diff --git a/demos/bruno_time.fur b/demos/bruno_time.fur
index 7905bed61..351a6e1f9 100644
Binary files a/demos/bruno_time.fur and b/demos/bruno_time.fur differ
diff --git a/papers/format.md b/papers/format.md
index a9b7166bb..e17345119 100644
--- a/papers/format.md
+++ b/papers/format.md
@@ -69,7 +69,8 @@ size | description
  128 | sound chip parameters (TODO)
  ??? | song name
  ??? | song author
- 24  | reserved for compatibility flags
+  4f | A-4 tuning
+ 20  | reserved
  4?? | pointers to instruments
  4?? | pointers to wavetables
  4?? | pointers to samples
diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index 953f0fc74..7f62a886e 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -144,6 +144,11 @@ class DivDispatch {
      * the engine shall resample to the output rate.
      */
     int rate;
+    
+    /**
+     * the actual chip's clock.
+     */
+    int chipClock;
 
     /**
      * fill a buffer with sound data.
@@ -288,4 +293,11 @@ class DivDispatch {
 
      virtual ~DivDispatch();
 };
+
+#define NOTE_PERIODIC(x) parent->calcBaseFreq(chipClock,CHIP_DIVIDER,x,true)
+#define NOTE_FREQUENCY(x) parent->calcBaseFreq(chipClock,CHIP_FREQBASE,x,false)
+
+#define COLOR_NTSC (315000000.0/88.0)
+#define COLOR_PAL (283.75*15625.0+25.0)
+
 #endif
diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 6fdc39444..7156f1d2f 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -1355,8 +1355,14 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     ds.author=reader.readString();
     logI("%s by %s\n",ds.name.c_str(),ds.author.c_str());
 
+    if (ds.version>=33) {
+      ds.tuning=reader.readF();
+    } else {
+      reader.readI();
+    }
+
     // reserved
-    for (int i=0; i<24; i++) reader.readC();
+    for (int i=0; i<20; i++) reader.readC();
 
     // pointers
     reader.read(insPtr,ds.insLen*4);
@@ -1699,9 +1705,11 @@ SafeWriter* DivEngine::saveFur() {
   w->writeString(song.name,false);
   // song author
   w->writeString(song.author,false);
+
+  w->writeF(song.tuning);
   
   // reserved
-  for (int i=0; i<24; i++) {
+  for (int i=0; i<20; i++) {
     w->writeC(0);
   }
 
@@ -3886,6 +3894,13 @@ void DivEngine::playSub(bool preserveDrift) {
   }
 }
 
+int DivEngine::calcBaseFreq(double clock, double divider, int note, bool period) {
+  double base=(period?(song.tuning*0.0625):song.tuning)*pow(2.0,(float)(note+3)/12.0);
+  return period?
+         round((clock/base)/divider):
+         base*(divider/clock);
+}
+
 int DivEngine::calcFreq(int base, int pitch, bool period) {
   return period?
           int(base*pow(2,-(double)pitch/(12.0*128.0))/(98.0+globalPitch*6.0)*98.0):
@@ -4014,7 +4029,7 @@ void DivEngine::previewSample(int sample, int note) {
   blip_clear(samp_bb);
   double rate=song.sample[sample]->rate;
   if (note>=0) {
-    rate=(440.0*pow(2.0,(double)(note+3)/12.0));
+    rate=(song.tuning*pow(2.0,(double)(note+3)/12.0));
     if (rate<=0) rate=song.sample[sample]->rate;
   }
   blip_set_rates(samp_bb,rate,got.rate);
@@ -4045,7 +4060,7 @@ void DivEngine::previewWave(int wave, int note) {
     return;
   }
   blip_clear(samp_bb);
-  blip_set_rates(samp_bb,song.wave[wave]->len*(27.5*pow(2.0,(double)(note+3)/12.0)),got.rate);
+  blip_set_rates(samp_bb,song.wave[wave]->len*((song.tuning*0.0625)*pow(2.0,(double)(note+3)/12.0)),got.rate);
   samp_prevSample=0;
   sPreview.pos=0;
   sPreview.sample=-1;
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 3cdef106d..a0ff5678c 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -11,8 +11,8 @@
 #include <map>
 #include <queue>
 
-#define DIV_VERSION "0.5pre3"
-#define DIV_ENGINE_VERSION 32
+#define DIV_VERSION "0.5pre4"
+#define DIV_ENGINE_VERSION 33
 
 enum DivStatusView {
   DIV_STATUS_NOTHING=0,
@@ -260,6 +260,9 @@ class DivEngine {
     void setConf(String key, double value);
     void setConf(String key, String value);
 
+    // calculate base frequency/period
+    int calcBaseFreq(double clock, double divider, int note, bool period);
+
     // calculate frequency/period
     int calcFreq(int base, int pitch, bool period=false);
 
diff --git a/src/engine/platform/amiga.cpp b/src/engine/platform/amiga.cpp
index 80a06483a..6ed9f6c84 100644
--- a/src/engine/platform/amiga.cpp
+++ b/src/engine/platform/amiga.cpp
@@ -2,8 +2,8 @@
 #include "../engine.h"
 #include <math.h>
 
