diff --git a/.gitignore b/.gitignore
index a5436e938..39aecb98e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,3 +17,4 @@ android/app/build/
 android/app/.cxx/
 .vs/
 CMakeSettings.json
+CMakePresets.json
diff --git a/src/engine/dispatchContainer.cpp b/src/engine/dispatchContainer.cpp
index d175b2539..41adbb200 100644
--- a/src/engine/dispatchContainer.cpp
+++ b/src/engine/dispatchContainer.cpp
@@ -30,6 +30,7 @@
 #include "platform/arcade.h"
 #include "platform/tx81z.h"
 #include "platform/ym2203.h"
+#include "platform/ym2203ext.h"
 #include "platform/ym2608.h"
 #include "platform/ym2610.h"
 #include "platform/ym2610ext.h"
@@ -240,6 +241,9 @@ void DivDispatchContainer::init(DivSystem sys, DivEngine* eng, int chanCount, do
     case DIV_SYSTEM_OPN:
       dispatch=new DivPlatformYM2203;
       break;
+    case DIV_SYSTEM_OPN_EXT:
+      dispatch=new DivPlatformYM2203Ext;
+      break;
     case DIV_SYSTEM_PC98:
       dispatch=new DivPlatformYM2608;
       break;
diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 0a6fc7e90..9fcb85008 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -885,6 +885,7 @@ bool DivEngine::addSystem(DivSystem which) {
   return true;
 }
 
+// TODO: maybe issue with subsongs?
 bool DivEngine::removeSystem(int index, bool preserveOrder) {
   if (song.systemLen<=1) {
     lastError="cannot remove the last one";
diff --git a/src/engine/platform/ay.cpp b/src/engine/platform/ay.cpp
index dbc5aa82b..94546ed1d 100644
--- a/src/engine/platform/ay.cpp
+++ b/src/engine/platform/ay.cpp
@@ -27,7 +27,7 @@
 #define rWrite(a,v) if (!skipRegisterWrites) {pendingWrites[a]=v;}
 #define immWrite(a,v) if (!skipRegisterWrites) {writes.emplace(regRemap(a),v); if (dumpWrites) {addWrite(regRemap(a),v);} }
 
-#define CHIP_DIVIDER 8
+#define CHIP_DIVIDER ((sunsoft||clockSel)?16:8)
 
 const char* regCheatSheetAY[]={
   "FreqL_A", "0",
@@ -589,6 +589,7 @@ void DivPlatformAY8910::poke(std::vector<DivRegWrite>& wlist) {
 }
 
 void DivPlatformAY8910::setFlags(unsigned int flags) {
+  clockSel=(flags>>7)&1;
   switch (flags&15) {
     case 1:
       chipClock=COLOR_PAL*2.0/5.0;
@@ -620,6 +621,12 @@ void DivPlatformAY8910::setFlags(unsigned int flags) {
     case 10:
       chipClock=2097152;
       break;
+    case 11:
+      chipClock=COLOR_NTSC;
+      break;
+    case 12:
+      chipClock=3600000;
+      break;
     default:
       chipClock=COLOR_NTSC/2.0;
       break;
@@ -632,7 +639,7 @@ void DivPlatformAY8910::setFlags(unsigned int flags) {
   if (ay!=NULL) delete ay;
   switch ((flags>>4)&3) {
     case 1:
-      ay=new ym2149_device(rate);
+      ay=new ym2149_device(rate,clockSel);
       sunsoft=false;
       intellivision=false;
       break;
@@ -654,7 +661,7 @@ void DivPlatformAY8910::setFlags(unsigned int flags) {
   }
   ay->device_start();
 
-  stereo=flags>>6;
+  stereo=(flags>>6)&1;
 }
 
 int DivPlatformAY8910::init(DivEngine* p, int channels, int sugRate, unsigned int flags) {
diff --git a/src/engine/platform/ay.h b/src/engine/platform/ay.h
index b257e3bbc..f93d34bdc 100644
--- a/src/engine/platform/ay.h
+++ b/src/engine/platform/ay.h
@@ -70,7 +70,7 @@ class DivPlatformAY8910: public DivDispatch {
     int delay;
 
     bool extMode;
-    bool stereo, sunsoft, intellivision;
+    bool stereo, sunsoft, intellivision, clockSel;
     bool ioPortA, ioPortB;
     unsigned char portAVal, portBVal;
   
diff --git a/src/engine/platform/ay8930.cpp b/src/engine/platform/ay8930.cpp
index 6fb340968..8ec2aea2b 100644
--- a/src/engine/platform/ay8930.cpp
+++ b/src/engine/platform/ay8930.cpp
@@ -27,7 +27,7 @@
 #define rWrite(a,v) if (!skipRegisterWrites) {pendingWrites[a]=v;}
 #define immWrite2(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
 
-#define CHIP_DIVIDER 4
+#define CHIP_DIVIDER (clockSel?8:4)
 
 const char* regCheatSheetAY8930[]={
   "FreqL_A", "00",
@@ -64,7 +64,7 @@ const char* regCheatSheetAY8930[]={
 void DivPlatformAY8930::immWrite(unsigned char a, unsigned char v) {
   if ((int)bank!=(a>>4)) {
     bank=a>>4;
-    immWrite2(0x0d, 0xa0|(bank<<4)|ayEnvMode[0]);
+    immWrite2(0x0d, 0xa0|(bank<<4)|chan[0].envelope.mode);
   }
   if (a==0x0d) {
     immWrite2(0x0d,0xa0|(bank<<4)|(v&15));
@@ -258,8 +258,8 @@ void DivPlatformAY8930::tick(bool sysTick) {
       rWrite(0x16+i,chan[i].std.ex1.val);
     }
     if (chan[i].std.ex2.had) {
-      ayEnvMode[i]=chan[i].std.ex2.val;
-      rWrite(regMode[i],ayEnvMode[i]);
+      chan[i].envelope.mode=chan[i].std.ex2.val;
+      rWrite(regMode[i],chan[i].envelope.mode);
     }
     if (chan[i].std.ex3.had) {
       chan[i].autoEnvNum=chan[i].std.ex3.val;
@@ -296,29 +296,29 @@ void DivPlatformAY8930::tick(bool sysTick) {
       if (chan[i].keyOn) chan[i].keyOn=false;
       if (chan[i].keyOff) chan[i].keyOff=false;
       if (chan[i].freqChanged && chan[i].autoEnvNum>0 && chan[i].autoEnvDen>0) {
-        ayEnvPeriod[i]=(chan[i].freq*chan[i].autoEnvDen/chan[i].autoEnvNum)>>4;
-        immWrite(regPeriodL[i],ayEnvPeriod[i]);
-        immWrite(regPeriodH[i],ayEnvPeriod[i]>>8);
+        chan[i].envelope.period=(chan[i].freq*chan[i].autoEnvDen/chan[i].autoEnvNum)>>4;
+        immWrite(regPeriodL[i],chan[i].envelope.period);
+        immWrite(regPeriodH[i],chan[i].envelope.period>>8);
       }
       chan[i].freqChanged=false;
     }
 
