
-	{
-		for (int i=0; i<3; i++) {
-			u[i] = speed[i];
-		}
-	}
-	void setListenerPosition (sgVec3 p)
-	{
-		for (int i=0; i<3; i++) {
-			listener_position[i] = p[i];
-		}
-	}
-	void update (tCarElt* car);
 	bool gear_changing;
 	bool bottom_crash;
 	bool bang;
 	bool crash;
+
+public:
+	
+	CarSoundData (int id, SoundInterface* sound_interface);
+	void setEngineSound (Sound* engine_sound, float rpm_scale);
+	void setTurboParameters (bool turbo_on, float turbo_rpm, float turbo_lag);
+	Sound* getEngineSound () const;
+	void copyEngPri (SoundPri& epri) const;
+	void setCarPosition (sgVec3 p);
+	void setCarSpeed (sgVec3 u);
+	void getCarPosition (sgVec3 p) const;
+	void getCarSpeed (sgVec3 u) const;
+	void setListenerPosition (sgVec3 p);
+	void update (tCarElt* car);
 };
 
 #endif /* CAR_SOUND_DATA_H */
diff --git a/src/modules/graphic/ssggraph/OpenalSound.cpp b/src/modules/graphic/ssggraph/OpenalSound.cpp
index 0c21c984..6528a3eb 100644
--- a/src/modules/graphic/ssggraph/OpenalSound.cpp
+++ b/src/modules/graphic/ssggraph/OpenalSound.cpp
@@ -27,14 +27,9 @@
 
 OpenalSound::OpenalSound(const char* filename, OpenalSoundInterface* sitf,
 						 int flags, bool loop, bool static_pool)
+: Sound(flags, loop)
 {
-
-	this->loop = loop;
-	this->flags = flags;
 	this->static_pool = static_pool;
-	volume = 0.0f;
-	pitch = 1.0f;
-	lowpass = 1.0f;
 	poolindex = -1;
 	itf = sitf;
 
@@ -43,9 +38,6 @@ OpenalSound::OpenalSound(const char* filename, OpenalSoundInterface* sitf,
 	REFERENCE_DISTANCE = 5.0f;
 	ROLLOFF_FACTOR = 0.5f;
 
-	playing = false;
-	paused = false;
-
 	int i;
 	for (i = 0; i<3; i++) {
 		source_position[i] = 0.0f;
@@ -53,7 +45,8 @@ OpenalSound::OpenalSound(const char* filename, OpenalSoundInterface* sitf,
 		zeroes[i] = 0.0f;
 	}
 
-	GfOut("OpenAL : Creating %s source from %s\n", static_pool ? "static" : "dynamic", filename);
+	GfLogTrace("OpenAL : Creating %s source from %s\n",
+			   static_pool ? "static" : "dynamic", filename);
 
 	int error = alGetError();
 	if (error != AL_NO_ERROR) {
@@ -214,7 +207,6 @@ void OpenalSound::setLPFilter(float lp)
 	this->lowpass = lp;
 }
 
-
 void OpenalSound::setReferenceDistance(float dist)
 {
 	if (static_pool) {
@@ -229,7 +221,6 @@ void OpenalSound::setReferenceDistance(float dist)
 	}
 }
 
-
 void OpenalSound::setSource (sgVec3 p, sgVec3 u)
 {
 	for (int i=0; i<3; i++) {
@@ -238,7 +229,6 @@ void OpenalSound::setSource (sgVec3 p, sgVec3 u)
 	}
 }
 
-
 void OpenalSound::getSource(sgVec3 p, sgVec3 u)
 {
 	for (int i=0; i<3; i++) {
@@ -247,7 +237,6 @@ void OpenalSound::getSource(sgVec3 p, sgVec3 u)
 	}
 }
 
-
 void OpenalSound::play()
 {
 	start();
@@ -257,7 +246,7 @@ void OpenalSound::start()
 {
 	if (static_pool) {
 		if (is_enabled) {
-			if (playing==false) {
+			if (!playing) {
 				if (loop) {
 					playing = true;
 				}
@@ -281,7 +270,7 @@ void OpenalSound::start()
 			}
 
 			// play
-			if (playing==false) {
+			if (!playing) {
 				if (loop) {
 					playing = true;
 				}
@@ -291,12 +280,11 @@ void OpenalSound::start()
 	}
 }
 