-#define FREQ_BASE 6843.0f
 #define AMIGA_DIVIDER 8
+#define CHIP_DIVIDER 16
 
 void DivPlatformAmiga::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   for (size_t h=start; h<start+len; h++) {
@@ -58,15 +58,15 @@ void DivPlatformAmiga::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
         } else {
-          chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -100,7 +100,7 @@ int DivPlatformAmiga::dispatch(DivCommand c) {
     case DIV_CMD_NOTE_ON: {
       DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+        chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
       }
       chan[c.chan].sample=ins->amiga.initSample;
       if (chan[c.chan].sample<0 || chan[c.chan].sample>=parent->song.sampleLen) {
@@ -151,7 +151,7 @@ int DivPlatformAmiga::dispatch(DivCommand c) {
       chan[c.chan].keyOn=true;
       break;
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_PERIODIC(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -174,7 +174,7 @@ int DivPlatformAmiga::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_LEGATO:
-      chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp-12):(0)))/12.0f)));
+      chan[c.chan].baseFreq=NOTE_PERIODIC(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp-12):(0)));
       chan[c.chan].freqChanged=true;
       chan[c.chan].note=c.value;
       break;
@@ -243,10 +243,11 @@ void DivPlatformAmiga::notifyInsDeletion(void* ins) {
 
 void DivPlatformAmiga::setPAL(bool pal) {
   if (pal) {
-    rate=3546895/AMIGA_DIVIDER;
+    chipClock=COLOR_PAL*4.0/5.0;
   } else {
-    rate=3579545/AMIGA_DIVIDER;
+    chipClock=COLOR_NTSC;
   }
+  rate=chipClock/AMIGA_DIVIDER;
 }
 
 int DivPlatformAmiga::init(DivEngine* p, int channels, int sugRate, bool pal) {
diff --git a/src/engine/platform/arcade.cpp b/src/engine/platform/arcade.cpp
index 43e3090a6..2823f32fe 100644
--- a/src/engine/platform/arcade.cpp
+++ b/src/engine/platform/arcade.cpp
@@ -330,7 +330,7 @@ void DivPlatformArcade::tick() {
     if (chan[i].freqChanged) {
       chan[i].freq=chan[i].baseFreq+(chan[i].pitch>>1)-64;
       if (chan[i].furnacePCM) {
-        chan[i].pcm.freq=MIN(255,((440.0*pow(2.0,double(chan[i].freq+256)/(64.0*12.0)))*255)/31250);
+        chan[i].pcm.freq=MIN(255,((parent->song.tuning*pow(2.0,double(chan[i].freq+256)/(64.0*12.0)))*255)/31250);
         if (dumpWrites && i>=8) {
           addWrite(0x10007+((i-8)<<3),chan[i].pcm.freq);
         }
diff --git a/src/engine/platform/ay.cpp b/src/engine/platform/ay.cpp
index 4bc3328ff..0a422f144 100644
--- a/src/engine/platform/ay.cpp
+++ b/src/engine/platform/ay.cpp
@@ -7,7 +7,7 @@
 #define rWrite(a,v) if (!skipRegisterWrites) {pendingWrites[a]=v;}
 #define immWrite(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
 
-#define PSG_FREQ_BASE 6848.0f
+#define CHIP_DIVIDER 8
 
 void DivPlatformAY8910::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   if (ayBufLen<len) {
@@ -45,15 +45,15 @@ void DivPlatformAY8910::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
         } else {
-          chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -146,7 +146,7 @@ int DivPlatformAY8910::dispatch(DivCommand c) {
     case DIV_CMD_NOTE_ON: {
       DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+        chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
       }
@@ -193,7 +193,7 @@ int DivPlatformAY8910::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_PERIODIC(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -216,7 +216,7 @@ int DivPlatformAY8910::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_LEGATO: {
-      chan[c.chan].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+      chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
       chan[c.chan].freqChanged=true;
       break;
     }
@@ -357,10 +357,11 @@ void DivPlatformAY8910::notifyInsDeletion(void* ins) {
 
 void DivPlatformAY8910::setPAL(bool pal) {
   if (pal) {
-    rate=221681;
+    chipClock=COLOR_PAL*2.0/5.0;
   } else {
-    rate=223722;
+    chipClock=COLOR_NTSC/2.0;
   }
+  rate=chipClock/8;
 }
 
 int DivPlatformAY8910::init(DivEngine* p, int channels, int sugRate, bool pal) {
diff --git a/src/engine/platform/ay8930.cpp b/src/engine/platform/ay8930.cpp
index 5641c7a5d..bdae663c0 100644
--- a/src/engine/platform/ay8930.cpp
+++ b/src/engine/platform/ay8930.cpp
@@ -7,7 +7,7 @@
 #define rWrite(a,v) if (!skipRegisterWrites) {pendingWrites[a]=v;}
 #define immWrite(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
 
-#define PSG_FREQ_BASE 6848.0f
+#define CHIP_DIVIDER 8
 
 void DivPlatformAY8930::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   if (ayBufLen<len) {
@@ -66,15 +66,15 @@ void DivPlatformAY8930::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
         } else {
-          chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -172,7 +172,7 @@ int DivPlatformAY8930::dispatch(DivCommand c) {
     case DIV_CMD_NOTE_ON: {
       DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+        chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
       }
@@ -220,7 +220,7 @@ int DivPlatformAY8930::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_PERIODIC(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -243,7 +243,7 @@ int DivPlatformAY8930::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_LEGATO: {
-      chan[c.chan].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+      chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
       chan[c.chan].freqChanged=true;
       break;
     }
@@ -392,10 +392,11 @@ void DivPlatformAY8930::notifyInsDeletion(void* ins) {
 
 void DivPlatformAY8930::setPAL(bool pal) {
   if (pal) {
-    rate=221681;
+    chipClock=COLOR_PAL*2.0/5.0;
   } else {
-    rate=223722;
+    chipClock=COLOR_NTSC/2.0;
   }
+  rate=chipClock/8;
 }
 
 int DivPlatformAY8930::init(DivEngine* p, int channels, int sugRate, bool pal) {
diff --git a/src/engine/platform/c64.cpp b/src/engine/platform/c64.cpp
index b5760a3a5..b86ed32b5 100644
--- a/src/engine/platform/c64.cpp
+++ b/src/engine/platform/c64.cpp
@@ -2,10 +2,10 @@
 #include "../engine.h"
 #include <math.h>
 
