prepare for proper center rate

the correct rate is 8372Hz rather than 8363Hz
sadly this will require a compat flag so I am not making this change
effective until 0.7

issue #2347

src/engine/engine.cpp

@@ -2353,6 +2353,10 @@ double DivEngine::getSamplePreviewRate() {
   return sPreview.rate;
 }
 
+double DivEngine::getCenterRate() {
+  return song.oldCenterRate?8363.0:8372.0;
+}
+
 String DivEngine::getConfigPath() {
   return configPath;
 }
@@ -2897,6 +2901,7 @@ int DivEngine::addSample() {
   DivSample* sample=new DivSample;
   int sampleCount=(int)song.sample.size();
   sample->name=fmt::sprintf(_("Sample %d"),sampleCount);
+  sample->centerRate=getCenterRate();
   song.sample.push_back(sample);
   song.sampleLen=sampleCount+1;
   sPreview.sample=-1;

src/engine/engine.h

@@ -839,6 +839,9 @@ class DivEngine {
     // reset playback state
     void syncReset();
 
+    // get C-4 rate for samples
+    double getCenterRate();
+
     // sample preview query
     bool isPreviewingSample();
     int getSamplePreviewSample();

src/engine/platform/amiga.cpp

@@ -429,7 +429,7 @@ void DivPlatformAmiga::tick(bool sysTick) {
       if (s->centerRate<1) {
         off=1.0;
       } else {
-        off=8363.0/(double)s->centerRate;
+        off=parent->getCenterRate()/(double)s->centerRate;
       }
     }
     if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {

src/engine/platform/ay.cpp

@@ -515,7 +515,7 @@ void DivPlatformAY8910::tick(bool sysTick) {
           if (s->centerRate<1) {
             off=1.0;
           } else {
-            off=8363.0/(double)s->centerRate;
+            off=parent->getCenterRate()/(double)s->centerRate;
           }
         }
         chan[i].dac.rate=((double)rate*((sunsoft||clockSel)?8.0:16.0))/(double)(MAX(1,off*chan[i].freq));

src/engine/platform/ay8930.cpp

@@ -341,7 +341,7 @@ void DivPlatformAY8930::tick(bool sysTick) {
           if (s->centerRate<1) {
             off=1.0;
           } else {
-            off=8363.0/(double)s->centerRate;
+            off=parent->getCenterRate()/(double)s->centerRate;
           }
         }
         chan[i].dac.rate=((double)chipClock*4.0)/(double)(MAX(1,off*chan[i].freq));

src/engine/platform/c140.cpp

@@ -214,7 +214,7 @@ void DivPlatformC140::tick(bool sysTick) {
     if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
       DivSample* s=parent->getSample(chan[i].sample);
       unsigned char ctrl=0;
-      double off=(s->centerRate>=1)?((double)s->centerRate/8363.0):1.0;
+      double off=(s->centerRate>=1)?((double)s->centerRate/parent->getCenterRate()):1.0;
       chan[i].freq=(int)(off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,chipClock,CHIP_FREQBASE));
       if (chan[i].freq<0) chan[i].freq=0;
       if (chan[i].freq>65535) chan[i].freq=65535;

src/engine/platform/c64.cpp

@@ -373,7 +373,7 @@ void DivPlatformC64::tick(bool sysTick) {
       if (s->centerRate<1) {
         off=1.0;
       } else {
-        off=(double)s->centerRate/8363.0;
+        off=(double)s->centerRate/parent->getCenterRate();
       }
     }
     chan[i].pcmRate=off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,2,1);

src/engine/platform/dave.cpp

@@ -239,7 +239,7 @@ void DivPlatformDave::tick(bool sysTick) {
         double off=1.0;
         if (chan[i].dacSample>=0 && chan[i].dacSample<parent->song.sampleLen) {
           DivSample* s=parent->getSample(chan[i].dacSample);
-          off=(double)s->centerRate/8363.0;
+          off=(double)s->centerRate/parent->getCenterRate();
         }
         chan[i].dacRate=chan[i].freq*off;
       } else {

