Added front/rear speaker balance (actually the master/slave SCSP balance). Balance setting is stored in CSoundBoardConfig and can be set on the command line (-balance) or config file (Balance). Valid range is 100 (front speaker volume doubled, rear muted) to -100. The default is 0, both sets at full volume. Balance is applied in the SCSP core before overall sound and music volume settings.

Src/Model3/DSB.h

@@ -53,7 +53,7 @@ public:
 	bool	emulateDSB;	// DSB emulation (enabled if true)
 	
 	// Sound (SCSP) volume (0-200, 100 being full amplitude)
-	inline void SetSoundVolume(unsigned vol)
+	inline void SetSoundVolume(int vol)
 	{
 		if (vol > 200)
 		{
@@ -61,7 +61,13 @@ public:
 			vol = 100;
 		}
 		
-		soundVol = vol;
+		if (vol < 0)
+		{
+			ErrorLog("Sound volume cannot be negative; setting to 0%%.\n");
+			vol = 0;
+		}
+		
+		soundVol = (unsigned) vol;
 	}
 	
 	inline unsigned GetSoundVolume(void)
@@ -70,7 +76,7 @@ public:
 	}
 	
 	// Music (DSB MPEG) volume (0-200)
-	inline void SetMusicVolume(unsigned vol)
+	inline void SetMusicVolume(int vol)
 	{
 		if (vol > 200)
 		{
@@ -78,7 +84,13 @@ public:
 			vol = 100;
 		}
 		
-		musicVol = vol;
+		if (vol < 0)
+		{
+			ErrorLog("Music volume cannot be negative; setting to 0%%.\n");
+			vol = 0;
+		}
+		
+		musicVol = (unsigned) vol;
 	}
 	
 	inline unsigned GetMusicVolume(void)

Src/Model3/SoundBoard.h

@@ -43,11 +43,38 @@ class CSoundBoardConfig
 public:
 	bool	emulateSound;	// sound board emulation (enabled if true)
 	
+	// Master/slave SCSP relative balance (0-100, with 100 meaning master volume doubled, slave silenced)
+	inline void SetSCSPBalance(int bal)
+	{
+		if (bal > 100)
+		{
+			ErrorLog("Front/rear balance cannot exceed 100%%; setting to 100%%.\n");
+			bal = 100;
+		}
+		
+		if (bal < -100)
+		{
+			ErrorLog("Front/rear balance cannot be less than -100%%; setting to -100%%.\n");
+			bal = -100;
+		}
+		
+		scspBalance = bal;
+	}
+	
+	inline int GetSCSPBalance(void)
+	{
+		return scspBalance;
+	}
+	
 	// Defaults
 	CSoundBoardConfig(void)
 	{
 		emulateSound = true;
+		scspBalance = 50;
 	}
+	
+private:
+	int	scspBalance;
 };
 
 /*

Src/OSD/SDL/Main.cpp

@@ -355,6 +355,7 @@ static bool ConfigureInputs(CInputs *Inputs, bool configure)
 static void ApplySettings(CINIFile *INI, const char *section)
 {
 	unsigned	x;
+	int			y;
 	string		String;
 	
 	// Model 3
@@ -374,6 +375,8 @@ static void ApplySettings(CINIFile *INI, const char *section)
 		g_Config.SetSoundVolume(x);
 	if (OKAY == INI->Get(section, "MusicVolume", x))
 		g_Config.SetMusicVolume(x);
+	if (OKAY == INI->Get(section, "Balance", y))
+		g_Config.SetSCSPBalance(y);
 	if (OKAY == INI->Get(section, "EmulateSound", x))
 		g_Config.emulateSound = x ? true : false;
 	if (OKAY == INI->Get(section, "EmulateDSB", x))
@@ -464,6 +467,7 @@ static void LogConfig(void)
 	
 	// CSoundBoardConfig
 	InfoLog("\tEmulateSound                  = %d", g_Config.emulateSound);
+	InfoLog("\tBalance                       = %d", g_Config.GetSCSPBalance());
 	