-#define FREQ_BASE 277.0f
-
 #define rWrite(a,v) if (!skipRegisterWrites) {sid.write(a,v); if (dumpWrites) {addWrite(a,v);} }
 
+#define CHIP_FREQBASE 524288
+
 void DivPlatformC64::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   for (size_t i=start; i<start+len; i++) {
     sid.clock();
@@ -42,15 +42,15 @@ void DivPlatformC64::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=round(FREQ_BASE*pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_FREQUENCY(chan[i].std.arp);
         } else {
-          chan[i].baseFreq=round(FREQ_BASE*pow(2.0f,((float)(chan[i].note+(signed char)chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_FREQUENCY(chan[i].note+(signed char)chan[i].std.arp);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(FREQ_BASE*pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_FREQUENCY(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -104,7 +104,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
     case DIV_CMD_NOTE_ON: {
       DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=round(FREQ_BASE*pow(2.0f,((float)c.value/12.0f)));
+        chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
       }
@@ -170,7 +170,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
       chan[c.chan].freqChanged=true;
       break;
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(FREQ_BASE*pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_FREQUENCY(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -207,7 +207,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
       rWrite(c.chan*7+4,(chan[c.chan].wave<<4)|(chan[c.chan].ring<<2)|(chan[c.chan].sync<<1)|chan[c.chan].active);
       break;
     case DIV_CMD_LEGATO:
-      chan[c.chan].baseFreq=round(FREQ_BASE*pow(2.0f,((float)(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)))/12.0f)));
+      chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)));
       chan[c.chan].freqChanged=true;
       chan[c.chan].note=c.value;
       break;
@@ -357,10 +357,11 @@ void DivPlatformC64::setChipModel(bool is6581) {
 
 void DivPlatformC64::setPAL(bool pal) {
   if (pal) {
-    rate=985248;
+    rate=COLOR_PAL*2.0/9.0;
   } else {
-    rate=1022727;
+    rate=COLOR_NTSC*2.0/7.0;
   }
+  chipClock=rate;
 }
 
 int DivPlatformC64::init(DivEngine* p, int channels, int sugRate, bool pal) {
diff --git a/src/engine/platform/gb.cpp b/src/engine/platform/gb.cpp
index 702139f30..069150b4c 100644
--- a/src/engine/platform/gb.cpp
+++ b/src/engine/platform/gb.cpp
@@ -5,7 +5,7 @@
 #define rWrite(a,v) if (!skipRegisterWrites) {GB_apu_write(gb,a,v); if (dumpWrites) {addWrite(a,v);} }
 #define immWrite(a,v) {GB_apu_write(gb,a,v); if (dumpWrites) {addWrite(a,v);} }
 
-#define FREQ_BASE 8015.85f
+#define CHIP_DIVIDER 16
 
 void DivPlatformGB::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   for (size_t i=start; i<start+len; i++) {
@@ -91,16 +91,16 @@ void DivPlatformGB::tick() {
       } else {
         if (!chan[i].inPorta) {
           if (chan[i].std.arpMode) {
-            chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp+24)/12.0f)));
+            chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp+24);
           } else {
-            chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+            chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
           }
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -181,7 +181,7 @@ int DivPlatformGB::dispatch(DivCommand c) {
         if (c.chan==3) { // noise
           chan[c.chan].baseFreq=c.value;
         } else {
-          chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+          chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
         }
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
@@ -223,7 +223,7 @@ int DivPlatformGB::dispatch(DivCommand c) {
       chan[c.chan].keyOn=true;
       break;
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_PERIODIC(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -261,7 +261,7 @@ int DivPlatformGB::dispatch(DivCommand c) {
     }
     case DIV_CMD_LEGATO:
       if (c.chan==3) break;
-      chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)))/12.0f)));
+      chan[c.chan].baseFreq=NOTE_PERIODIC(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)));
       chan[c.chan].freqChanged=true;
       chan[c.chan].note=c.value;
       break;
@@ -356,7 +356,8 @@ int DivPlatformGB::init(DivEngine* p, int channels, int sugRate, bool pal) {
   parent=p;
   dumpWrites=false;
   skipRegisterWrites=false;
-  rate=262144;
+  chipClock=4194304;
+  rate=chipClock/16;
   gb=new GB_gameboy_t;
   reset();
   return 4;
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index d45205778..28667ebee 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -9,6 +9,8 @@ static unsigned char konOffs[6]={
   0, 1, 2, 4, 5, 6
 };
 
+#define CHIP_FREQBASE 9440540
+
 void DivPlatformGenesis::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   static short o[2];
   static int os[2];
@@ -104,15 +106,15 @@ void DivPlatformGenesis::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=644.0f*pow(2.0f,((float)chan[i].std.arp/12.0f));
+          chan[i].baseFreq=NOTE_FREQUENCY(chan[i].std.arp);
         } else {
-          chan[i].baseFreq=644.0f*pow(2.0f,((float)(chan[i].note+(signed char)chan[i].std.arp)/12.0f));
+          chan[i].baseFreq=NOTE_FREQUENCY(chan[i].note+(signed char)chan[i].std.arp);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=644.0f*pow(2.0f,((float)chan[i].note/12.0f));
+        chan[i].baseFreq=NOTE_FREQUENCY(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -307,7 +309,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
           }
           dacPos=0;
           dacPeriod=0;
-          chan[c.chan].baseFreq=644.0f*pow(2.0f,((float)c.value/12.0f));
+          chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
           chan[c.chan].freqChanged=true;
           chan[c.chan].furnaceDac=true;
         } else { // compatible mode
@@ -365,7 +367,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       chan[c.chan].insChanged=false;
 