src/engine/platform/es5506.cpp

@@ -490,7 +490,7 @@ void DivPlatformES5506::tick(bool sysTick) {
             if (center<1) {
               off=1.0;
             } else {
-              off=(double)center/8363.0;
+              off=(double)center/parent->getCenterRate();
             }
             if (ins->amiga.useNoteMap) {
               //chan[i].pcm.note=next;
@@ -654,7 +654,7 @@ void DivPlatformES5506::tick(bool sysTick) {
           if (center<1) {
             off=1.0;
           } else {
-            off=(double)center/8363.0;
+            off=(double)center/parent->getCenterRate();
           }
           chan[i].pcm.loopStart=(chan[i].pcm.start+(s->loopStart<<11))&0xfffff800;
           chan[i].pcm.loopEnd=(chan[i].pcm.start+((s->loopEnd)<<11))&0xffffff80;

src/engine/platform/ga20.cpp

@@ -145,7 +145,7 @@ void DivPlatformGA20::tick(bool sysTick) {
         if (s->centerRate<1) {
           off=1.0;
         } else {
-          off=8363.0/s->centerRate;
+          off=parent->getCenterRate()/s->centerRate;
         }
       }
       DivSample* s=parent->getSample(chan[i].sample);

src/engine/platform/gbadma.cpp

@@ -159,7 +159,7 @@ void DivPlatformGBADMA::tick(bool sysTick) {
       double off=1.0;
       if (!chan[i].useWave && chan[i].sample>=0 && chan[i].sample<parent->song.sampleLen) {
         DivSample* s=parent->getSample(chan[i].sample);
-        off=(s->centerRate>=1)?(8363.0/(double)s->centerRate):1.0;
+        off=(s->centerRate>=1)?(parent->getCenterRate()/(double)s->centerRate):1.0;
       }
       chan[i].freq=off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,true,0,chan[i].pitch2,chipClock,CHIP_DIVIDER);
 

src/engine/platform/gbaminmod.cpp

@@ -295,7 +295,7 @@ void DivPlatformGBAMinMod::tick(bool sysTick) {
     }
     if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
       DivSample* s=parent->getSample(chan[i].sample);
-      double off=(s->centerRate>=1)?((double)s->centerRate/8363.0):1.0;
+      double off=(s->centerRate>=1)?((double)s->centerRate/parent->getCenterRate()):1.0;
       chan[i].freq=(int)(off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,chipClock,CHIP_FREQBASE));
       if (chan[i].keyOn) {
         unsigned int start, end, loop;

src/engine/platform/genesis.cpp

@@ -865,7 +865,7 @@ void DivPlatformGenesis::tick(bool sysTick) {
           if (s->centerRate<1) {
             off=1.0;
           } else {
-            off=(double)s->centerRate/8363.0;
+            off=(double)s->centerRate/parent->getCenterRate();
           }
         }
         chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,1,1);

src/engine/platform/k007232.cpp

@@ -187,7 +187,7 @@ void DivPlatformK007232::tick(bool sysTick) {
         if (s->centerRate<1) {
           off=1.0;
         } else {
-          off=8363.0/s->centerRate;
+          off=parent->getCenterRate()/s->centerRate;
         }
       }
       DivSample* s=parent->getSample(chan[i].sample);

src/engine/platform/k053260.cpp

@@ -142,7 +142,7 @@ void DivPlatformK053260::tick(bool sysTick) {
         if (s->centerRate<1) {
           off=1.0;
         } else {
-          off=8363.0/s->centerRate;
+          off=parent->getCenterRate()/s->centerRate;
         }
       }
       chan[i].freq=0x1000-(int)(off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,true,0,chan[i].pitch2,chipClock,CHIP_DIVIDER));

src/engine/platform/lynx.cpp

@@ -257,7 +257,7 @@ void DivPlatformLynx::tick(bool sysTick) {
           if (s->centerRate<1) {
             off=1.0;
           } else {
-            off=(double)s->centerRate/8363.0;
+            off=(double)s->centerRate/parent->getCenterRate();
           }
         }
         chan[i].sampleFreq=off*parent->calcFreq(chan[i].sampleBaseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,chipClock,CHIP_FREQBASE);

