diff --git a/src/engine/platform/ym2203.h b/src/engine/platform/ym2203.h
index 41315659d..ca7dcacda 100644
--- a/src/engine/platform/ym2203.h
+++ b/src/engine/platform/ym2203.h
@@ -94,7 +94,7 @@ class DivPlatformYM2203: public DivPlatformOPN {
     int init(DivEngine* parent, int channels, int sugRate, const DivConfig& flags);
     void quit();
     DivPlatformYM2203():
-      DivPlatformOPN(2, 3, 6, 6, 6, 4720270.0, 36, 16),
+      DivPlatformOPN(2, 3, 6, 6, 6, 4720270.0, 36, 16, false, 6),
       prescale(0x2d),
       isCSM(0) {}
     ~DivPlatformYM2203();
diff --git a/src/engine/platform/ym2203ext.cpp b/src/engine/platform/ym2203ext.cpp
index a3932d527..9e4da8d24 100644
--- a/src/engine/platform/ym2203ext.cpp
+++ b/src/engine/platform/ym2203ext.cpp
@@ -787,6 +787,8 @@ void DivPlatformYM2203Ext::setCSM(bool isCSM) {
   this->isCSM=isCSM?1:0;
   if (isCSM) {
     csmChan=3;
+  } else {
+    csmChan=6;
   }
 }
 
diff --git a/src/engine/platform/ym2608.h b/src/engine/platform/ym2608.h
index d226821a7..a8861b557 100644
--- a/src/engine/platform/ym2608.h
+++ b/src/engine/platform/ym2608.h
@@ -125,7 +125,7 @@ class DivPlatformYM2608: public DivPlatformOPN {
     void setCSM(bool isCSM);
     void quit();
     DivPlatformYM2608():
-      DivPlatformOPN(2, 6, 9, 15, 16, 9440540.0, 72, 32),
+      DivPlatformOPN(2, 6, 9, 15, 16, 9440540.0, 72, 32, false, 16),
       prescale(0x2d),
       isCSM(0) {}
     ~DivPlatformYM2608();
diff --git a/src/engine/platform/ym2610shared.h b/src/engine/platform/ym2610shared.h
index bcec11829..2e6d738ea 100644
--- a/src/engine/platform/ym2610shared.h
+++ b/src/engine/platform/ym2610shared.h
@@ -364,7 +364,7 @@ class DivPlatformYM2610Base: public DivPlatformOPN {
     }
 
     DivPlatformYM2610Base(int ext, int psg, int adpcmA, int adpcmB, int chanCount):
-      DivPlatformOPN(ext,psg,adpcmA,adpcmB,chanCount,9440540.0, 72, 32) {}
+      DivPlatformOPN(ext,psg,adpcmA,adpcmB,chanCount,9440540.0, 72, 32, false, 16) {}
 };
 
 #endif