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=644.0f*pow(2.0f,((float)c.value/12.0f));
+        chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
         chan[c.chan].note=c.value;
         chan[c.chan].freqChanged=true;
       }
@@ -428,7 +430,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=644.0f*pow(2.0f,((float)c.value2/12.0f));
+      int destFreq=NOTE_FREQUENCY(c.value2);
       int newFreq;
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
@@ -471,7 +473,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       }
       break;
     case DIV_CMD_LEGATO: {
-      chan[c.chan].baseFreq=644.0f*pow(2.0f,((float)c.value/12.0f));
+      chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
       chan[c.chan].note=c.value;
       chan[c.chan].freqChanged=true;
       break;
@@ -638,10 +640,12 @@ void DivPlatformGenesis::notifyInsDeletion(void* ins) {
 
 void DivPlatformGenesis::setPAL(bool pal) {
   if (pal) {
-    rate=211125;
+    chipClock=COLOR_PAL*12.0/7.0;
   } else {
-    rate=213068;
+    chipClock=COLOR_NTSC*15.0/7.0;
   }
+  psg.setPAL(pal);
+  rate=chipClock/36;
 }
 
 int DivPlatformGenesis::init(DivEngine* p, int channels, int sugRate, bool pal) {
diff --git a/src/engine/platform/genesisext.cpp b/src/engine/platform/genesisext.cpp
index 7f354d452..078ca38bf 100644
--- a/src/engine/platform/genesisext.cpp
+++ b/src/engine/platform/genesisext.cpp
@@ -4,6 +4,8 @@
 
 #include "genesisshared.h"
 
+#define CHIP_FREQBASE 9440540
+
 int DivPlatformGenesisExt::dispatch(DivCommand c) {
   if (c.chan<2) {
     return DivPlatformGenesis::dispatch(c);
@@ -54,7 +56,7 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
       opChan[ch].insChanged=false;
 
       if (c.value!=DIV_NOTE_NULL) {
-        opChan[ch].baseFreq=644.0f*pow(2.0f,((float)c.value/12.0f));
+        opChan[ch].baseFreq=NOTE_FREQUENCY(c.value);
         opChan[ch].freqChanged=true;
       }
       opChan[ch].keyOn=true;
@@ -108,7 +110,7 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=644.0f*pow(2.0f,((float)c.value2/12.0f));
+      int destFreq=NOTE_FREQUENCY(c.value2);
       int newFreq;
       bool return2=false;
       if (destFreq>opChan[ch].baseFreq) {
@@ -141,7 +143,7 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_LEGATO: {
-      opChan[ch].baseFreq=644.0f*pow(2.0f,((float)c.value/12.0f));
+      opChan[ch].baseFreq=NOTE_FREQUENCY(c.value);
       opChan[ch].freqChanged=true;
       break;
     }
diff --git a/src/engine/platform/nes.cpp b/src/engine/platform/nes.cpp
index e5c8c8673..a02a72b62 100644
--- a/src/engine/platform/nes.cpp
+++ b/src/engine/platform/nes.cpp
@@ -4,8 +4,7 @@
 #include <cstddef>
 #include <math.h>
 
-#define FREQ_BASE 3424.0f
-#define FREQ_BASE_PAL 3180.0f
+#define CHIP_DIVIDER 16
 
 #define rWrite(a,v) if (!skipRegisterWrites) {apu_wr_reg(nes,a,v); if (dumpWrites) {addWrite(a,v);} }
 
@@ -97,16 +96,16 @@ void DivPlatformNES::tick() {
       } else {
         if (!chan[i].inPorta) {
           if (chan[i].std.arpMode) {
-            chan[i].baseFreq=round(freqBase/pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+            chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
           } else {
-            chan[i].baseFreq=round(freqBase/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+            chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
           }
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(freqBase/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -190,7 +189,7 @@ int DivPlatformNES::dispatch(DivCommand c) {
           }
           dacPos=0;
           dacPeriod=0;
-          chan[c.chan].baseFreq=440.0f*pow(2.0f,((float)(c.value+3)/12.0f));
+          chan[c.chan].baseFreq=parent->song.tuning*pow(2.0f,((float)(c.value+3)/12.0f));
           if (c.value!=DIV_NOTE_NULL) {
             chan[c.chan].freqChanged=true;
             chan[c.chan].note=c.value;
@@ -220,7 +219,7 @@ int DivPlatformNES::dispatch(DivCommand c) {
         }
       } else {
         if (c.value!=DIV_NOTE_NULL) {
-          chan[c.chan].baseFreq=round(freqBase/pow(2.0f,((float)c.value/12.0f)));
+          chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
         }
       }
       if (c.value!=DIV_NOTE_NULL) {
@@ -273,7 +272,7 @@ int DivPlatformNES::dispatch(DivCommand c) {
       chan[c.chan].freqChanged=true;
       break;
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(freqBase/pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_PERIODIC(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -309,7 +308,7 @@ int DivPlatformNES::dispatch(DivCommand c) {
       break;
     case DIV_CMD_LEGATO:
       if (c.chan==3) break;
-      chan[c.chan].baseFreq=round(freqBase/pow(2.0f,((float)(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)))/12.0f)));
+      chan[c.chan].baseFreq=NOTE_PERIODIC(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)));
       chan[c.chan].freqChanged=true;
       chan[c.chan].note=c.value;
       break;
@@ -377,16 +376,15 @@ bool DivPlatformNES::keyOffAffectsArp(int ch) {
 
 void DivPlatformNES::setPAL(bool pal) {
   if (pal) {
-    rate=1662607;
-    freqBase=FREQ_BASE_PAL;
+    rate=COLOR_PAL*3.0/8.0;
     apuType=1;
     nes->apu.type=apuType;
   } else {
-    rate=1789773;
-    freqBase=FREQ_BASE;
+    rate=COLOR_NTSC/2.0;
     apuType=0;
     nes->apu.type=apuType;
   }
+  chipClock=rate;
 }
 
 void DivPlatformNES::notifyInsDeletion(void* ins) {
diff --git a/src/engine/platform/nes.h b/src/engine/platform/nes.h
index 3249da985..52814fee0 100644
--- a/src/engine/platform/nes.h
+++ b/src/engine/platform/nes.h
@@ -41,7 +41,6 @@ class DivPlatformNES: public DivDispatch {
   unsigned char apuType;
   struct NESAPU* nes;
 