-    if (ayEnvSlide[i]!=0) {
-      ayEnvSlideLow[i]+=ayEnvSlide[i];
-      while (ayEnvSlideLow[i]>7) {
-        ayEnvSlideLow[i]-=8;
-        if (ayEnvPeriod[i]<0xffff) {
-          ayEnvPeriod[i]++;
-          immWrite(regPeriodL[i],ayEnvPeriod[i]);
-          immWrite(regPeriodH[i],ayEnvPeriod[i]>>8);
+    if (chan[i].envelope.slide!=0) {
+      chan[i].envelope.slideLow+=chan[i].envelope.slide;
+      while (chan[i].envelope.slideLow>7) {
+        chan[i].envelope.slideLow-=8;
+        if (chan[i].envelope.period<0xffff) {
+          chan[i].envelope.period++;
+          immWrite(regPeriodL[i],chan[i].envelope.period);
+          immWrite(regPeriodH[i],chan[i].envelope.period>>8);
         }
       }
-      while (ayEnvSlideLow[i]<-7) {
-        ayEnvSlideLow[i]+=8;
-        if (ayEnvPeriod[i]>0) {
-          ayEnvPeriod[i]--;
-          immWrite(regPeriodL[i],ayEnvPeriod[i]);
-          immWrite(regPeriodH[i],ayEnvPeriod[i]>>8);
+      while (chan[i].envelope.slideLow<-7) {
+        chan[i].envelope.slideLow+=8;
+        if (chan[i].envelope.period>0) {
+          chan[i].envelope.period--;
+          immWrite(regPeriodL[i],chan[i].envelope.period);
+          immWrite(regPeriodH[i],chan[i].envelope.period>>8);
         }
       }
     }
@@ -435,8 +435,8 @@ int DivPlatformAY8930::dispatch(DivCommand c) {
       rWrite(0x06,c.value);
       break;
     case DIV_CMD_AY_ENVELOPE_SET:
-      ayEnvMode[c.chan]=c.value>>4;
-      rWrite(regMode[c.chan],ayEnvMode[c.chan]);
+      chan[c.chan].envelope.mode=c.value>>4;
+      rWrite(regMode[c.chan],chan[c.chan].envelope.mode);
       if (c.value&15) {
         chan[c.chan].psgMode|=4;
       } else {
@@ -449,19 +449,19 @@ int DivPlatformAY8930::dispatch(DivCommand c) {
       }
       break;
     case DIV_CMD_AY_ENVELOPE_LOW:
-      ayEnvPeriod[c.chan]&=0xff00;
-      ayEnvPeriod[c.chan]|=c.value;
-      immWrite(regPeriodL[c.chan],ayEnvPeriod[c.chan]);
-      immWrite(regPeriodH[c.chan],ayEnvPeriod[c.chan]>>8);
+      chan[c.chan].envelope.period&=0xff00;
+      chan[c.chan].envelope.period|=c.value;
+      immWrite(regPeriodL[c.chan],chan[c.chan].envelope.period);
+      immWrite(regPeriodH[c.chan],chan[c.chan].envelope.period>>8);
       break;
     case DIV_CMD_AY_ENVELOPE_HIGH:
-      ayEnvPeriod[c.chan]&=0xff;
-      ayEnvPeriod[c.chan]|=c.value<<8;
-      immWrite(regPeriodL[c.chan],ayEnvPeriod[c.chan]);
-      immWrite(regPeriodH[c.chan],ayEnvPeriod[c.chan]>>8);
+      chan[c.chan].envelope.period&=0xff;
+      chan[c.chan].envelope.period|=c.value<<8;
+      immWrite(regPeriodL[c.chan],chan[c.chan].envelope.period);
+      immWrite(regPeriodH[c.chan],chan[c.chan].envelope.period>>8);
       break;
     case DIV_CMD_AY_ENVELOPE_SLIDE:
-      ayEnvSlide[c.chan]=c.value;
+      chan[c.chan].envelope.slide=c.value;
       break;
     case DIV_CMD_AY_NOISE_MASK_AND:
       ayNoiseAnd=c.value;
@@ -526,9 +526,9 @@ void DivPlatformAY8930::muteChannel(int ch, bool mute) {
 void DivPlatformAY8930::forceIns() {
   for (int i=0; i<3; i++) {
     chan[i].insChanged=true;
-    immWrite(regPeriodL[i],ayEnvPeriod[i]);
-    immWrite(regPeriodH[i],ayEnvPeriod[i]>>8);
-    immWrite(regMode[i],ayEnvMode[i]);
+    immWrite(regPeriodL[i],chan[i].envelope.period);
+    immWrite(regPeriodH[i],chan[i].envelope.period>>8);
+    immWrite(regMode[i],chan[i].envelope.mode);
   }
 }
 
@@ -556,10 +556,10 @@ void DivPlatformAY8930::reset() {
     chan[i]=DivPlatformAY8930::Channel();
     chan[i].std.setEngine(parent);
     chan[i].vol=31;
-    ayEnvPeriod[i]=0;
-    ayEnvMode[i]=0;
-    ayEnvSlide[i]=0;
-    ayEnvSlideLow[i]=0;
+    chan[i].envelope.period=0;
+    chan[i].envelope.mode=0;
+    chan[i].envelope.slide=0;
+    chan[i].envelope.slideLow=0;
   }
   if (dumpWrites) {
     addWrite(0xffffffff,0);
@@ -610,6 +610,7 @@ void DivPlatformAY8930::poke(std::vector<DivRegWrite>& wlist) {
 }
 
 void DivPlatformAY8930::setFlags(unsigned int flags) {
+  clockSel=(flags>>7)&1;
   switch (flags&15) {
     case 1:
       chipClock=COLOR_PAL*2.0/5.0;
@@ -641,6 +642,12 @@ void DivPlatformAY8930::setFlags(unsigned int flags) {
     case 10:
       chipClock=2097152;
       break;
+    case 11:
+      chipClock=COLOR_NTSC;
+      break;
+    case 12:
+      chipClock=3600000;
+      break;
     default:
       chipClock=COLOR_NTSC/2.0;
       break;
@@ -650,7 +657,7 @@ void DivPlatformAY8930::setFlags(unsigned int flags) {
     oscBuf[i]->rate=rate;
   }
 