src/engine/platform/mmc5.cpp

@@ -161,7 +161,7 @@ void DivPlatformMMC5::tick(bool sysTick) {
       double off=1.0;
       if (dacSample>=0 && dacSample<parent->song.sampleLen) {
         DivSample* s=parent->getSample(dacSample);
-        off=(double)s->centerRate/8363.0;
+        off=(double)s->centerRate/parent->getCenterRate();
       }
       dacRate=MIN(chan[2].freq*off,32000);
       if (dumpWrites) addWrite(0xffff0001,dacRate);

src/engine/platform/nds.cpp

@@ -160,7 +160,7 @@ void DivPlatformNDS::tick(bool sysTick) {
           case DIV_SAMPLE_DEPTH_16BIT: ctrl=0x20; break;
           default: break;
         }
-        double off=(s->centerRate>=1)?(8363.0/(double)s->centerRate):1.0;
+        double off=(s->centerRate>=1)?(parent->getCenterRate()/(double)s->centerRate):1.0;
         chan[i].freq=0x10000-(off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,true,0,chan[i].pitch2,chipClock,CHIP_DIVIDER));
         if (chan[i].freq<0) chan[i].freq=0;
         if (chan[i].freq>65535) chan[i].freq=65535;

src/engine/platform/nes.cpp

@@ -391,7 +391,7 @@ void DivPlatformNES::tick(bool sysTick) {
       double off=1.0;
       if (dacSample>=0 && dacSample<parent->song.sampleLen) {
         DivSample* s=parent->getSample(dacSample);
-        off=(double)s->centerRate/8363.0;
+        off=(double)s->centerRate/parent->getCenterRate();
       }
       dacRate=MIN(chan[4].freq*off,32000);
       if (chan[4].keyOn) {

src/engine/platform/opl.cpp

@@ -1004,7 +1004,7 @@ void DivPlatformOPL::acquire(short** buf, size_t len) {
 double DivPlatformOPL::NOTE_ADPCMB(int note) {
   if (adpcmChan<0) return 0;
   if (chan[adpcmChan].sample>=0 && chan[adpcmChan].sample<parent->song.sampleLen) {
-    double off=65535.0*(double)(parent->getSample(chan[adpcmChan].sample)->centerRate)/8363.0;
+    double off=65535.0*(double)(parent->getSample(chan[adpcmChan].sample)->centerRate)/parent->getCenterRate();
     return parent->calcBaseFreq((double)chipClock/(compatYPitch?144:72),off,note,false);
   }
   return 0;
@@ -1334,7 +1334,7 @@ void DivPlatformOPL::tick(bool sysTick) {
     }
     if (chan[adpcmChan].freqChanged || chan[adpcmChan].keyOn || chan[adpcmChan].keyOff) {
       if (chan[adpcmChan].sample>=0 && chan[adpcmChan].sample<parent->song.sampleLen) {
-        double off=65535.0*(double)(parent->getSample(chan[adpcmChan].sample)->centerRate)/8363.0;
+        double off=65535.0*(double)(parent->getSample(chan[adpcmChan].sample)->centerRate)/parent->getCenterRate();
         chan[adpcmChan].freq=parent->calcFreq(chan[adpcmChan].baseFreq,chan[adpcmChan].pitch,chan[adpcmChan].fixedArp?chan[adpcmChan].baseNoteOverride:chan[adpcmChan].arpOff,chan[adpcmChan].fixedArp,false,4,chan[adpcmChan].pitch2,(double)chipClock/(compatYPitch?144:72),off);
       } else {
         chan[adpcmChan].freq=0;
@@ -1384,7 +1384,7 @@ void DivPlatformOPL::tick(bool sysTick) {
       if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
         DivSample* s=parent->getSample(chan[i].sample);
         unsigned char ctrl=0;
-        double off=(s->centerRate>=1)?((double)s->centerRate/8363.0):1.0;
+        double off=(s->centerRate>=1)?((double)s->centerRate/parent->getCenterRate()):1.0;
         chan[i].freq=(int)(off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,chipClock,(524288*768)));
         if (chan[i].freq<0x400) chan[i].freq=0x400;
         chan[i].freqH=0;