-  float freqBase;
   friend void putDispatchChan(void*,int,int);
 
   public:
diff --git a/src/engine/platform/pce.cpp b/src/engine/platform/pce.cpp
index 2b957928d..06a1b2fd2 100644
--- a/src/engine/platform/pce.cpp
+++ b/src/engine/platform/pce.cpp
@@ -13,7 +13,7 @@
     rWrite(a,v); \
   }
 
-#define FREQ_BASE 1712.0f*2
+#define CHIP_DIVIDER 32
 
 void DivPlatformPCE::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   for (size_t h=start; h<start+len; h++) {
@@ -109,18 +109,18 @@ void DivPlatformPCE::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
           // noise
           chWrite(i,0x07,chan[i].noise?(0x80|noiseFreq[(chan[i].std.arp)%12]):0);
         } else {
-          chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
           chWrite(i,0x07,chan[i].noise?(0x80|noiseFreq[(chan[i].note+chan[i].std.arp)%12]):0);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chWrite(i,0x07,chan[i].noise?(0x80|noiseFreq[chan[i].note%12]):0);
         chan[i].freqChanged=true;
       }
@@ -136,7 +136,7 @@ void DivPlatformPCE::tick() {
       //DivInstrument* ins=parent->getIns(chan[i].ins);
       chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,true);
       if (chan[i].furnaceDac) {
-        chan[i].dacRate=1789773/chan[i].freq;
+        chan[i].dacRate=chipClock/chan[i].freq;
         if (dumpWrites) addWrite(0xffff0001+(i<<8),chan[i].dacRate);
       }
       if (chan[i].freq>4095) chan[i].freq=4095;
@@ -186,7 +186,7 @@ int DivPlatformPCE::dispatch(DivCommand c) {
           chan[c.chan].dacPos=0;
           chan[c.chan].dacPeriod=0;
           if (c.value!=DIV_NOTE_NULL) {
-            chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+            chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
             chan[c.chan].freqChanged=true;
             chan[c.chan].note=c.value;
           }
@@ -215,7 +215,7 @@ int DivPlatformPCE::dispatch(DivCommand c) {
         break;
       }
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+        chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
         chWrite(c.chan,0x07,chan[c.chan].noise?(0x80|noiseFreq[chan[c.chan].note%12]):0);
@@ -270,7 +270,7 @@ int DivPlatformPCE::dispatch(DivCommand c) {
       rWrite(0x08,c.value);
       break;
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_PERIODIC(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -311,7 +311,7 @@ int DivPlatformPCE::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_LEGATO:
-      chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)))/12.0f)));
+      chan[c.chan].baseFreq=NOTE_PERIODIC(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)));
       chan[c.chan].freqChanged=true;
       chan[c.chan].note=c.value;
       break;
@@ -398,10 +398,11 @@ void DivPlatformPCE::notifyInsDeletion(void* ins) {
 
 void DivPlatformPCE::setPAL(bool pal) {
   if (pal) { // technically there is no PAL PC Engine but oh well...
-    rate=1773448/6;
+    chipClock=COLOR_PAL*4.0/5.0;
   } else {
-    rate=1789773/6;
+    chipClock=COLOR_NTSC;
   }
+  rate=chipClock/12;
 }
 
 int DivPlatformPCE::init(DivEngine* p, int channels, int sugRate, bool pal) {
diff --git a/src/engine/platform/saa.cpp b/src/engine/platform/saa.cpp
index 6cc341a1e..fb678ac81 100644
--- a/src/engine/platform/saa.cpp
+++ b/src/engine/platform/saa.cpp
@@ -6,7 +6,7 @@
 
 #define rWrite(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
 
-#define PSG_FREQ_BASE 122240.0f
+#define CHIP_DIVIDER 2
 
 void DivPlatformSAA1099::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   if (saaBufLen<len) {
@@ -48,15 +48,15 @@ void DivPlatformSAA1099::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
         } else {
-          chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -124,7 +124,7 @@ int DivPlatformSAA1099::dispatch(DivCommand c) {
     case DIV_CMD_NOTE_ON: {
       DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+        chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
       }
@@ -171,7 +171,7 @@ int DivPlatformSAA1099::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_PERIODIC(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value*(8-chan[c.chan].freqH);
@@ -202,7 +202,7 @@ int DivPlatformSAA1099::dispatch(DivCommand c) {
       }
       break;
     case DIV_CMD_LEGATO: {
-      chan[c.chan].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+      chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
       chan[c.chan].freqChanged=true;
       break;
     }
@@ -308,11 +308,8 @@ void DivPlatformSAA1099::notifyInsDeletion(void* ins) {
 }
 
 void DivPlatformSAA1099::setPAL(bool pal) {
-  if (pal) {
-    rate=250000;
-  } else {
-    rate=250000;
-  }
+  chipClock=8000000;
+  rate=chipClock/32;
 }
 
 int DivPlatformSAA1099::init(DivEngine* p, int channels, int sugRate, bool pal) {
diff --git a/src/engine/platform/sms.cpp b/src/engine/platform/sms.cpp
index 70d3d4bf7..4a0e03d7d 100644
--- a/src/engine/platform/sms.cpp
+++ b/src/engine/platform/sms.cpp
@@ -2,10 +2,10 @@
 #include "../engine.h"
 #include <math.h>
 