-  stereo=flags>>6;
+  stereo=(flags>>6)&1;
 }
 
 int DivPlatformAY8930::init(DivEngine* p, int channels, int sugRate, unsigned int flags) {
@@ -662,7 +669,7 @@ int DivPlatformAY8930::init(DivEngine* p, int channels, int sugRate, unsigned in
     oscBuf[i]=new DivDispatchOscBuffer;
   }
   setFlags(flags);
-  ay=new ay8930_device(rate);
+  ay=new ay8930_device(rate,clockSel);
   ay->device_start();
   ayBufLen=65536;
   for (int i=0; i<3; i++) ayBuf[i]=new short[ayBufLen];
diff --git a/src/engine/platform/ay8930.h b/src/engine/platform/ay8930.h
index 5f477e123..67420f48c 100644
--- a/src/engine/platform/ay8930.h
+++ b/src/engine/platform/ay8930.h
@@ -27,6 +27,17 @@
 class DivPlatformAY8930: public DivDispatch {
   protected:
     struct Channel {
+      struct Envelope {
+        unsigned char mode;
+        unsigned short period;
+        short slideLow;
+        short slide;
+        Envelope():
+          mode(0),
+          period(0),
+          slideLow(0),
+          slide(0) {}
+      } envelope;
       unsigned char freqH, freqL;
       int freq, baseFreq, note, pitch, pitch2;
       int ins;
@@ -59,16 +70,12 @@ class DivPlatformAY8930: public DivDispatch {
 
     int delay;
 
-    bool extMode, stereo;
+    bool extMode, stereo, clockSel;
     bool ioPortA, ioPortB;
     unsigned char portAVal, portBVal;
   
     short oldWrites[32];
     short pendingWrites[32];
-    unsigned char ayEnvMode[3];
-    unsigned short ayEnvPeriod[3];
-    short ayEnvSlideLow[3];
-    short ayEnvSlide[3];
     short* ayBuf[3];
     size_t ayBufLen;
 
diff --git a/src/engine/platform/sound/ay8910.cpp b/src/engine/platform/sound/ay8910.cpp
index 4d19e7de5..3dddf82c5 100644
--- a/src/engine/platform/sound/ay8910.cpp
+++ b/src/engine/platform/sound/ay8910.cpp
@@ -1021,10 +1021,8 @@ void ay8910_device::ay8910_write_reg(int r, int v)
 			m_tone[2].set_duty(m_regs[AY_CDUTY]);
 			break;
 		case AY_NOISEAND:
-      m_noise_and=m_regs[AY_NOISEAND];
-      break;
 		case AY_NOISEOR:
-      m_noise_or=m_regs[AY_NOISEOR];
+			// No action required
 			break;
 		default:
 			m_regs[r] = 0; // reserved, set as 0
@@ -1047,7 +1045,7 @@ void ay8910_device::sound_stream_update(short** outputs, int outLen)
 	if (!m_ready)
 	{
 		for (int chan = 0; chan < m_streams; chan++)
-      memset(outputs[chan],0,outLen*sizeof(short));
+			memset(outputs[chan],0,outLen*sizeof(short));
 	}
 
 	/* The 8910 has three outputs, each output is the mix of one of the three */
@@ -1063,8 +1061,8 @@ void ay8910_device::sound_stream_update(short** outputs, int outLen)
 		for (int chan = 0; chan < NUM_CHANNELS; chan++)
 		{
 			tone = &m_tone[chan];
-			const int period = std::max<int>(1,tone->period);
-			tone->count += is_expanded_mode() ? 16 : (m_feature & PSG_HAS_EXPANDED_MODE) ? 2 : 1;
+			const int period = tone->period * (m_step_mul << 1);
+			tone->count += is_expanded_mode() ? 32 : ((m_feature & PSG_HAS_EXPANDED_MODE) ? 1 : 2);
 			while (tone->count >= period)
 			{
 				tone->duty_cycle = (tone->duty_cycle - 1) & 0x1f;
@@ -1073,8 +1071,8 @@ void ay8910_device::sound_stream_update(short** outputs, int outLen)
 			}
 		}
 
-		m_count_noise++;
-		if (m_count_noise >= noise_period())
+		const int period_noise = (int)(noise_period()) * m_step_mul;
+		if ((++m_count_noise) >= period_noise)
 		{
 			/* toggle the prescaler output. Noise is no different to
 			 * channels.
@@ -1082,39 +1080,27 @@ void ay8910_device::sound_stream_update(short** outputs, int outLen)
 			m_count_noise = 0;
 			m_prescale_noise = (m_prescale_noise + 1) & ((m_feature & PSG_HAS_EXPANDED_MODE) ? 3 : 1);
 
-			if (!m_prescale_noise || is_expanded_mode()) // AY8930 noise generator rate is twice compares as compatibility mode
+			if (is_expanded_mode()) // AY8930 noise generator rate is twice? compares as compatibility mode
 			{
-        if (is_expanded_mode()) {
-          // This is called "Noise value" on the docs, but is a counter whose period is determined by the LFSR.
-          // Using AND/OR gates, specific periods can be "filtered" out.
-          // A square wave can be generated through this behavior, which can be used for crude AM pulse width modulation.
-          
-          // The period of the noise is determined by this value.
-          // The least significant byte of the LFSR is bitwise ANDed with the AND mask, and then bitwise ORed with the OR mask.
-          unsigned int noiseValuePeriod = ((m_rng & 0xFF & m_noise_and) | m_noise_or);
-          
-          // Clock the noise value.
-          if (m_noise_value >= noiseValuePeriod) {
-              m_noise_value = 0;
-              
-              // When everything is finally said and done, a 1bit latch is flipped.
-              // This is the final output of the noise, to be multiplied by the tone and envelope generators of the channel.
-              m_noise_latch ^= 1;
-              
-              // The 17-bit LFSR is updated, using an XOR across bits 0 and 2.
-              unsigned int feedback = (m_rng & 1) ^ ((m_rng >> 2) & 1);
-              m_rng >>= 1;
-              m_rng |= (feedback << 16);
-          }
-          m_noise_value++;
-        } else {
-          /* The Random Number Generator of the 8910 is a 17-bit shift */
-          /* register. The input to the shift register is bit0 XOR bit3 */
-          /* (bit0 is the output). This was verified on AY-3-8910 and YM2149 chips. */
-          m_rng ^= (((m_rng & 1) ^ ((m_rng >> 3) & 1)) << 17);
-          m_rng >>= 1;
-        }
+				// This is called "Noise value" on the docs, but is a counter whose period is determined by the LFSR.
+				// Using AND/OR gates, specific periods can be "filtered" out.
+				// A square wave can be generated through this behavior, which can be used for crude AM pulse width modulation.
+
+				// The period of the noise is determined by this value.
+				// The least significant byte of the LFSR is bitwise ANDed with the AND mask, and then bitwise ORed with the OR mask.
+				if ((++m_noise_value) >= (((unsigned char)(m_rng) & noise_and()) | noise_or())) // Clock the noise value.
+				{
+					m_noise_value = 0;
+
+					// When everything is finally said and done, a 1bit latch is flipped.
+					// This is the final output of the noise, to be multiplied by the tone and envelope generators of the channel.
+					m_noise_out ^= 1;
+
+					noise_rng_tick();
+				}
 			}
+			else if (!m_prescale_noise)
+				noise_rng_tick();
 		}
 
