diff --git a/engines/trecision/nl/ll/llinc.h b/engines/trecision/nl/ll/llinc.h
index 524e880d264..550c00b4adb 100644
--- a/engines/trecision/nl/ll/llinc.h
+++ b/engines/trecision/nl/ll/llinc.h
@@ -135,8 +135,8 @@ extern uint32 CurBufferSize;
 extern uint8 *MemoryArea;
 extern uint8 *SoundStartBuffer;
 // SOUND
-extern uint8 SoundSystemActive;
-extern uint8 SpeechTrackEnabled;
+extern bool SoundSystemActive;
+extern bool SpeechTrackEnabled;
 // MOUSE
 extern SDText curString;
 extern SDText oldString;
diff --git a/engines/trecision/nl/ll/llmouse.cpp b/engines/trecision/nl/ll/llmouse.cpp
index b4079d6f950..6f177b172a6 100644
--- a/engines/trecision/nl/ll/llmouse.cpp
+++ b/engines/trecision/nl/ll/llmouse.cpp
@@ -455,8 +455,8 @@ insave:
 
 	bool skipSave = false;
 	ch = 0;
-	for (; ;) {
-		CheckSystem();
+	for (;;) {
+		g_vm->CheckSystem();
 		Mouse(MCMD_UPDT);
 
 		GetKey();
@@ -517,7 +517,7 @@ insave:
 
 		for (; ;) {
 			g_vm->_keybInput = true;
-			CheckSystem();
+			g_vm->CheckSystem();
 			ch = GetKey();
 			FreeKey();
 
@@ -772,7 +772,7 @@ bool DataLoad() {
 	bool skipLoad = false;
 
 	for (;;) {
-		CheckSystem();
+		g_vm->CheckSystem();
 		Mouse(MCMD_UPDT);
 
 		GetKey();
@@ -941,7 +941,7 @@ bool DataLoad() {
 
 	actorStop();
 	nextStep();
-	CheckSystem();
+	g_vm->CheckSystem();
 
 	for (int a = FIRSTLINE; a < MAXY; a++)
 		wordset(g_vm->_video2 + CurRoomMaxX * a + CurScrollPageDx, 0, SCREENLEN);
diff --git a/engines/trecision/nl/ll/llscreen.cpp b/engines/trecision/nl/ll/llscreen.cpp
index cef98dce90b..8d7c3c560ab 100644
--- a/engines/trecision/nl/ll/llscreen.cpp
+++ b/engines/trecision/nl/ll/llscreen.cpp
@@ -46,9 +46,6 @@ int VertexNum, FaceNum, MatNum, LightNum;
 #define MAXLIGHT	40
 #define MAXMAT		20
 
-#define SOUND_OFF		0
-#define SOUND_ON		1
-
 int MaxMemory = 0;
 // GAME POINTER
 uint16 *ImagePointer;
@@ -91,8 +88,8 @@ STexture FTexture[MAXMAT];
 uint8 *MemoryArea;
 uint32 CurBufferSize;
 // SOUND
-uint8 SoundSystemActive;
-uint8 SpeechTrackEnabled = 0;
+bool SoundSystemActive;
+bool SpeechTrackEnabled = false;
 uint8 *SoundStartBuffer;
 // Temporary variables
 Common::SeekableReadStream *ff;
@@ -126,7 +123,7 @@ void openSys() {
 		}
 	}
 
-	SoundSystemActive = SOUND_OFF;
+	SoundSystemActive = false;
 
 	StartSoundSystem();
 
diff --git a/engines/trecision/nl/proto.h b/engines/trecision/nl/proto.h
index bbef3b41f39..b82981ea15e 100644
--- a/engines/trecision/nl/proto.h
+++ b/engines/trecision/nl/proto.h
@@ -205,7 +205,6 @@ void PaintString();
 void DoClearText();
 void DoSys(uint16 curObj);
 void SetRoom(uint16 r, bool b);
-void CheckSystem();
 char GetKey();
 char waitKey();
 void FreeKey();
diff --git a/engines/trecision/nl/sys/main.cpp b/engines/trecision/nl/sys/main.cpp
index f94b99f9538..3c3f0a0b9c9 100644
--- a/engines/trecision/nl/sys/main.cpp
+++ b/engines/trecision/nl/sys/main.cpp
@@ -49,17 +49,6 @@ void VMouseOFF();
 char waitKey();
 void wordset(void *dest, uint16 value, uint32 len);
 