-#define FREQ_BASE 1712.0f
-
 #define rWrite(v) {if (!skipRegisterWrites) {sn->write(v); if (dumpWrites) {addWrite(0x200,v);}}}
 
+#define CHIP_DIVIDER 64
+
 void DivPlatformSMS::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   sn->sound_stream_update(bufL+start,len);
 }
@@ -25,14 +25,14 @@ void DivPlatformSMS::tick() {
     }
     if (chan[i].std.hadArp) {
       if (chan[i].std.arpMode) {
-        chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
       } else {
-        chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -93,7 +93,7 @@ int DivPlatformSMS::dispatch(DivCommand c) {
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON:
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+        chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
       }
@@ -130,7 +130,7 @@ int DivPlatformSMS::dispatch(DivCommand c) {
       chan[c.chan].freqChanged=true;
       break;
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=round(FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
+      int destFreq=NOTE_PERIODIC(c.value2);
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
         chan[c.chan].baseFreq+=c.value;
@@ -154,7 +154,7 @@ int DivPlatformSMS::dispatch(DivCommand c) {
       updateSNMode=true;
       break;
     case DIV_CMD_LEGATO:
-      chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)))/12.0f)));
+      chan[c.chan].baseFreq=NOTE_PERIODIC(c.value+((chan[c.chan].std.willArp && !chan[c.chan].std.arpMode)?(chan[c.chan].std.arp):(0)));
       chan[c.chan].freqChanged=true;
       chan[c.chan].note=c.value;
       break;
@@ -223,10 +223,11 @@ void DivPlatformSMS::notifyInsDeletion(void* ins) {
 
 void DivPlatformSMS::setPAL(bool pal) {
   if (pal) {
-    rate=221681;
+    chipClock=COLOR_PAL*4.0/5.0;
   } else {
-    rate=223722;
+    chipClock=COLOR_NTSC;
   }
+  rate=chipClock/16;
 }
 
 int DivPlatformSMS::init(DivEngine* p, int channels, int sugRate, bool pal) {
diff --git a/src/engine/platform/tia.cpp b/src/engine/platform/tia.cpp
index ebd587cc0..fb39940fa 100644
--- a/src/engine/platform/tia.cpp
+++ b/src/engine/platform/tia.cpp
@@ -9,12 +9,12 @@ void DivPlatformTIA::acquire(short* bufL, short* bufR, size_t start, size_t len)
   tia.process(bufL+start,len);
 }
 
-unsigned char dealWithFreq(unsigned char shape, int base, int pitch) {
+unsigned char DivPlatformTIA::dealWithFreq(unsigned char shape, int base, int pitch) {
   if (base&0x80000000 && ((base&0x7fffffff)<32)) {
     return base&0x1f;
   }
   int bp=base+pitch;
-  double mult=0.25*27.5*pow(2.0,double(768+bp)/(256.0*12.0));
+  double mult=0.25*(parent->song.tuning*0.0625)*pow(2.0,double(768+bp)/(256.0*12.0));
   switch (shape) {
     case 1: // buzzy
       return ceil(31400/(30.6*mult))-1;
diff --git a/src/engine/platform/tia.h b/src/engine/platform/tia.h
index 180e20351..2828b00e8 100644
--- a/src/engine/platform/tia.h
+++ b/src/engine/platform/tia.h
@@ -20,6 +20,8 @@ class DivPlatformTIA: public DivDispatch {
     bool isMuted[2];
     TIASound tia;
     friend void putDispatchChan(void*,int,int);
+
+    unsigned char dealWithFreq(unsigned char shape, int base, int pitch);
   
   public:
     void acquire(short* bufL, short* bufR, size_t start, size_t len);
diff --git a/src/engine/platform/ym2610.cpp b/src/engine/platform/ym2610.cpp
index 0ffd4775e..4196a1e44 100644
--- a/src/engine/platform/ym2610.cpp
+++ b/src/engine/platform/ym2610.cpp
@@ -11,6 +11,8 @@ static unsigned char konOffs[4]={
   1, 2, 5, 6
 };
 
+#define CHIP_DIVIDER 32
+
 void DivPlatformYM2610::acquire(short* bufL, short* bufR, size_t start, size_t len) {
   static int os[2];
 
@@ -57,15 +59,15 @@ void DivPlatformYM2610::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].std.arp);
         } else {
-          chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].note+chan[i].std.arp)/12.0f)));
+          chan[i].baseFreq=NOTE_PERIODIC(chan[i].note+chan[i].std.arp);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)(chan[i].note)/12.0f)));
+        chan[i].baseFreq=NOTE_PERIODIC(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -165,15 +167,15 @@ void DivPlatformYM2610::tick() {
     if (chan[i].std.hadArp) {
       if (!chan[i].inPorta) {
         if (chan[i].std.arpMode) {
-          chan[i].baseFreq=FM_FREQ_BASE*pow(2.0f,((float)chan[i].std.arp/12.0f));
+          chan[i].baseFreq=NOTE_FREQUENCY(chan[i].std.arp);
         } else {
-          chan[i].baseFreq=FM_FREQ_BASE*pow(2.0f,((float)(chan[i].note+(signed char)chan[i].std.arp)/12.0f));
+          chan[i].baseFreq=NOTE_FREQUENCY(chan[i].note+(signed char)chan[i].std.arp);
         }
       }
       chan[i].freqChanged=true;
     } else {
       if (chan[i].std.arpMode && chan[i].std.finishedArp) {
-        chan[i].baseFreq=FM_FREQ_BASE*pow(2.0f,((float)chan[i].note/12.0f));
+        chan[i].baseFreq=NOTE_FREQUENCY(chan[i].note);
         chan[i].freqChanged=true;
       }
     }
@@ -278,19 +280,19 @@ void DivPlatformYM2610::tick() {
 }
 