 		for (int chan = 0; chan < NUM_CHANNELS; chan++)
@@ -1129,9 +1115,8 @@ void ay8910_device::sound_stream_update(short** outputs, int outLen)
 			envelope = &m_envelope[chan];
 			if (envelope->holding == 0)
 			{
-				const int period = envelope->period * m_step;
-				envelope->count++;
-				if (envelope->count >= period)
+				const int period = envelope->period * m_env_step_mul;
+				if ((++envelope->count) >= period)
 				{
 					envelope->count = 0;
 					envelope->step--;
@@ -1263,20 +1248,14 @@ void ay8910_device::device_start()
 }
 
 
-void ay8910_device::ay8910_reset_ym(bool ay8930)
+void ay8910_device::ay8910_reset_ym()
 {
 	m_active = false;
 	m_register_latch = 0;
-  if (ay8930) {
-    m_rng = 0x1ffff;
-  } else {
-	  m_rng = 1;
-  }
+	m_rng = (m_feature & PSG_HAS_EXPANDED_MODE) ? 0x1ffff : 1;
 	m_mode = 0; // ay-3-8910 compatible mode
-  m_noise_and = 0xff;
-  m_noise_or = 0;
-  m_noise_value = 0;
-  m_noise_latch = 0;
+	m_noise_value = 0;
+	m_noise_out = 0;
 	for (int chan = 0; chan < NUM_CHANNELS; chan++)
 	{
 		m_tone[chan].reset();
@@ -1335,7 +1314,7 @@ void ay8910_device::ay8910_write_ym(int addr, unsigned char data)
 
 unsigned char ay8910_device::ay8910_read_ym()
 {
-	int r = m_register_latch + get_register_bank();
+	unsigned char r = m_register_latch + get_register_bank();
 
 	if (!m_active) return 0xff; // high impedance
 
@@ -1380,7 +1359,7 @@ unsigned char ay8910_device::ay8910_read_ym()
 
 void ay8910_device::device_reset()
 {
-	ay8910_reset_ym(chip_type == AY8930);
+	ay8910_reset_ym();
 }
 
 /*************************************
@@ -1452,28 +1431,27 @@ ay8910_device::ay8910_device(unsigned int clock)
 }
 
 ay8910_device::ay8910_device(device_type type, unsigned int clock,
-								psg_type_t psg_type, int streams, int ioports, int feature)
+								psg_type_t psg_type, int streams, int ioports, int feature, bool clk_sel)
 	: chip_type(type),
-    m_type(psg_type),
+		m_type(psg_type),
 		m_streams(streams),
 		m_ready(0),
 		m_active(false),
 		m_register_latch(0),
 		m_last_enable(0),
 		m_prescale_noise(0),
+		m_noise_value(0),
 		m_count_noise(0),
 		m_rng(0),
-    m_noise_and(0),
-    m_noise_or(0),
-    m_noise_value(0),
-    m_noise_latch(0),
+		m_noise_out(0),
 		m_mode(0),
 		m_env_step_mask((!(feature & PSG_HAS_EXPANDED_MODE)) && (psg_type == PSG_TYPE_AY) ? 0x0f : 0x1f),
-		m_step(         (feature & PSG_HAS_EXPANDED_MODE) || (psg_type == PSG_TYPE_AY) ? 2 : 1),
+		m_step_mul(    ((feature & PSG_HAS_INTERNAL_DIVIDER) || ((feature & PSG_PIN26_IS_CLKSEL) && clk_sel)) ? 2 : 1),
+		m_env_step_mul(  ((feature & PSG_HAS_EXPANDED_MODE)  || (psg_type == PSG_TYPE_AY)) ? (m_step_mul << 1) : m_step_mul),
 		m_zero_is_off(  (!(feature & PSG_HAS_EXPANDED_MODE)) && (psg_type == PSG_TYPE_AY) ? 1 : 0),
 		m_par(          (!(feature & PSG_HAS_EXPANDED_MODE)) && (psg_type == PSG_TYPE_AY) ? &ay8910_param : &ym2149_param),
 		m_par_env(      (!(feature & PSG_HAS_EXPANDED_MODE)) && (psg_type == PSG_TYPE_AY) ? &ay8910_param : &ym2149_param_env),
-		m_flags(AY8910_LEGACY_OUTPUT),
+		m_flags(AY8910_LEGACY_OUTPUT | (((feature & PSG_PIN26_IS_CLKSEL) && clk_sel) ? YM2149_PIN26_LOW : 0)),
 		m_feature(feature)
 {
 	memset(&m_regs,0,sizeof(m_regs));
@@ -1485,16 +1463,16 @@ ay8910_device::ay8910_device(device_type type, unsigned int clock,
 	m_res_load[0] = m_res_load[1] = m_res_load[2] = 1000; //Default values for resistor loads
 
 	// TODO : measure ay8930 volume parameters (PSG_TYPE_YM for temporary 5 bit handling)
-	set_type((m_feature & PSG_HAS_EXPANDED_MODE) ? PSG_TYPE_YM : psg_type);
+	set_type((m_feature & PSG_HAS_EXPANDED_MODE) ? PSG_TYPE_YM : psg_type, clk_sel);
 }
 