-
 void OpenalSound::stop()
 {
 	if (static_pool) {
 		if (is_enabled) {
-			if (playing==true) {
+			if (playing) {
 				playing = false;
 				alSourceStop (source);
 			}
@@ -304,7 +292,7 @@ void OpenalSound::stop()
 	} else {
 		// Shared source.	
 		if (itf->getSourcePool()->releaseSource(this, &poolindex)) {
-			if (playing==true) {
+			if (playing) {
 				playing = false;
 				alSourceStop (source);
 			}
@@ -314,7 +302,7 @@ void OpenalSound::stop()
 
 void OpenalSound::resume()
 {
-	if (paused==true) {
+	if (paused) {
 		paused = false;
 	}
 }
@@ -322,14 +310,14 @@ void OpenalSound::resume()
 
 void OpenalSound::pause()
 {
-	if (paused==false) {
+	if (!paused) {
 		paused = true;
 	}
 }
 
 void OpenalSound::update ()
 {
-    ALfloat zero_velocity[3] = {0.0f, 0.0f, 0.0f};
+    static const ALfloat zero_velocity[3] = {0.0f, 0.0f, 0.0f};
 	if (static_pool) {
 		if (is_enabled) {
 			alSourcefv (source, AL_POSITION, source_position);
diff --git a/src/modules/graphic/ssggraph/OpenalSound.h b/src/modules/graphic/ssggraph/OpenalSound.h
index 4620f106..36fff331 100644
--- a/src/modules/graphic/ssggraph/OpenalSound.h
+++ b/src/modules/graphic/ssggraph/OpenalSound.h
@@ -42,7 +42,6 @@ protected:
 	ALfloat zeroes[3]; ///< just a vector of 0s
 	ALfloat back[6]; ///< direction of back
 	ALfloat front[6]; ///< direction of front 
-	bool playing, paused;
 	ALfloat MAX_DISTANCE; ///< maximum allowed distance
 	ALfloat MAX_DISTANCE_LOW; ///< maximum allowed distance
 	ALfloat REFERENCE_DISTANCE; ///< reference distance for sound
@@ -70,16 +69,6 @@ public:
 	virtual void resume();
 	virtual void pause();
 	virtual void update();
-    /// Return true if playing
-	virtual bool isPlaying()
-	{
-		return playing;
-	}
-    /// Return true if paused.
-	virtual bool isPaused() 
-	{
-		return paused;
-	}
 };
 
 
diff --git a/src/modules/graphic/ssggraph/OpenalSoundInterface.cpp b/src/modules/graphic/ssggraph/OpenalSoundInterface.cpp
index 6a0acaa0..05fbde0c 100644
--- a/src/modules/graphic/ssggraph/OpenalSoundInterface.cpp
+++ b/src/modules/graphic/ssggraph/OpenalSoundInterface.cpp
@@ -184,11 +184,10 @@ void OpenalSoundInterface::setNCars(int n_cars)
 	car_src = new SoundSource[n_cars];
 }
 
-
 Sound* OpenalSoundInterface::addSample (const char* filename, int flags, bool loop, bool static_pool)
 {
 	Sound* sound = new OpenalSound(filename, this, flags, loop, static_pool);
-    sound->setVolume(1.0f);
+    sound->setVolume(1.0f); // Will be automatically scaled down by the global gain.
 	sound_list.push_back(sound);
 	return sound;
 }
@@ -199,12 +198,12 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 	ALfloat listener_pos[3];
 	ALfloat listener_speed[3];
 	ALfloat listener_orientation[6];
-    ALfloat zeros[] = {0.0f, 0.0f, 0.0f};
+    static const ALfloat zeros[] = {0.0f, 0.0f, 0.0f};
 	
 	int i;
 	for (i = 0; i<3; i++) {
 		listener_pos[i] = p_obs[i];
-		listener_speed[i] = 0;// u_obs[i];
+		listener_speed[i] = 0;// u_obs[i]; // TODO: Try restoring this, needed !
 		listener_orientation[i] = c_obs[i];
 		listener_orientation[i+3] = a_obs[i];
 	}
@@ -220,7 +219,7 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 
 	for (i = 0; i<n_cars; i++) {
 		car_sound_data[i]->copyEngPri(engpri[i]);
-		int id = engpri[i].id;
+		const int id = engpri[i].id;
 		sgVec3 p;
 		sgVec3 u;
 		car_sound_data[id]->getCarPosition(p);
@@ -233,12 +232,12 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 
 	qsort((void*) engpri, n_cars, sizeof(SoundPri), &sortSndPriority);
 