 int DivPlatformYM2610::octave(int freq) {
-  if (freq>=FM_FREQ_BASE*128) {
+  if (freq>=622.0f*128) {
     return 128;
-  } else if (freq>=FM_FREQ_BASE*64) {
+  } else if (freq>=622.0f*64) {
     return 64;
-  } else if (freq>=FM_FREQ_BASE*32) {
+  } else if (freq>=622.0f*32) {
     return 32;
-  } else if (freq>=FM_FREQ_BASE*16) {
+  } else if (freq>=622.0f*16) {
     return 16;
-  } else if (freq>=FM_FREQ_BASE*8) {
+  } else if (freq>=622.0f*8) {
     return 8;
-  } else if (freq>=FM_FREQ_BASE*4) {
+  } else if (freq>=622.0f*4) {
     return 4;
-  } else if (freq>=FM_FREQ_BASE*2) {
+  } else if (freq>=622.0f*2) {
     return 2;
   } else {
     return 1;
@@ -299,19 +301,19 @@ int DivPlatformYM2610::octave(int freq) {
 }
 
 int DivPlatformYM2610::toFreq(int freq) {
-  if (freq>=FM_FREQ_BASE*128) {
+  if (freq>=622.0f*128) {
     return 0x3800|((freq>>7)&0x7ff);
-  } else if (freq>=FM_FREQ_BASE*64) {
+  } else if (freq>=622.0f*64) {
     return 0x3000|((freq>>6)&0x7ff);
-  } else if (freq>=FM_FREQ_BASE*32) {
+  } else if (freq>=622.0f*32) {
     return 0x2800|((freq>>5)&0x7ff);
-  } else if (freq>=FM_FREQ_BASE*16) {
+  } else if (freq>=622.0f*16) {
     return 0x2000|((freq>>4)&0x7ff);
-  } else if (freq>=FM_FREQ_BASE*8) {
+  } else if (freq>=622.0f*8) {
     return 0x1800|((freq>>3)&0x7ff);
-  } else if (freq>=FM_FREQ_BASE*4) {
+  } else if (freq>=622.0f*4) {
     return 0x1000|((freq>>2)&0x7ff);
-  } else if (freq>=FM_FREQ_BASE*2) {
+  } else if (freq>=622.0f*2) {
     return 0x800|((freq>>1)&0x7ff);
   } else {
     return freq&0x7ff;
@@ -351,7 +353,7 @@ int DivPlatformYM2610::dispatch(DivCommand c) {
 
       if (c.chan>3) { // PSG
         if (c.value!=DIV_NOTE_NULL) {
-          chan[c.chan].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+          chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
           chan[c.chan].freqChanged=true;
           chan[c.chan].note=c.value;
         }
@@ -397,7 +399,7 @@ int DivPlatformYM2610::dispatch(DivCommand c) {
       chan[c.chan].insChanged=false;
 
       if (c.value!=DIV_NOTE_NULL) {
-        chan[c.chan].baseFreq=FM_FREQ_BASE*pow(2.0f,((float)c.value/12.0f));
+        chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
         chan[c.chan].freqChanged=true;
         chan[c.chan].note=c.value;
       }
@@ -479,7 +481,7 @@ int DivPlatformYM2610::dispatch(DivCommand c) {
     }
     case DIV_CMD_NOTE_PORTA: {
       if (c.chan>3) { // PSG
-        int destFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
+        int destFreq=NOTE_PERIODIC(c.value2);
         bool return2=false;
         if (destFreq>chan[c.chan].baseFreq) {
           chan[c.chan].baseFreq+=c.value;
@@ -502,7 +504,7 @@ int DivPlatformYM2610::dispatch(DivCommand c) {
         break;
       }
 
-      int destFreq=FM_FREQ_BASE*pow(2.0f,((float)c.value2/12.0f));
+      int destFreq=NOTE_FREQUENCY(c.value2);
       int newFreq;
       bool return2=false;
       if (destFreq>chan[c.chan].baseFreq) {
@@ -539,9 +541,9 @@ int DivPlatformYM2610::dispatch(DivCommand c) {
       break;
     case DIV_CMD_LEGATO: {
       if (c.chan>3) { // PSG
-        chan[c.chan].baseFreq=round(PSG_FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+        chan[c.chan].baseFreq=NOTE_PERIODIC(c.value);
       } else {
-        chan[c.chan].baseFreq=FM_FREQ_BASE*pow(2.0f,((float)c.value/12.0f));
+        chan[c.chan].baseFreq=NOTE_FREQUENCY(c.value);
       }
       chan[c.chan].freqChanged=true;
       break;
@@ -794,11 +796,8 @@ int DivPlatformYM2610::init(DivEngine* p, int channels, int sugRate, bool pal) {
   for (int i=0; i<13; i++) {
     isMuted[i]=false;
   }
-  if (pal) {
-    rate=500000;
-  } else {
-    rate=500000;
-  }
+  chipClock=8000000;
+  rate=chipClock/16;
   iface.parent=parent;
   iface.sampleBank=0;
   fm=new ymfm::ym2610(iface);
diff --git a/src/engine/platform/ym2610ext.cpp b/src/engine/platform/ym2610ext.cpp
index 71072edad..055dfeda3 100644
--- a/src/engine/platform/ym2610ext.cpp
+++ b/src/engine/platform/ym2610ext.cpp
@@ -46,7 +46,7 @@ int DivPlatformYM2610Ext::dispatch(DivCommand c) {
       opChan[ch].insChanged=false;
 