src/engine/platform/pce.cpp

@@ -233,7 +233,7 @@ void DivPlatformPCE::tick(bool sysTick) {
           if (s->centerRate<1) {
             off=1.0;
           } else {
-            off=8363.0/(double)s->centerRate;
+            off=parent->getCenterRate()/(double)s->centerRate;
           }
         }
         chan[i].dacRate=((double)chipClock/2)/MAX(1,off*chan[i].freq);

src/engine/platform/pcmdac.cpp

@@ -292,7 +292,7 @@ void DivPlatformPCMDAC::tick(bool sysTick) {
     double off=1.0;
     if (!chan[0].useWave && chan[0].sample>=0 && chan[0].sample<parent->song.sampleLen) {
       DivSample* s=parent->getSample(chan[0].sample);
-      off=(s->centerRate>=1)?((double)s->centerRate/8363.0):1.0;
+      off=(s->centerRate>=1)?((double)s->centerRate/parent->getCenterRate()):1.0;
     }
     chan[0].freq=off*parent->calcFreq(chan[0].baseFreq,chan[0].pitch,chan[0].fixedArp?chan[0].baseNoteOverride:chan[0].arpOff,chan[0].fixedArp,false,2,chan[0].pitch2,chipClock,CHIP_FREQBASE);
     if (chan[0].freq>16777215) chan[0].freq=16777215;

src/engine/platform/rf5c68.cpp

@@ -135,7 +135,7 @@ void DivPlatformRF5C68::tick(bool sysTick) {
       unsigned char keyon=regPool[8]&~(1<<i);
       unsigned char keyoff=keyon|(1<<i);
       DivSample* s=parent->getSample(chan[i].sample);
-      double off=(s->centerRate>=1)?((double)s->centerRate/8363.0):1.0;
+      double off=(s->centerRate>=1)?((double)s->centerRate/parent->getCenterRate()):1.0;
       chan[i].freq=(int)(off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,chipClock,CHIP_FREQBASE));
       if (chan[i].freq>65535) chan[i].freq=65535;
       if (chan[i].keyOn) {

src/engine/platform/segapcm.cpp

@@ -119,7 +119,7 @@ void DivPlatformSegaPCM::tick(bool sysTick) {
         double off=1.0;
         if (chan[i].pcm.sample>=0 && chan[i].pcm.sample<parent->song.sampleLen) {
           DivSample* s=parent->getSample(chan[i].pcm.sample);
-          off=(double)s->centerRate/8363.0;
+          off=(double)s->centerRate/parent->getCenterRate();
         }
         chan[i].pcm.freq=MIN(255,((rate*0.5)+(off*parent->song.tuning*pow(2.0,double(chan[i].freq+512)/(128.0*12.0)))*255)/rate)+(oldSlides?chan[i].pitch2:0);
         rWrite(7+(i<<3),chan[i].pcm.freq);

src/engine/platform/sid3.cpp

@@ -716,7 +716,7 @@ void DivPlatformSID3::tick(bool sysTick)
           if (s->centerRate<1) {
             off=1.0;
           } else {
-            off=(double)s->centerRate/8363.0;
+            off=(double)s->centerRate/parent->getCenterRate();
           }
         }
         chan[i].dacRate=chan[i].freq*(off / 32.0)*(double)chipClock/1000000.0;

src/engine/platform/snes.cpp

@@ -208,7 +208,7 @@ void DivPlatformSNES::tick(bool sysTick) {
     // TODO: if wavetable length is higher than 32, we lose precision!
     if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
       DivSample* s=parent->getSample(chan[i].sample);
-      double off=(s->centerRate>=1)?((double)s->centerRate/8363.0):1.0;
+      double off=(s->centerRate>=1)?((double)s->centerRate/parent->getCenterRate()):1.0;
       if (chan[i].useWave) off=(double)chan[i].wtLen/32.0;
       chan[i].freq=(unsigned int)(off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,chipClock,CHIP_FREQBASE));
       if (chan[i].freq>16383) chan[i].freq=16383;

src/engine/platform/su.cpp

@@ -234,7 +234,7 @@ void DivPlatformSoundUnit::tick(bool sysTick) {
           if (sample->centerRate<1) {
             off=0.25;
           } else {
-            off=(double)sample->centerRate/(8363.0*4.0);
+            off=(double)sample->centerRate/(parent->getCenterRate()*4.0);
           }
           chan[i].freq=(double)chan[i].freq*off;
         }