 	// CDSBConfig
 	InfoLog("\tEmulateDSB                    = %d", g_Config.emulateDSB);
@@ -1205,7 +1209,7 @@ static void Help(void)
 	puts("    -print-games           List supported games and quit");
 	puts("");
 	puts("Core Options:");
-	printf("    -ppc-frequency=<f>     PowerPC frequency in MHz [Default: %d]\n", g_Config.GetPowerPCFrequency());
+	printf("    -ppc-frequency=<freq>  PowerPC frequency in MHz [Default: %d]\n", g_Config.GetPowerPCFrequency());
 	puts("    -no-threads            Disable multi-threading");
 	puts("");
 	puts("Video Options:");
@@ -1218,8 +1222,9 @@ static void Help(void)
 	puts("    -print-gl-info         Print OpenGL driver information and quit");
 	puts("");
 	puts("Audio Options:");
-	puts("    -sound-volume=<v>      Volume of sound effects in % [Default: 100]");
+	puts("    -sound-volume=<vol>    Volume of sound effects in % [Default: 100]");
-	puts("    -music-volume=<v>      Volume of MPEG music in % [Default: 100]");
+	puts("    -music-volume=<vol>    Volume of MPEG music in % [Default: 100]");
+	puts("    -balance=<bal>         Relative front/rear balance in % front [Default: 0]");
 	puts("    -flip-stereo           Swap left and right audio channels");
 	puts("    -no-sound              Disable sound board emulation (sound effects)");
 	puts("    -no-dsb                Disable Digital Sound Board (MPEG music)");
@@ -1277,6 +1282,7 @@ int main(int argc, char **argv)
 #endif // SUPERMODEL_DEBUGGER
 	char		*inputSystem = NULL;	// use default input system
 	unsigned	n;
+	int			m;
 	UINT32		addr;
 
 	Title();
@@ -1358,6 +1364,14 @@ int main(int argc, char **argv)
 			else
 				CmdLine.Set("Global", "MusicVolume", n);
 		}
+		else if (!strncmp(argv[i],"-balance",8))
+		{
+			ret = sscanf(&argv[i][8],"=%d",&m);
+			if (ret != 1)
+				ErrorLog("'-balance' requires a front/rear balance setting.");
+			else
+				CmdLine.Set("Global", "Balance", m);
+		}
 		else if (!strcmp(argv[i], "-flip-stereo"))
 		{
 			n = 1;

Src/Sound/SCSP.cpp

@@ -968,7 +968,7 @@ void SCSP_w8(unsigned int addr,unsigned char val)
 		int slot=addr/0x20;
 		addr&=0x1f;
 		//DebugLog("Slot %02X Reg %02X write byte %04X\n",slot,addr^1,val);
-		//printf("Slot %02X Reg %02X write byte %04X\n",slot,addr^1,val);
+		//printf("\tSlot %02X Reg %02X write byte %04X\n",slot,addr^1,val);
 		*(unsigned char *) &(SCSP->Slots[slot].datab[addr^1]) = val;
 		SCSP_UpdateSlotReg(slot,(addr^1)&0x1f);
 	}
@@ -1008,7 +1008,7 @@ void SCSP_w16(unsigned int addr,unsigned short val)
 		int slot=addr/0x20;
 		addr&=0x1f;
 		//DebugLog("Slot %02X Reg %02X write word %04X\n",slot,addr,val);
-		//printf("Slot %02X Reg %02X write word %04X\n",slot,addr,val);
+		//printf("\tSlot %02X Reg %02X write word %04X\n",slot,addr,val);
 		*(unsigned short *) &(SCSP->Slots[slot].datab[addr]) = val;
 		SCSP_UpdateSlotReg(slot,addr&0x1f);
 	}
@@ -1042,13 +1042,12 @@ void SCSP_w16(unsigned int addr,unsigned short val)
 void SCSP_w32(unsigned int addr,unsigned int val)
 {
 	addr&=0xffff;
-	
 	if(addr<0x400)
 	{
 		int slot=addr/0x20;
 		addr&=0x1f;
 		//DebugLog("Slot %02X Reg %02X write dword %08X\n",slot,addr,val);
-		//printf("Slot %02X Reg %02X write dword %08X\n",slot,addr,val);
+		//printf("\tSlot %02X Reg %02X write dword %08X\n",slot,addr,val);
 		rotl(val, 16);
 
 		*(unsigned int *) &(SCSP->Slots[slot].datab[addr]) = val;
@@ -1765,6 +1764,19 @@ void SCSP_DoMasterSamples(int nsamples)
 	int slice=12000000/(SysFPS*nsamples);	// 68K cycles/sample
 	static int lastdiff=0;
 	