-void ay8910_device::set_type(psg_type_t psg_type)
+void ay8910_device::set_type(psg_type_t psg_type, bool clk_sel)
 {
 	m_type = psg_type;
 	if (psg_type == PSG_TYPE_AY)
 	{
 		m_env_step_mask = 0x0f;
-		m_step = 2;
+		m_env_step_mul = is_clock_divided() ? 4 : 2;
 		m_zero_is_off = 1;
 		m_par = &ay8910_param;
 		m_par_env = &ay8910_param;
@@ -1502,11 +1480,15 @@ void ay8910_device::set_type(psg_type_t psg_type)
 	else
 	{
 		m_env_step_mask = 0x1f;
-		m_step = (m_feature & PSG_HAS_EXPANDED_MODE) ? 2 : 1;
+		m_env_step_mul = is_clock_divided() ? 2 : 1;
 		m_zero_is_off = 0;
 		m_par = &ym2149_param;
 		m_par_env = &ym2149_param_env;
 	}
+	if (m_feature & PSG_HAS_EXPANDED_MODE)
+		m_env_step_mul <<= 1;
+
+	set_clock_sel(clk_sel);
 }
 
 
@@ -1535,24 +1517,24 @@ ay8914_device::ay8914_device(unsigned int clock)
 
 
 
-ay8930_device::ay8930_device(unsigned int clock)
-	: ay8910_device(AY8930, clock, PSG_TYPE_YM, 3, 2, PSG_PIN26_IS_CLKSEL | PSG_HAS_EXPANDED_MODE)
+ay8930_device::ay8930_device(unsigned int clock, bool clk_sel)
+	: ay8910_device(AY8930, clock, PSG_TYPE_YM, 3, 2, PSG_PIN26_IS_CLKSEL | PSG_HAS_EXPANDED_MODE, clk_sel)
 {
 }
 
 
 
 
-ym2149_device::ym2149_device(unsigned int clock)
-	: ay8910_device(YM2149, clock, PSG_TYPE_YM, 3, 2, PSG_PIN26_IS_CLKSEL)
+ym2149_device::ym2149_device(unsigned int clock, bool clk_sel)
+	: ay8910_device(YM2149, clock, PSG_TYPE_YM, 3, 2, PSG_PIN26_IS_CLKSEL, clk_sel)
 {
 }
 
 
 
 
-ym3439_device::ym3439_device(unsigned int clock)
-	: ay8910_device(YM3439, clock, PSG_TYPE_YM, 3, 2, PSG_PIN26_IS_CLKSEL)
+ym3439_device::ym3439_device(unsigned int clock, bool clk_sel)
+	: ay8910_device(YM3439, clock, PSG_TYPE_YM, 3, 2, PSG_PIN26_IS_CLKSEL, clk_sel)
 {
 }
 
diff --git a/src/engine/platform/sound/ay8910.h b/src/engine/platform/sound/ay8910.h
index c9de6da0a..314383f57 100644
--- a/src/engine/platform/sound/ay8910.h
+++ b/src/engine/platform/sound/ay8910.h
@@ -3,6 +3,10 @@
 #ifndef MAME_SOUND_AY8910_H
 #define MAME_SOUND_AY8910_H
 
+#pragma once
+
+#include <algorithm>
+
 #define ALL_8910_CHANNELS -1
 
 /* Internal resistance at Volume level 7. */
@@ -89,7 +93,8 @@ public:
 
 	// configuration helpers
 	void set_flags(int flags) { m_flags = flags; }
-	void set_psg_type(psg_type_t psg_type) { set_type(psg_type); }
+	void set_psg_type(psg_type_t psg_type) { set_type(psg_type, m_flags & YM2149_PIN26_LOW); }
+	void set_psg_type(psg_type_t psg_type, bool clk_sel) { set_type(psg_type, clk_sel); }
 	void set_resistors_load(int res_load0, int res_load1, int res_load2) { m_res_load[0] = res_load0; m_res_load[1] = res_load1; m_res_load[2] = res_load2; }
 
 	unsigned char data_r() { return ay8910_read_ym(); }
@@ -97,7 +102,24 @@ public:
 	void data_w(unsigned char data);
 
 	// /RES
-	void reset_w(unsigned char data = 0) { ay8910_reset_ym(chip_type == AY8930); }
+	void reset_w(unsigned char data = 0) { ay8910_reset_ym(); }
+
+	// Clock select pin
+	void set_clock_sel(bool clk_sel)
+	{
+		if (m_feature & PSG_PIN26_IS_CLKSEL)
+		{
+			if (clk_sel)
+				m_flags |= YM2149_PIN26_LOW;
+			else
+				m_flags &= ~YM2149_PIN26_LOW;
+
+			m_step_mul = is_clock_divided() ? 2 : 1;
+			m_env_step_mul = (!(m_feature & PSG_HAS_EXPANDED_MODE)) && (m_type == PSG_TYPE_AY) ? (m_step_mul << 1) : m_step_mul;
+			if (m_feature & PSG_HAS_EXPANDED_MODE)
+				m_env_step_mul <<= 1;
+		}
+	}
 
 	// use this when BC1 == A0; here, BC1=0 selects 'data' and BC1=1 selects 'latch address'
 	void data_address_w(int offset, unsigned char data) { ay8910_write_ym(~offset & 1, data); } // note that directly connecting BC1 to A0 puts data on 0 and address on 1
@@ -127,7 +149,7 @@ public:
 	// internal interface for PSG component of YM device
 	// FIXME: these should be private, but vector06 accesses them directly
 
-	ay8910_device(device_type type, unsigned int clock, psg_type_t psg_type, int streams, int ioports, int feature = PSG_DEFAULT);
+	ay8910_device(device_type type, unsigned int clock, psg_type_t psg_type, int streams, int ioports, int feature = PSG_DEFAULT, bool clk_sel = false);
 
 	// device-level overrides
 	void device_start();
@@ -138,7 +160,7 @@ public:
 
 	void ay8910_write_ym(int addr, unsigned char data);
 	unsigned char ay8910_read_ym();
-	void ay8910_reset_ym(bool ay8930);
+	void ay8910_reset_ym();
 
 private:
 	static constexpr int NUM_CHANNELS = 3;
@@ -189,7 +211,7 @@ private:
 
 		void reset()
 		{
-			period = 0;
+			period = 1;
 			volume = 0;
 			duty = 0;
 			count = 0;
@@ -199,7 +221,7 @@ private:
 
 		void set_period(unsigned char fine, unsigned char coarse)
 		{
-			period = fine | (coarse << 8);
+			period = std::max<unsigned int>(1, fine | (coarse << 8));
 		}
 
 		void set_volume(unsigned char val)
@@ -223,7 +245,7 @@ private:
 
 		void reset()
 		{
-			period = 0;
+			period = 1;
 			count = 0;
 			step = 0;
 			volume = 0;
@@ -235,7 +257,7 @@ private:
 
 		void set_period(unsigned char fine, unsigned char coarse)
 		{
-			period = fine | (coarse << 8);
+			period = std::max<unsigned int>(1, fine | (coarse << 8));
 		}
 
 		void set_shape(unsigned char shape, unsigned char mask)
@@ -258,6 +280,18 @@ private:
 		}
 	};
 