src/engine/platform/swan.cpp

@@ -185,7 +185,7 @@ void DivPlatformSwan::tick(bool sysTick) {
           if (s->centerRate<1) {
             off=1.0;
           } else {
-            off=8363.0/(double)s->centerRate;
+            off=parent->getCenterRate()/(double)s->centerRate;
           }
         }
         dacRate=((double)chipClock/2)/MAX(1,off*chan[i].freq);

src/engine/platform/vera.cpp

@@ -158,7 +158,7 @@ int DivPlatformVERA::calcNoteFreq(int ch, int note) {
       if (s->centerRate<1) {
         off=65536.0;
       } else {
-        off=65536.0*(s->centerRate/8363.0);
+        off=65536.0*(s->centerRate/parent->getCenterRate());
       }
     }
     return (int)(parent->calcBaseFreq(chipClock,off,note,false));
@@ -230,10 +230,10 @@ void DivPlatformVERA::tick(bool sysTick) {
       DivSample* s=parent->getSample(chan[16].pcm.sample);
       lastCenterRate=s->centerRate;
       if (s->centerRate>=1) {
-        off=65536.0*(s->centerRate/8363.0);
+        off=65536.0*(s->centerRate/parent->getCenterRate());
       }
     } else if (lastCenterRate>=1) {
-      off=65536.0*(lastCenterRate/8363.0);
+      off=65536.0*(lastCenterRate/parent->getCenterRate());
     }
     chan[16].freq=parent->calcFreq(chan[16].baseFreq,chan[16].pitch,chan[16].fixedArp?chan[16].baseNoteOverride:chan[16].arpOff,chan[16].fixedArp,false,8,chan[16].pitch2,chipClock,off);
     if (chan[16].freq>128) chan[16].freq=128;

src/engine/platform/vrc6.cpp

@@ -208,7 +208,7 @@ void DivPlatformVRC6::tick(bool sysTick) {
             if (s->centerRate<1) {
               off=1.0;
             } else {
-              off=8363.0/(double)s->centerRate;
+              off=parent->getCenterRate()/(double)s->centerRate;
             }
           }
           chan[i].dacRate=((double)chipClock)/MAX(1,off*chan[i].freq);

src/engine/platform/x1_010.cpp

@@ -249,7 +249,7 @@ double DivPlatformX1_010::NoteX1_010(int ch, int note) {
       if (s->centerRate<1) {
         off=8192.0;
       } else {
-        off=8192.0*(s->centerRate/8363.0);
+        off=8192.0*(s->centerRate/parent->getCenterRate());
       }
     }
     return parent->calcBaseFreq(chipClock,off,note,false);
@@ -474,7 +474,7 @@ void DivPlatformX1_010::tick(bool sysTick) {
           if (s->centerRate<1) {
             off=8192.0;
           } else {
-            off=8192.0*(s->centerRate/8363.0);
+            off=8192.0*(s->centerRate/parent->getCenterRate());
           }
         }
       }

src/engine/platform/ym2608.cpp

@@ -289,7 +289,7 @@ double DivPlatformYM2608::NOTE_OPNB(int ch, int note) {
 
 double DivPlatformYM2608::NOTE_ADPCMB(int note) {
   if (chan[15+isCSM].sample>=0 && chan[15+isCSM].sample<parent->song.sampleLen) {
-    double off=65535.0*(double)(parent->getSample(chan[15+isCSM].sample)->centerRate)/8363.0;
+    double off=65535.0*(double)(parent->getSample(chan[15+isCSM].sample)->centerRate)/parent->getCenterRate();
     return parent->calcBaseFreq((double)chipClock/144,off,note,false);
   }
   return 0;
@@ -982,7 +982,7 @@ void DivPlatformYM2608::tick(bool sysTick) {
   if (chan[(15+isCSM)].freqChanged || chan[(15+isCSM)].keyOn || chan[(15+isCSM)].keyOff) {
     if (chan[(15+isCSM)].furnacePCM) {
       if (chan[(15+isCSM)].sample>=0 && chan[(15+isCSM)].sample<parent->song.sampleLen) {
-        double off=65535.0*(double)(parent->getSample(chan[(15+isCSM)].sample)->centerRate)/8363.0;
+        double off=65535.0*(double)(parent->getSample(chan[(15+isCSM)].sample)->centerRate)/parent->getCenterRate();
         chan[(15+isCSM)].freq=parent->calcFreq(chan[(15+isCSM)].baseFreq,chan[(15+isCSM)].pitch,chan[(15+isCSM)].fixedArp?chan[(15+isCSM)].baseNoteOverride:chan[(15+isCSM)].arpOff,chan[(15+isCSM)].fixedArp,false,4,chan[(15+isCSM)].pitch2,(double)chipClock/144,off);
       } else {
         chan[(15+isCSM)].freq=0;