-	int nsrc = MIN(sourcepool->getNbSources(), n_engine_sounds);
+	const int nsrc = MIN(sourcepool->getNbSources(), n_engine_sounds);
 
 	// Reverse order is important to gain free sources from stopped engine sounds
 	// before attempting to start new ones.
 	for (i = n_cars - 1; i >= 0; i--) {
-		int id = engpri[i].id;
+		const int id = engpri[i].id;
 		sgVec3 p;
 		sgVec3 u;
 		CarSoundData* sound_data = car_sound_data[id];
@@ -297,7 +296,6 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 		}
 	}
 
-	
 	// other looping sounds
 	road.snd = road_ride_sound;
 	sortSingleQueue (car_sound_data, &road, n_cars);
@@ -332,10 +330,9 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 	setMaxSoundCar (car_sound_data, &axle);
 
 	// On-off sounds
+	sgVec3 p, u;
 	for (id = 0; id<n_cars; id++) {
-		CarSoundData* sound_data = car_sound_data[id];
-		sgVec3 p;
-		sgVec3 u = {0, 0, 0};
+		const CarSoundData* sound_data = car_sound_data[id];
 		if (sound_data->crash) {
 			if (++curCrashSnd>=NB_CRASH_SOUND) {
 				curCrashSnd = 0;
@@ -343,7 +340,7 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 			sound_data->getCarPosition(p);
 			sound_data->getCarSpeed(u);
 			crash_sound[curCrashSnd]->setSource (p, u);
-			crash_sound[curCrashSnd]->setVolume (1.0f);
+			crash_sound[curCrashSnd]->setVolume (1.0f); // Will be automatically scaled down by the global gain.
 			crash_sound[curCrashSnd]->setPitch (1.0f);
 			crash_sound[curCrashSnd]->update();
 			crash_sound[curCrashSnd]->start();
@@ -353,7 +350,7 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 			sound_data->getCarPosition(p);
 			sound_data->getCarSpeed(u);
 			bang_sound->setSource (p, u);
-			bang_sound->setVolume (1.0f);
+			bang_sound->setVolume (1.0f); // Will be automatically scaled down by the global gain.
 			bang_sound->setPitch (1.0f);
 			bang_sound->update();
 			bang_sound->start();
@@ -363,7 +360,7 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 			sound_data->getCarPosition(p);
 			sound_data->getCarSpeed(u);
 			bottom_crash_sound->setSource (p, u);
-			bottom_crash_sound->setVolume (1.0f);
+			bottom_crash_sound->setVolume (1.0f); // Will be automatically scaled down by the global gain.
 			bottom_crash_sound->setPitch (1.0f);
 			bottom_crash_sound->update();
 			bottom_crash_sound->start();
@@ -374,16 +371,14 @@ void OpenalSoundInterface::update(CarSoundData** car_sound_data, int n_cars, sgV
 			sound_data->getCarSpeed(u);
 			gear_change_sound->setSource (p, u);
 			gear_change_sound->setReferenceDistance (1.0f);
-			gear_change_sound->setVolume (1.0f);
+			gear_change_sound->setVolume (1.0f); // Will be automatically scaled down by the global gain.
 			gear_change_sound->setPitch (1.0f);
 			gear_change_sound->update();
 			gear_change_sound->start();
 		}
 	}
-
 }
 
-
 void OpenalSoundInterface::initSharedSourcePool(void)
 {
 	const int nbdynsources = OSI_MAX_SOURCES - n_static_sources_in_use;
@@ -392,7 +387,6 @@ void OpenalSoundInterface::initSharedSourcePool(void)
 	GfLogInfo("  Dynamic sources: %d\n", sourcepool->getNbSources());
 }
 