-/* -----------------25/10/97 15.12-------------------
-					CheckSystem
- --------------------------------------------------*/
-void CheckSystem() {
-	//for ( int a=0; a<5; a++ )
-	{
-		g_vm->_animMgr->refreshAllAnimations();
-		g_vm->eventLoop();
-	}
-}
-
 /*-----------------16/01/97 20.53-------------------
 					GetKey
 --------------------------------------------------*/
@@ -97,7 +86,7 @@ char GetKey() {
 --------------------------------------------------*/
 char waitKey() {
 	while (g_vm->_curKey == Common::KEYCODE_INVALID)
-		CheckSystem();
+		g_vm->CheckSystem();
 
 	Common::KeyCode t = g_vm->_curKey;
 	g_vm->_curKey = Common::KEYCODE_INVALID;
@@ -126,7 +115,7 @@ void NlDelay(uint32 val) {
 	uint32 sv = ReadTime();
 
 	while ((sv + val) > ReadTime())
-		CheckSystem();
+		g_vm->CheckSystem();
 }
 
 /* -----------------24/06/98 15.00-------------------
@@ -138,7 +127,7 @@ void NlDissolve(int val) {
 
 	int lastv = 9000;
 	while ((sv + val) > (cv = ReadTime())) {
-		CheckSystem();
+		g_vm->CheckSystem();
 		if (lastv < (sv + val - cv))
 			continue;
 
@@ -205,7 +194,7 @@ void NlDissolve(int val) {
 					Mouse
 --------------------------------------------------*/
 void Mouse(MouseCmd opt) {
-	CheckSystem();
+	g_vm->CheckSystem();
 
 	switch (opt) {
 	// Update mouse
diff --git a/engines/trecision/nl/sys/sound.cpp b/engines/trecision/nl/sys/sound.cpp
index 913ce5a47ae..56b67161326 100644
--- a/engines/trecision/nl/sys/sound.cpp
+++ b/engines/trecision/nl/sys/sound.cpp
@@ -72,13 +72,12 @@ int16 SoundFadInVal;
 int16 SoundFadOutVal;
 
 extern uint8 *SpeechBuf[2];
-extern uint8  SpeechTrackEnabled;
+extern bool  SpeechTrackEnabled;
 void CloseSys(const char *str);
-void CheckSystem();
 void ReadExtraObj41D();
 void StopTalk();
 
-extern uint8 SoundSystemActive;
+extern bool SoundSystemActive;
 extern const char *_sysSentence[];
 int SpeechFileLen(const char *name);
 int SpeechFileRead(const char *name, unsigned char *buf);
@@ -148,7 +147,7 @@ void soundtimefunct() {
  --------------------------------------------------*/
 void StartSoundSystem() {
 	if (g_system->getMixer()->isReady())
-		SoundSystemActive = SOUND_ON;
+		SoundSystemActive = true;
 }
 
 /* -----------------05/08/97 16.35-------------------
@@ -157,9 +156,8 @@ void StartSoundSystem() {
 void StopSoundSystem() {
 	if (!SoundSystemActive)
 		return;
-	else if (SoundSystemActive == SOUND_ON) {
-		g_system->getMixer()->stopAll();
-	}
+
+	g_system->getMixer()->stopAll();
 }
 
 /* -----------------14/08/97 12.06-------------------
@@ -188,41 +186,37 @@ short LoadAudioWav(int num, uint8 *wav, int len) {
 					NLPlaySound
  --------------------------------------------------*/
 void NLPlaySound(int num) {
-	int channel;
 
 	if (!SoundSystemActive)
 		return;
-	else if (SoundSystemActive == SOUND_ON) {
-		channel = 2;
-		if (g_system->getMixer()->isSoundHandleActive(smp[channel])) {
-			g_system->getMixer()->stopHandle(smp[channel]);
-			playing[channel] = 0;
-		}
 
-		int volume = VOLUME(GSample[num]._volume);
-
-		if (GSample[num]._flag & SOUNDFLAG_SON) {
-			volume = 0;
-			smpvol[channel] = 0;
-		}
-
-		Audio::AudioStream *stream = NLSample[num].stream;
-		if (stream != nullptr && GSample[num]._flag & SOUNDFLAG_SLOOP)
-			stream = Audio::makeLoopingAudioStream(NLSample[num].stream, 0);
-
-		g_system->getMixer()->playStream(NLSample[num].type, &smp[channel], stream, -1, volume, 0, DisposeAfterUse::NO);
-
-		playing[channel] = num;
-
-		return;
+	int channel = 2;
+	if (g_system->getMixer()->isSoundHandleActive(smp[channel])) {
+		g_system->getMixer()->stopHandle(smp[channel]);
+		playing[channel] = 0;
 	}
+
+	int volume = VOLUME(GSample[num]._volume);
+
+	if (GSample[num]._flag & SOUNDFLAG_SON) {
+		volume = 0;
+		smpvol[channel] = 0;
+	}
+
+	Audio::AudioStream *stream = NLSample[num].stream;
+	if (stream != nullptr && GSample[num]._flag & SOUNDFLAG_SLOOP)
+		stream = Audio::makeLoopingAudioStream(NLSample[num].stream, 0);
+
+	g_system->getMixer()->playStream(NLSample[num].type, &smp[channel], stream, -1, volume, 0, DisposeAfterUse::NO);
+
+	playing[channel] = num;
 }
 