src/engine/platform/ym2610.cpp

@@ -912,7 +912,7 @@ void DivPlatformYM2610::tick(bool sysTick) {
   if (chan[adpcmBChanOffs].freqChanged || chan[adpcmBChanOffs].keyOn || chan[adpcmBChanOffs].keyOff) {
     if (chan[adpcmBChanOffs].furnacePCM) {
       if (chan[adpcmBChanOffs].sample>=0 && chan[adpcmBChanOffs].sample<parent->song.sampleLen) {
-        double off=65535.0*(double)(parent->getSample(chan[adpcmBChanOffs].sample)->centerRate)/8363.0;
+        double off=65535.0*(double)(parent->getSample(chan[adpcmBChanOffs].sample)->centerRate)/parent->getCenterRate();
         chan[adpcmBChanOffs].freq=parent->calcFreq(chan[adpcmBChanOffs].baseFreq,chan[adpcmBChanOffs].pitch,chan[adpcmBChanOffs].fixedArp?chan[adpcmBChanOffs].baseNoteOverride:chan[adpcmBChanOffs].arpOff,chan[adpcmBChanOffs].fixedArp,false,4,chan[adpcmBChanOffs].pitch2,(double)chipClock/144,off);
       } else {
         chan[adpcmBChanOffs].freq=0;

src/engine/platform/ym2610b.cpp

@@ -980,7 +980,7 @@ void DivPlatformYM2610B::tick(bool sysTick) {
   if (chan[adpcmBChanOffs].freqChanged || chan[adpcmBChanOffs].keyOn || chan[adpcmBChanOffs].keyOff) {
     if (chan[adpcmBChanOffs].furnacePCM) {
       if (chan[adpcmBChanOffs].sample>=0 && chan[adpcmBChanOffs].sample<parent->song.sampleLen) {
-        double off=65535.0*(double)(parent->getSample(chan[adpcmBChanOffs].sample)->centerRate)/8363.0;
+        double off=65535.0*(double)(parent->getSample(chan[adpcmBChanOffs].sample)->centerRate)/parent->getCenterRate();
         chan[adpcmBChanOffs].freq=parent->calcFreq(chan[adpcmBChanOffs].baseFreq,chan[adpcmBChanOffs].pitch,chan[adpcmBChanOffs].fixedArp?chan[adpcmBChanOffs].baseNoteOverride:chan[adpcmBChanOffs].arpOff,chan[adpcmBChanOffs].fixedArp,false,4,chan[adpcmBChanOffs].pitch2,(double)chipClock/144,off);
       } else {
         chan[adpcmBChanOffs].freq=0;

src/engine/platform/ym2610shared.h

@@ -101,7 +101,7 @@ class DivPlatformYM2610Base: public DivPlatformOPN {
     }
     double NOTE_ADPCMB(int note) {
       if (chan[adpcmBChanOffs].sample>=0 && chan[adpcmBChanOffs].sample<parent->song.sampleLen) {
-        double off=65535.0*(double)(parent->getSample(chan[adpcmBChanOffs].sample)->centerRate)/8363.0;
+        double off=65535.0*(double)(parent->getSample(chan[adpcmBChanOffs].sample)->centerRate)/parent->getCenterRate();
         return parent->calcBaseFreq((double)chipClock/144,off,note,false);
       }
       return 0;