-
 bool OpenalSoundInterface::getStaticSource(ALuint *source)
 {
 	// Do we have a source left for static assigned sources?
diff --git a/src/modules/graphic/ssggraph/PlibSound.cpp b/src/modules/graphic/ssggraph/PlibSound.cpp
index 20e167eb..572d263e 100644
--- a/src/modules/graphic/ssggraph/PlibSound.cpp
+++ b/src/modules/graphic/ssggraph/PlibSound.cpp
@@ -25,11 +25,9 @@
 /// Create a new PLib sound. It requires a scheduler to be set up
 /// and a filename to read data from.
 PlibSound::PlibSound(slScheduler* sched, const char* filename, int flags, bool loop)
-: Sound(flags)
+: Sound(flags, loop)
 {
 	this->sched = sched;
-	this->loop = loop;
-	MAX_VOL = 1.0f;
 	sample = new slSample (filename, sched);
 	if (flags & ACTIVE_VOLUME) {
 		volume_env = new slEnvelope(1, SL_SAMPLE_ONE_SHOT);
@@ -64,11 +62,6 @@ PlibSound::PlibSound(slScheduler* sched, const char* filename, int flags, bool l
 	if (flags & ACTIVE_LP_FILTER) {
 		lowpass_env->setStep(0, 0.0, 1.0f);
 	}
-	volume = 0.0f;
-	pitch = 1.0f;
-	lowpass = 1.0f;
-	playing = false;
-	paused = false;
 }
 
 /// Destructor.
@@ -119,7 +112,7 @@ void PlibSound::start()
 {
 	// TODO: consistency check?
 	if (loop) {
-		if (playing == false) {
+		if (!playing) {
 			playing = true;
 			sched->loopSample (sample);
 		}
@@ -132,7 +125,7 @@ void PlibSound::start()
 /// Stop the sample
 void PlibSound::stop()
 {
-	if (playing == true) {
+	if (playing) {
 		playing = false;
 		sched->stopSample (sample);
 	}
diff --git a/src/modules/graphic/ssggraph/PlibSound.h b/src/modules/graphic/ssggraph/PlibSound.h
index 1e985f45..d2d28da3 100644
--- a/src/modules/graphic/ssggraph/PlibSound.h
+++ b/src/modules/graphic/ssggraph/PlibSound.h
@@ -32,8 +32,6 @@ protected:
 	slEnvelope* pitch_env; ///< pitch envelope
 	slEnvelope* lowpass_env; ///< low pass filter envelope
 	slScheduler* sched; ///< plib sl scheduler (see sl.h)
-	bool playing; ///< Sound is playing
-    bool paused; ///< sound is paused
 public:
 	PlibSound(slScheduler* sched,
 			  const char* filename,
@@ -49,16 +47,6 @@ public:
 	virtual void resume();
 	virtual void pause();
 	virtual void update();
-    /// True if the sound is playing.
-	virtual bool isPlaying()
-	{
-		return playing;
-	}
-    /// Truye if the sound is paused.
-	virtual bool isPaused() 
-	{
-		return paused;
-	}
 };
 
 #endif
diff --git a/src/modules/graphic/ssggraph/Sound.cpp b/src/modules/graphic/ssggraph/Sound.cpp
index 78ef7bb1..d68a87eb 100644
--- a/src/modules/graphic/ssggraph/Sound.cpp
+++ b/src/modules/graphic/ssggraph/Sound.cpp
@@ -23,6 +23,24 @@
 #include "SoundInterface.h"
 
 
+/// Construct a sound.
+Sound::Sound(int flags, bool loop)
+{
+	this->flags = flags;
+	MAX_VOL = 1.0f;
+	volume = 0.0f;
+	pitch = 1.0f;
+	lowpass = 1.0f;
+	this->loop = loop;
+	playing = false;
+	paused = false;
+}
+
+/// Destructor
+Sound::~Sound()
+{
+}
+
 /// Set the volume \note effect not consistent across backends
 void Sound::setVolume(float vol)
 {
@@ -41,6 +59,47 @@ void Sound::setLPFilter(float lp)
 	this->lowpass = lp;
 }
 