+	inline void noise_rng_tick()
+	{
+		// The Random Number Generator of the 8910 is a 17-bit shift
+		// register. The input to the shift register is bit0 XOR bit3
+		// (bit0 is the output). This was verified on AY-3-8910 and YM2149 chips.
+
+		if (m_feature & PSG_HAS_EXPANDED_MODE) // AY8930 LFSR algorithm is slightly different, verified from manual
+			m_rng = (m_rng >> 1) | ((BIT(m_rng, 0) ^ BIT(m_rng, 2)) << 16);
+		else
+			m_rng = (m_rng >> 1) | ((BIT(m_rng, 0) ^ BIT(m_rng, 3)) << 16);
+	}
+
 	// inlines
 	inline bool tone_enable(int chan) { return BIT(m_regs[AY_ENABLE], chan); }
 	inline unsigned char tone_volume(tone_t *tone) { return tone->volume & (is_expanded_mode() ? 0x1f : 0x0f); }
@@ -266,14 +300,19 @@ private:
 	inline unsigned char get_envelope_chan(int chan) { return is_expanded_mode() ? chan : 0; }
 
 	inline bool noise_enable(int chan) { return BIT(m_regs[AY_ENABLE], 3 + chan); }
-	inline unsigned char noise_period() { return is_expanded_mode() ? m_regs[AY_NOISEPER] & 0xff : m_regs[AY_NOISEPER] & 0x1f; }
-	inline unsigned char noise_output() { return is_expanded_mode() ? m_noise_latch & 1 : m_rng & 1; }
+	inline unsigned char noise_period() { return std::max<unsigned char>(1, is_expanded_mode() ? (m_regs[AY_NOISEPER] & 0xff) : (m_regs[AY_NOISEPER] & 0x1f)); }
+	inline unsigned char noise_output() { return is_expanded_mode() ? m_noise_out & 1 : m_rng & 1; }
 
 	inline bool is_expanded_mode() { return ((m_feature & PSG_HAS_EXPANDED_MODE) && ((m_mode & 0xe) == 0xa)); }
 	inline unsigned char get_register_bank() { return is_expanded_mode() ? (m_mode & 0x1) << 4 : 0; }
 
+	inline unsigned char noise_and() { return m_regs[AY_NOISEAND] & 0xff; }
+	inline unsigned char noise_or() { return m_regs[AY_NOISEOR] & 0xff; }
+
+	inline bool is_clock_divided() { return ((m_feature & PSG_HAS_INTERNAL_DIVIDER) || ((m_feature & PSG_PIN26_IS_CLKSEL) && (m_flags & YM2149_PIN26_LOW))); }
+
 	// internal helpers
-	void set_type(psg_type_t psg_type);
+	void set_type(psg_type_t psg_type, bool clk_sel);
 	inline float mix_3D();
 	void ay8910_write_reg(int r, int v);
 	void build_mixer_table();
@@ -284,22 +323,21 @@ private:
 	int m_ready;
 	//sound_stream *m_channel;
 	bool m_active;
-	int m_register_latch;
+	unsigned char m_register_latch;
 	unsigned char m_regs[16 * 2];
 	int m_last_enable;
 	tone_t m_tone[NUM_CHANNELS];
 	envelope_t m_envelope[NUM_CHANNELS];
 	unsigned char m_prescale_noise;
-	int m_count_noise;
-	int m_rng;
-  unsigned int m_noise_and;
-  unsigned int m_noise_or;
-  unsigned int m_noise_value;
-  unsigned int m_noise_latch;
+	signed short m_noise_value;
+	signed short m_count_noise;
+	unsigned int m_rng;
+	unsigned char m_noise_out;
 	unsigned char m_mode;
 	unsigned char m_env_step_mask;
 	/* init parameters ... */
-	int m_step;
+	int m_step_mul;
+	int m_env_step_mul;
 	int m_zero_is_off;
 	unsigned char m_vol_enabled[NUM_CHANNELS];
 	const ay_ym_param *m_par;
@@ -337,19 +375,19 @@ public:
 class ay8930_device : public ay8910_device
 {
 public:
-	ay8930_device(unsigned int clock);
+	ay8930_device(unsigned int clock, bool clk_sel = false);
 };
 
 class ym2149_device : public ay8910_device
 {
 public:
-	ym2149_device(unsigned int clock);
+	ym2149_device(unsigned int clock, bool clk_sel = false);
 };
 
 class ym3439_device : public ay8910_device
 {
 public:
-	ym3439_device(unsigned int clock);
+	ym3439_device(unsigned int clock, bool clk_sel = false);
 };
 
 class ymz284_device : public ay8910_device
diff --git a/src/engine/platform/ym2203ext.cpp b/src/engine/platform/ym2203ext.cpp
index 7948d51e7..9ca77e9fc 100644
--- a/src/engine/platform/ym2203ext.cpp
+++ b/src/engine/platform/ym2203ext.cpp
@@ -463,27 +463,17 @@ void DivPlatformYM2203Ext::muteChannel(int ch, bool mute) {
 }
 