src/engine/platform/ymz280b.cpp

@@ -139,7 +139,7 @@ void DivPlatformYMZ280B::tick(bool sysTick) {
         case DIV_SAMPLE_DEPTH_16BIT: ctrl=0x60; break;
         default: ctrl=0;
       }
-      double off=(s->centerRate>=1)?((double)s->centerRate/8363.0):1.0;
+      double off=(s->centerRate>=1)?((double)s->centerRate/parent->getCenterRate()):1.0;
       chan[i].freq=(int)round(off*parent->calcFreq(chan[i].baseFreq,chan[i].pitch,chan[i].fixedArp?chan[i].baseNoteOverride:chan[i].arpOff,chan[i].fixedArp,false,2,chan[i].pitch2,chipClock,CHIP_FREQBASE)/256.0)-1;
       if (chan[i].freq<0) chan[i].freq=0;
       if (chan[i].freq>511) chan[i].freq=511;

src/engine/platform/zxbeeperquadtone.cpp

@@ -154,7 +154,7 @@ void DivPlatformZXBeeperQuadTone::tick(bool sysTick) {
       double off=CHIP_DIVIDER;
       if (curSample>=0 && curSample<parent->song.sampleLen) {
         DivSample* s=parent->getSample(curSample);
-        off=(s->centerRate>=1)?(CHIP_DIVIDER*(double)s->centerRate/8363.0):CHIP_DIVIDER;
+        off=(s->centerRate>=1)?(CHIP_DIVIDER*(double)s->centerRate/parent->getCenterRate()):CHIP_DIVIDER;
       }
       chan[4].freq=parent->calcFreq(chan[4].baseFreq,chan[4].pitch,chan[4].fixedArp?chan[4].baseNoteOverride:chan[4].arpOff,chan[4].fixedArp,true,2,chan[4].pitch2,chipClock,off);
       if (chan[4].freq>258) chan[4].freq=258;

src/engine/song.h

@@ -352,6 +352,8 @@ struct DivSong {
   bool ceilVolumeScaling;
   bool oldAlwaysSetVolume;
   bool oldSampleOffset;
+  // TODO: this flag is not saved to the file yet.
+  bool oldCenterRate;
 
   std::vector<DivInstrument*> ins;
   std::vector<DivWavetable*> wave;
@@ -481,7 +483,8 @@ struct DivSong {
     resetArpPhaseOnNewNote(false),
     ceilVolumeScaling(false),
     oldAlwaysSetVolume(false),
-    oldSampleOffset(false) {
+    oldSampleOffset(false),
+    oldCenterRate(true) {
     for (int i=0; i<DIV_MAX_CHIPS; i++) {
       system[i]=DIV_SYSTEM_NULL;
       systemVol[i]=1.0;

src/gui/sampleEdit.cpp

@@ -598,7 +598,7 @@ void FurnaceGUI::drawSampleEdit() {
             }
           }
 
-          int sampleNote=round(64.0+(128.0*12.0*log((double)targetRate/8363.0)/log(2.0)));
+          int sampleNote=round(64.0+(128.0*12.0*log((double)targetRate/e->getCenterRate())/log(2.0)));
           int sampleNoteCoarse=60+(sampleNote>>7);
           int sampleNoteFine=(sampleNote&127)-64;
 
@@ -662,7 +662,7 @@ void FurnaceGUI::drawSampleEdit() {
           if (coarseChanged) { MARK_MODIFIED
             sampleNote=((sampleNoteCoarse-60)<<7)+sampleNoteFine;
 
-            targetRate=8363.0*pow(2.0,(double)sampleNote/(128.0*12.0));
+            targetRate=e->getCenterRate()*pow(2.0,(double)sampleNote/(128.0*12.0));
             if (targetRate<100) targetRate=100;
             if (targetRate>384000) targetRate=384000;
 
@@ -685,7 +685,7 @@ void FurnaceGUI::drawSampleEdit() {
 
             sampleNote=((sampleNoteCoarse-60)<<7)+sampleNoteFine;
 
-            targetRate=round(8363.0*pow(2.0,(double)sampleNote/(128.0*12.0)));
+            targetRate=round(e->getCenterRate()*pow(2.0,(double)sampleNote/(128.0*12.0)));
 
             if (targetRate==prevSampleRate) {
               if (prevFine==sampleNoteFine) {