+	/*
+	 * Compute relative master/slave SCSP balance (note: master is often used 
+	 * for the front speakers). Equal balance is a 1.0 scale factor for both.
+	 * When one SCSP is fully attenuated, the other's samples will be multiplied
+	 * by 2.
+	 */
+	float balance = (float) g_Config.GetSCSPBalance() / 100.0f;
+	float masterBalance = 1.0f+balance;
+	float slaveBalance = 1.0f-balance;
+
+	/*
+	 * Generate samples
+	 */
 	for(int s=0;s<nsamples;++s)
 	{
 		signed int smpl=0;
@@ -1778,12 +1790,12 @@ void SCSP_DoMasterSamples(int nsamples)
 				unsigned short Enc=((TL(slot))<<0x8)|((DIPAN(slot))<<0x0)|((DISDL(slot))<<0x5);
 				RBUFDST=SCSPs[0].RINGBUF+SCSPs[0].BUFPTR;
 				signed int sample;
-				//signed int sample=SCSP_UpdateSlot(slot);
+				//signed int sample=(int) (masterBalance*(float)SCSP_UpdateSlot(slot));
 				//if(SA(slot)!=0x2ccf4)
 				/*if(SA(slot)!=0x1c77e)
 					sample=0;
 				else*/
-					sample=SCSP_UpdateSlot(slot);
+					sample= (int) (masterBalance*(float)SCSP_UpdateSlot(slot));
 
 				
 				/*unsigned char ef=EFSDL(slot);
@@ -1816,7 +1828,7 @@ void SCSP_DoMasterSamples(int nsamples)
 					_SLOT *slot=SCSPs[1].Slots+sl;
 					unsigned short Enc=((TL(slot))<<0x8)|((DIPAN(slot))<<0x0)|((DISDL(slot))<<0x5);
 					RBUFDST=SCSPs[1].RINGBUF+SCSPs[1].BUFPTR;
-					signed int sample=SCSP_UpdateSlot(slot);
+					signed int sample=(int) (slaveBalance*(float)SCSP_UpdateSlot(slot));
 #ifdef USEDSP
 					SCSPDSP_SetSample(&SCSPs[1].DSP,(sample*LPANTABLE[(Enc|0xE0)&0xFFE0])>>(SHIFT+3),ISEL(slot),IMXL(slot));
 #endif
@@ -1847,8 +1859,10 @@ void SCSP_DoMasterSamples(int nsamples)
 			if(ef)
 			{
 				unsigned short Enc=0|((EFPAN(slot))<<0x0)|((EFSDL(slot))<<0x5);
-				smpl+=(SCSPs[0].DSP.EFREG[i]*LPANTABLE[Enc])>>SHIFT;
+				signed int leftSample  = (int) (masterBalance*(float)((SCSPs[0].DSP.EFREG[i]*LPANTABLE[Enc])>>SHIFT));
-				smpr+=(SCSPs[0].DSP.EFREG[i]*RPANTABLE[Enc])>>SHIFT;
+				signed int rightSample = (int) (masterBalance*(float)((SCSPs[0].DSP.EFREG[i]*RPANTABLE[Enc])>>SHIFT));
+				smpl+=leftSample;
+				smpr+=rightSample;
 			}
 			if(HasSlaveSCSP)
 			{
@@ -1857,8 +1871,10 @@ void SCSP_DoMasterSamples(int nsamples)
 				if(ef)
 				{
 					unsigned short Enc=0|((EFPAN(slot))<<0x0)|((EFSDL(slot))<<0x5);
-					smpl+=(SCSPs[1].DSP.EFREG[i]*LPANTABLE[Enc])>>SHIFT;
+					signed int leftSample  = (int) (slaveBalance*(float)((SCSPs[1].DSP.EFREG[i]*LPANTABLE[Enc])>>SHIFT));
-					smpr+=(SCSPs[1].DSP.EFREG[i]*RPANTABLE[Enc])>>SHIFT;
+					signed int rightSample = (int) (slaveBalance*(float)((SCSPs[1].DSP.EFREG[i]*RPANTABLE[Enc])>>SHIFT));
+					smpl+=leftSample;
+					smpr+=rightSample;
 				}
 			}
 		}