 /* -----------------14/08/97 16.30-------------------
 					NLStopSound
  --------------------------------------------------*/
 void NLStopSound(int num) {
-	if (!SoundSystemActive || SoundSystemActive != SOUND_ON)
+	if (!SoundSystemActive)
 		return;
 
 	for (int a = 2; a < SpeechChannel; a++) {
@@ -237,7 +231,7 @@ void NLStopSound(int num) {
 					SoundFadOut
  --------------------------------------------------*/
 void SoundFadOut() {
-	if (!SoundSystemActive || SoundSystemActive != SOUND_ON)
+	if (!SoundSystemActive)
 		return;
 
 	for (int a = 0; a < SAMPLEVOICES; a++) {	// spegne tutti i canali eccetto il background
@@ -255,7 +249,7 @@ void SoundFadOut() {
 					SoundFadIn
  --------------------------------------------------*/
 void SoundFadIn(int num) {
-	if (!SoundSystemActive || SoundSystemActive != SOUND_ON)
+	if (!SoundSystemActive)
 		return;
 
 	Audio::AudioStream *stream = NLSample[num].stream;
@@ -281,7 +275,7 @@ void WaitSoundFadEnd() {
 	}
 
 	while ((SoundFadInVal != (GSample[playing[StepChannel]]._volume * FADMULT)) && (playing[StepChannel] != 0) && (SoundFadOutVal != 0))
-		CheckSystem();
+		g_vm->CheckSystem();
 	SoundFadStatus = 0;
 
 	g_system->getMixer()->stopHandle(smp[BackChannel]);
@@ -395,21 +389,21 @@ int32 Talk(const char *name) {
 	StopTalk();
 
 	int Len = SpeechFileLen(name);
-	if ((Len > SPEECHSIZE) || (SoundSystemActive == SOUND_OFF)) {
-		SpeechTrackEnabled = 0;
-		return ((Len * 60L) / (11025));
+	if (Len > SPEECHSIZE || !SoundSystemActive) {
+		SpeechTrackEnabled = false;
+		return (Len * 60L) / 11025;
 	}
 	if (SpeechFileRead(name, SpeechBuf[0]) == 0) {
-		SpeechTrackEnabled = 0;
-		return ((Len * 60L) / (11025));
+		SpeechTrackEnabled = false;
+		return (Len * 60L) / 11025;
 	}
 
-	SpeechTrackEnabled = 1;
+	SpeechTrackEnabled = true;
 	if (LoadAudioWav(0xFFFF, SpeechBuf[0], Len))
 		Len *= 2;
 
-	if ((SoundSystemActive == SOUND_OFF))
-		SpeechTrackEnabled = 0;
+	if (!SoundSystemActive)
+		SpeechTrackEnabled = false;
 	else {
 		extern uint32 CharacterSpeakTime;
 		g_system->getMixer()->playStream(SpeechSample.type, &smp[SpeechChannel], SpeechSample.stream);
@@ -423,7 +417,7 @@ void StopTalk() {
 	if (SoundSystemActive)
 		g_system->getMixer()->stopHandle(smp[SpeechChannel]);
 
-	SpeechTrackEnabled = 0;
+	SpeechTrackEnabled = false;
 }
 
 } // End of namespace Trecision
diff --git a/engines/trecision/trecision.cpp b/engines/trecision/trecision.cpp
index 0362780d9d1..01ff4b97568 100644
--- a/engines/trecision/trecision.cpp
+++ b/engines/trecision/trecision.cpp
@@ -465,4 +465,13 @@ void TrecisionEngine::LoadAll() {
 
 	dataNl.close();
 }
+
+/*-------------------------------------------------
+					CheckSystem
+ --------------------------------------------------*/
+void TrecisionEngine::CheckSystem() {
+	_animMgr->refreshAllAnimations();
+	eventLoop();
+}
+
 } // End of namespace Trecision
diff --git a/engines/trecision/trecision.h b/engines/trecision/trecision.h
index 654ef6dde79..20728e002f1 100644
--- a/engines/trecision/trecision.h
+++ b/engines/trecision/trecision.h
@@ -55,6 +55,9 @@ public:
 	void setInventoryStart(uint8 StartIcon, uint8 StartLine);
 	void doInventory();
 
+	void CheckSystem();
+
+
 	uint16 _curRoom;
 	uint16 _oldRoom;
 	SRoom _room[MAXROOMS];