 void DivPlatformYM2203Ext::forceIns() {
-  for (int i=0; i<6; i++) {
+  for (int i=0; i<3; i++) {
     for (int j=0; j<4; j++) {
       unsigned short baseAddr=chanOffs[i]|opOffs[j];
       DivInstrumentFM::Operator& op=chan[i].state.op[j];
-      if (i==2) { // extended channel
-        if (isOpMuted[j]) {
-          rWrite(baseAddr+0x40,127);
-        } else if (isOutput[chan[i].state.alg][j]) {
-          rWrite(baseAddr+0x40,127-(((127-op.tl)*(opChan[j].vol&0x7f))/127));
-        } else {
-          rWrite(baseAddr+0x40,op.tl);
-        }
+      if (isMuted[i]) {
+        rWrite(baseAddr+ADDR_TL,127);
       } else {
-        if (isMuted[i]) {
-          rWrite(baseAddr+ADDR_TL,127);
+        if (isOutput[chan[i].state.alg][j]) {
+          rWrite(baseAddr+ADDR_TL,127-(((127-op.tl)*(chan[i].outVol&0x7f))/127));
         } else {
-          if (isOutput[chan[i].state.alg][j]) {
-            rWrite(baseAddr+ADDR_TL,127-(((127-op.tl)*(chan[i].outVol&0x7f))/127));
-          } else {
-            rWrite(baseAddr+ADDR_TL,op.tl);
-          }
+          rWrite(baseAddr+ADDR_TL,op.tl);
         }
       }
       rWrite(baseAddr+ADDR_MULT_DT,(op.mult&15)|(dtTable[op.dt&7]<<4));
@@ -499,9 +489,10 @@ void DivPlatformYM2203Ext::forceIns() {
       chan[i].freqChanged=true;
     }
   }
-  for (int i=6; i<16; i++) {
+  for (int i=3; i<6; i++) {
     chan[i].insChanged=true;
   }
+
   ay->forceIns();
   ay->flushWrites();
   for (DivRegWrite& i: ay->getRegisterWrites()) {
diff --git a/src/engine/platform/ym2608.cpp b/src/engine/platform/ym2608.cpp
index 236e6a087..b7e18e69d 100644
--- a/src/engine/platform/ym2608.cpp
+++ b/src/engine/platform/ym2608.cpp
@@ -1405,7 +1405,7 @@ const void* DivPlatformYM2608::getSampleMem(int index) {
 }
 
 size_t DivPlatformYM2608::getSampleMemCapacity(int index) {
-  return index == 0 ? 2097152 : 0;
+  return index == 0 ? 262144 : 0;
 }
 
 size_t DivPlatformYM2608::getSampleMemUsage(int index) {
diff --git a/src/engine/platform/ym2608Interface.cpp b/src/engine/platform/ym2608Interface.cpp
index 62cd8899f..242721f09 100644
--- a/src/engine/platform/ym2608Interface.cpp
+++ b/src/engine/platform/ym2608Interface.cpp
@@ -31,7 +31,7 @@ uint8_t DivYM2608Interface::ymfm_external_read(ymfm::access_class type, uint32_t
       if (adpcmBMem==NULL) {
         return 0;
       }
-      return adpcmBMem[address&0xffffff];
+      return adpcmBMem[address&0x3ffff];
     default:
       return 0;
   }
diff --git a/src/engine/song.h b/src/engine/song.h
index 219225e8f..60a0e56d9 100644
--- a/src/engine/song.h
+++ b/src/engine/song.h
@@ -262,13 +262,19 @@ struct DivSong {
   //     - 8: 0.83MHz (Sunsoft 5B on PAL)
   //     - 9: 1.10MHz (Gamate/VIC-20 PAL)
   //     - 10: 2.097152MHz (Game Boy)
+  //     - 11: 3.58MHz (Darky)
+  //     - 12: 3.6MHz (Darky)
   //   - bit 4-5: chip type (ignored on AY8930)
   //     - 0: AY-3-8910 or similar
   //     - 1: YM2149
   //     - 2: Sunsoft 5B
-  //   - bit 6: stereo
+  //     - 3: AY-3-8914
+  //   - bit 6: stereo (ignored on Sunsoft 5B)
   //     - 0: mono
   //     - 1: stereo ABC
+  //   - bit 7: clock divider pin (YM2149, AY8930)
+  //     - 0: high (disable divider)
+  //     - 1: low (internally divided to half)
   // - SAA1099:
   //   - bit 0-1: clock rate
   //     - 0: 8MHz (SAM Coupé, Game Blaster)
diff --git a/src/engine/vgmOps.cpp b/src/engine/vgmOps.cpp
index 53eddc1b2..2916c1034 100644
--- a/src/engine/vgmOps.cpp
+++ b/src/engine/vgmOps.cpp
@@ -906,11 +906,41 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version) {
         }
         break;
       case DIV_SYSTEM_AY8910:
-      case DIV_SYSTEM_AY8930:
+      case DIV_SYSTEM_AY8930: {
         if (!hasAY) {
+          bool hasClockDivider=false; // Configurable clock divider
+          bool hasStereo=true; // Stereo
           hasAY=disCont[i].dispatch->chipClock;
-          ayConfig=(song.system[i]==DIV_SYSTEM_AY8930)?3:0;
           ayFlags=1;
+          if (song.system[i]==DIV_SYSTEM_AY8930) { // AY8930
+            ayConfig=0x03;
+            hasClockDivider=true;
+          } else {
+            switch ((song.systemFlags[i]>>4)&3) {
+              default:
+              case 0: // AY8910
+                ayConfig=0x00;
+                break;
+              case 1: // YM2149
+                ayConfig=0x10;
+                hasClockDivider=true;
+                break;
+              case 2: // Sunsoft 5B
+                ayConfig=0x10;
+                ayFlags|=0x12; // Clock internally divided, Single sound output
+                hasStereo=false; // due to above, can't be per-channel stereo configurable
+                break;
+              case 3: // AY8914
+                ayConfig=0x04;
+                break;
+            }
+          }
+          if (hasClockDivider && ((song.systemFlags[i]>>7)&1)) {
+            ayFlags|=0x10;
+          }
+          if (hasStereo && ((song.systemFlags[i]>>6)&1)) {
+            ayFlags|=0x80;
+          }
           willExport[i]=true;
         } else if (!(hasAY&0x40000000)) {
           isSecond[i]=true;
@@ -919,6 +949,7 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop, int version) {
           howManyChips++;
         }
         break;
+      }
       case DIV_SYSTEM_SAA1099:
         if (!hasSAA) {
           hasSAA=disCont[i].dispatch->chipClock;
diff --git a/src/gui/about.cpp b/src/gui/about.cpp
index ce543f5f4..76fc80ad2 100644
--- a/src/gui/about.cpp
+++ b/src/gui/about.cpp
@@ -91,7 +91,7 @@ const char* aboutLine[]={
   "ymfm by Aaron Giles",
   "MAME SN76496 by Nicola Salmoria",
   "MAME AY-3-8910 by Couriersud",
-  "with AY8930 fixes by Eulous",
+  "with AY8930 fixes by Eulous, cam900 and Grauw",
   "MAME SAA1099 by Juergen Buchmueller and Manuel Abadia",
   "SAASound by Dave Hooper and Simon Owen",
   "SameBoy by Lior Halphon",
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index ec38c86c2..55eab2af5 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -2794,6 +2794,7 @@ bool FurnaceGUI::loop() {
     }
     if (ImGui::BeginMenu("window")) {
       if (ImGui::MenuItem("song information",BIND_FOR(GUI_ACTION_WINDOW_SONG_INFO),songInfoOpen)) songInfoOpen=!songInfoOpen;
+      if (ImGui::MenuItem("subsongs",BIND_FOR(GUI_ACTION_WINDOW_SUBSONGS),subSongsOpen)) subSongsOpen=!subSongsOpen;
       if (ImGui::MenuItem("instruments",BIND_FOR(GUI_ACTION_WINDOW_INS_LIST),insListOpen)) insListOpen=!insListOpen;
       if (ImGui::MenuItem("wavetables",BIND_FOR(GUI_ACTION_WINDOW_WAVE_LIST),waveListOpen)) waveListOpen=!waveListOpen;
       if (ImGui::MenuItem("samples",BIND_FOR(GUI_ACTION_WINDOW_SAMPLE_LIST),sampleListOpen)) sampleListOpen=!sampleListOpen;
diff --git a/src/gui/presets.cpp b/src/gui/presets.cpp
index 56ac54a69..d04d329d7 100644
--- a/src/gui/presets.cpp
+++ b/src/gui/presets.cpp
@@ -461,7 +461,7 @@ void FurnaceGUI::initSystemPresets() {
   cat.systems.push_back(FurnaceGUISysDef(
     "NES with Sunsoft 5B", {
       DIV_SYSTEM_NES, 64, 0, 0,
-      DIV_SYSTEM_AY8910, 64, 0, 38,
+      DIV_SYSTEM_AY8910, 64, 0, 32,
       0
     }
   ));
@@ -643,6 +643,15 @@ void FurnaceGUI::initSystemPresets() {
       0
     }
   ));
+  cat.systems.push_back(FurnaceGUISysDef(
+    "MSX + Darky", {
+      DIV_SYSTEM_AY8910, 64, 0, 16,
+      DIV_SYSTEM_AY8930, 64, 0, 139, // 3.58MHz
+      DIV_SYSTEM_AY8930, 64, 0, 139, // 3.58MHz or 3.6MHz selectable via register
+      // per-channel mixer (soft panning, post processing) isn't emulated at all
+      0
+    }
+  ));
   cat.systems.push_back(FurnaceGUISysDef(
     "MSX + SCC", {
       DIV_SYSTEM_AY8910, 64, 0, 16,
diff --git a/src/gui/subSongs.cpp b/src/gui/subSongs.cpp
index 21b15001f..192cdb9d3 100644
--- a/src/gui/subSongs.cpp
+++ b/src/gui/subSongs.cpp
@@ -9,7 +9,7 @@ void FurnaceGUI::drawSubSongs() {
     ImGui::SetNextWindowFocus();
     nextWindow=GUI_WINDOW_NOTHING;
   }
-  if (!oscOpen) return;
+  if (!subSongsOpen) return;
   ImGui::SetNextWindowSizeConstraints(ImVec2(64.0f*dpiScale,32.0f*dpiScale),ImVec2(scrW*dpiScale,scrH*dpiScale));
   if (ImGui::Begin("Subsongs",&subSongsOpen,ImGuiWindowFlags_NoScrollWithMouse|ImGuiWindowFlags_NoScrollbar)) {
     char id[1024];
diff --git a/src/gui/sysConf.cpp b/src/gui/sysConf.cpp
index 9ac2e4bd9..e70348454 100644
--- a/src/gui/sysConf.cpp
+++ b/src/gui/sysConf.cpp
@@ -200,7 +200,7 @@ void FurnaceGUI::drawSysConf(int chan, DivSystem type, unsigned int& flags, bool
         copyOfFlags=(flags&(~15))|5;
         