       if (c.value!=DIV_NOTE_NULL) {
-        opChan[ch].baseFreq=FM_FREQ_BASE*pow(2.0f,((float)c.value/12.0f));
+        opChan[ch].baseFreq=NOTE_FREQUENCY(c.value);
         opChan[ch].freqChanged=true;
       }
       opChan[ch].keyOn=true;
@@ -102,7 +102,7 @@ int DivPlatformYM2610Ext::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_NOTE_PORTA: {
-      int destFreq=FM_FREQ_BASE*pow(2.0f,((float)c.value2/12.0f));
+      int destFreq=NOTE_FREQUENCY(c.value2);
       int newFreq;
       bool return2=false;
       if (destFreq>opChan[ch].baseFreq) {
@@ -135,7 +135,7 @@ int DivPlatformYM2610Ext::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_LEGATO: {
-      opChan[ch].baseFreq=FM_FREQ_BASE*pow(2.0f,((float)c.value/12.0f));
+      opChan[ch].baseFreq=NOTE_FREQUENCY(c.value);
       opChan[ch].freqChanged=true;
       break;
     }
diff --git a/src/engine/platform/ym2610shared.h b/src/engine/platform/ym2610shared.h
index 169db0d79..d7c792d07 100644
--- a/src/engine/platform/ym2610shared.h
+++ b/src/engine/platform/ym2610shared.h
@@ -26,5 +26,4 @@ static int orderedOps[4]={
 #define rWrite(a,v) if (!skipRegisterWrites) {pendingWrites[a]=v;}
 #define immWrite(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
 
-#define FM_FREQ_BASE 622.0f
-#define PSG_FREQ_BASE 7640.0f
+#define CHIP_FREQBASE 9509775
\ No newline at end of file
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 22aed29b4..a8a2052fa 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1005,6 +1005,11 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
   }
 
   if (!playing) {
+    if (out!=NULL) {
+      memcpy(oscBuf[0],out[0],size*sizeof(float));
+      memcpy(oscBuf[1],out[1],size*sizeof(float));
+      oscSize=size;
+    }
     isBusy.unlock();
     return;
   }
@@ -1139,7 +1144,6 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
     while (metroPos>=1) metroPos--;
   }
 
-  // TODO: improve
   memcpy(oscBuf[0],out[0],size*sizeof(float));
   memcpy(oscBuf[1],out[1],size*sizeof(float));
   oscSize=size;
diff --git a/src/engine/song.h b/src/engine/song.h
index d05975a83..e19469467 100644
--- a/src/engine/song.h
+++ b/src/engine/song.h
@@ -106,6 +106,7 @@ struct DivSong {
   bool pal;
   bool customTempo;
   int hz, patLen, ordersLen, insLen, waveLen, sampleLen;
+  float tuning;
 
   // compatibility flags
   bool limitSlides; // limit slide range
@@ -151,6 +152,7 @@ struct DivSong {
     insLen(0),
     waveLen(0),
     sampleLen(0),
+    tuning(440.0f),
     limitSlides(false) {
     for (int i=0; i<32; i++) {
       system[i]=DIV_SYSTEM_NULL;
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index f76e270e5..04342ec2c 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -569,6 +569,16 @@ void FurnaceGUI::drawSongInfo() {
       ImGui::SameLine();
       ImGui::Text("NTSC");
     }
+
+    ImGui::Text("Tuning (A-4)");
+    ImGui::SameLine();
+    float tune=e->song.tuning;
+    ImGui::SetNextItemWidth(120.0f*dpiScale);
+    if (ImGui::InputFloat("##Tuning",&tune,1.0f,3.0f,"%g")) {
+      if (tune<220.0f) tune=220.0f;
+      if (tune>660.0f) tune=660.0f;
+      e->song.tuning=tune;
+    }
   }
   if (ImGui::IsWindowFocused()) curWindow=GUI_WINDOW_SONG_INFO;
   ImGui::End();
@@ -1980,19 +1990,20 @@ void FurnaceGUI::drawMixer() {
 void FurnaceGUI::drawOsc() {
   if (!oscOpen) return;
   ImGui::SetNextWindowSizeConstraints(ImVec2(64.0f*dpiScale,32.0f*dpiScale),ImVec2(scrW*dpiScale,scrH*dpiScale));
+  ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding,ImVec2(0,0));
+  ImGui::PushStyleVar(ImGuiStyleVar_FramePadding,ImVec2(0,0));
+  ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing,ImVec2(0,0));
+  ImGui::PushStyleVar(ImGuiStyleVar_ItemInnerSpacing,ImVec2(0,0));
   if (ImGui::Begin("Oscilloscope",&oscOpen)) {
-    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding,ImVec2(0,0));
-    ImGui::PushStyleVar(ImGuiStyleVar_FramePadding,ImVec2(0,0));
-    ImGui::PushStyleVar(ImGuiStyleVar_ItemSpacing,ImVec2(0,0));
-    ImGui::PushStyleVar(ImGuiStyleVar_ItemInnerSpacing,ImVec2(0,0));
     float values[512];
     for (int i=0; i<512; i++) {
       int pos=i*e->oscSize/512;
       values[i]=(e->oscBuf[0][pos]+e->oscBuf[1][pos])*0.5f;
     }
+    //ImGui::SetCursorPos(ImVec2(0,0));
     ImGui::PlotLines("##SingleOsc",values,512,0,NULL,-1.0f,1.0f,ImGui::GetContentRegionAvail());
-    ImGui::PopStyleVar(4);
   }
+  ImGui::PopStyleVar(4);
   ImGui::End();
 }