+void Sound::setSource(sgVec3 p, sgVec3 u)
+{
+}
+
+float Sound::getVolume() const
+{
+	return volume;
+}
+
+float Sound::getPitch() const
+{
+	return pitch;
+}
+
+float Sound::getLPfilter() const
+{
+	return lowpass;
+}
+
+void Sound::setReferenceDistance (float dist)
+{
+	// Do nothing implementation.
+}
+
+void Sound::getSource (sgVec3 p, sgVec3 u) const
+{
+	// Do nothing implementation.
+}
+
+/// True if the sound is playing.
+bool Sound::isPlaying() const
+{
+	return playing;
+}
+
+/// True if the sound is paused.
+bool Sound::isPaused()  const
+{
+	return paused;
+}
+
 /// Create a sound source
 SoundSource::SoundSource()
 {
@@ -131,3 +190,4 @@ void SoundSource::setListener (sgVec3 p, sgVec3 u)
 		u_lis[i] = u[i];
 	}
 }
+
diff --git a/src/modules/graphic/ssggraph/Sound.h b/src/modules/graphic/ssggraph/Sound.h
index 7a7c7d5f..95b867f1 100644
--- a/src/modules/graphic/ssggraph/Sound.h
+++ b/src/modules/graphic/ssggraph/Sound.h
@@ -59,36 +59,38 @@ class Sound
 	float pitch; ///< Current pitch
 	float lowpass; ///< Current low pass filter
 	bool loop; ///< Whether it's a looping sound
+	bool playing; ///< Sound is playing
+    bool paused; ///< sound is paused
 
  public:
 
-	/// Consruct a sound.
-	Sound(int flags = (ACTIVE_VOLUME|ACTIVE_PITCH))
-	{
-		this->flags = flags;
-	}
+	/// Construct a sound.
+	Sound(int flags = (ACTIVE_VOLUME|ACTIVE_PITCH), bool loop = false);
 	
     /// Destructor
-	virtual ~Sound() {}
+	virtual ~Sound();
 	
 	virtual void setVolume(float vol);
 	virtual void setPitch(float pitch);
 	virtual void setLPFilter(float lp);
-	virtual void setSource(sgVec3 p, sgVec3 u) {}
-	virtual float getVolume() {return volume;}
-	virtual float getPitch() {return pitch;}
-	virtual float getLPfilter() {return lowpass;}
-	virtual void setReferenceDistance (float dist) {}
-	virtual void getSource (sgVec3 p, sgVec3 u) {}
+	virtual void setSource(sgVec3 p, sgVec3 u);
+	virtual void setReferenceDistance (float dist);
 	//virtual void setListener(sgVec3 p, sgVec3 u) = 0;
+
+	virtual float getVolume() const;
+	virtual float getPitch() const;
+	virtual float getLPfilter() const;
+	virtual void getSource (sgVec3 p, sgVec3 u) const;
+
 	virtual void play() = 0;
 	virtual void start() = 0;
 	virtual void stop() = 0;
 	virtual void resume() = 0;
 	virtual void pause() = 0;
 	virtual void update() = 0;
-	virtual bool isPlaying() = 0;
-	virtual bool isPaused() = 0;
+	
+	virtual bool isPlaying() const;
+	virtual bool isPaused() const;
 };
 
 /** Sound source management.
diff --git a/src/modules/graphic/ssggraph/grsound.cpp b/src/modules/graphic/ssggraph/grsound.cpp
index 424807e6..6153ce16 100644
--- a/src/modules/graphic/ssggraph/grsound.cpp
+++ b/src/modules/graphic/ssggraph/grsound.cpp
@@ -174,11 +174,11 @@ grShutdownSound(int ncars)
 
 
 
-float
+void
 grRefreshSound(tSituation *s, cGrCamera	*camera)
 {
 	if (sound_mode == DISABLED) {
-		return 0.0f;
+		return;
 	}
 
 	// TODO: Fix for a lot of cars. 
@@ -208,8 +208,6 @@ grRefreshSound(tSituation *s, cGrCamera	*camera)
 		sound_interface->update (car_sound_data, s->_ncars, 
 					 *p_camera, *u_camera, c_camera, *a_camera);
 	}
-
-	return 0.0f;
 }
 
 void grMuteSound(bool bOn)
diff --git a/src/modules/graphic/ssggraph/grsound.h b/src/modules/graphic/ssggraph/grsound.h
index e58c1377..8e1afe77 100644
--- a/src/modules/graphic/ssggraph/grsound.h
+++ b/src/modules/graphic/ssggraph/grsound.h
@@ -26,7 +26,7 @@ class cGrCamera;	//Declared in ""grcam.h"
 
 extern void grInitSound(tSituation* s, int ncars);
 extern void grShutdownSound(int ncars);
-extern float grRefreshSound(tSituation *s, cGrCamera *camera);
+extern void grRefreshSound(tSituation *s, cGrCamera *camera);
 extern void grMuteSound(bool bOn = true);
 
 #endif /* _GRSOUND_H_ */