       }
-      if (ImGui::RadioButton("0.89MHz (Sunsoft 5B)",(flags&15)==6)) {
+      if (ImGui::RadioButton("0.89MHz (Pre-divided Sunsoft 5B)",(flags&15)==6)) {
         copyOfFlags=(flags&(~15))|6;
         
       }
@@ -208,7 +208,7 @@ void FurnaceGUI::drawSysConf(int chan, DivSystem type, unsigned int& flags, bool
         copyOfFlags=(flags&(~15))|7;
         
       }
-      if (ImGui::RadioButton("0.83MHz (Sunsoft 5B on PAL)",(flags&15)==8)) {
+      if (ImGui::RadioButton("0.83MHz (Pre-divided Sunsoft 5B on PAL)",(flags&15)==8)) {
         copyOfFlags=(flags&(~15))|8;
         
       }
@@ -219,6 +219,14 @@ void FurnaceGUI::drawSysConf(int chan, DivSystem type, unsigned int& flags, bool
       if (ImGui::RadioButton("2^21Hz (Game Boy)",(flags&15)==10)) {
         copyOfFlags=(flags&(~15))|10;
         
+      }
+      if (ImGui::RadioButton("3.58MHz (Darky)",(flags&15)==11)) {
+        copyOfFlags=(flags&(~15))|11;
+        
+      }
+      if (ImGui::RadioButton("3.6MHz (Darky)",(flags&15)==12)) {
+        copyOfFlags=(flags&(~15))|12;
+        
       }
       if (type==DIV_SYSTEM_AY8910) {
         ImGui::Text("Chip type:");
@@ -240,10 +248,17 @@ void FurnaceGUI::drawSysConf(int chan, DivSystem type, unsigned int& flags, bool
         }
       }
       bool stereo=flags&0x40;
-      ImGui::BeginDisabled((flags&0x30)==32);
+      ImGui::BeginDisabled((type==DIV_SYSTEM_AY8910) && ((flags&0x30)==32));
       if (ImGui::Checkbox("Stereo##_AY_STEREO",&stereo)) {
         copyOfFlags=(flags&(~0x40))|(stereo?0x40:0);
         
+      }
+      ImGui::EndDisabled();
+      bool clockSel=flags&0x80;
+      ImGui::BeginDisabled((type==DIV_SYSTEM_AY8910) && ((flags&0x30)!=16));
+      if (ImGui::Checkbox("Half Clock divider##_AY_CLKSEL",&clockSel)) {
+        copyOfFlags=(flags&(~0x80))|(clockSel?0x80:0);
+        
       }
       ImGui::EndDisabled();
       break;