diff --git a/src/engine/platform/snes.cpp b/src/engine/platform/snes.cpp
index 5bd28b194..e99db88a6 100644
--- a/src/engine/platform/snes.cpp
+++ b/src/engine/platform/snes.cpp
@@ -284,9 +284,9 @@ int DivPlatformSNES::dispatch(DivCommand c) {
         if (chan[c.chan].insChanged) {
           if (chan[c.chan].wave<0) {
             chan[c.chan].wave=0;
-            chan[c.chan].ws.setWidth(chan[c.chan].wtLen);
-            chan[c.chan].ws.changeWave1(chan[c.chan].wave);
           }
+          chan[c.chan].ws.setWidth(chan[c.chan].wtLen);
+          chan[c.chan].ws.changeWave1(chan[c.chan].wave);
         }
         chan[c.chan].ws.init(ins,chan[c.chan].wtLen,15,chan[c.chan].insChanged);
       } else {
diff --git a/src/gui/debugWindow.cpp b/src/gui/debugWindow.cpp
index 2c507bb47..a8f750087 100644
--- a/src/gui/debugWindow.cpp
+++ b/src/gui/debugWindow.cpp
@@ -382,9 +382,9 @@ void FurnaceGUI::drawDebug() {
     }
     if (ImGui::TreeNode("ADSR Test Area")) {
       static int tl, ar, dr, d2r, sl, rr, sus, egt, algOrGlobalSus, instType;
-      static float maxArDr, maxTl;
+      static float maxArDr, maxTl, maxRr;
       ImGui::Text("This window was done out of frustration");
-      drawFMEnv(tl,ar,dr,d2r,rr,sl,sus,egt,algOrGlobalSus,maxTl,maxArDr,ImVec2(200.0f*dpiScale,100.0f*dpiScale),instType);
+      drawFMEnv(tl,ar,dr,d2r,rr,sl,sus,egt,algOrGlobalSus,maxTl,maxArDr,maxRr,ImVec2(200.0f*dpiScale,100.0f*dpiScale),instType);
 
       ImGui::InputInt("tl",&tl);
       ImGui::InputInt("ar",&ar);
@@ -398,6 +398,7 @@ void FurnaceGUI::drawDebug() {
       ImGui::InputInt("instType",&instType);
       ImGui::InputFloat("maxArDr",&maxArDr);
       ImGui::InputFloat("maxTl",&maxTl);
+      ImGui::InputFloat("maxRr",&maxRr);
       ImGui::TreePop();
     }
     if (ImGui::TreeNode("User Interface")) {
diff --git a/src/gui/gui.h b/src/gui/gui.h
index 76a25efd4..c4b1005da 100644
--- a/src/gui/gui.h
+++ b/src/gui/gui.h
@@ -1617,7 +1617,7 @@ class FurnaceGUI {
   void drawSSGEnv(unsigned char type, const ImVec2& size);
   void drawWaveform(unsigned char type, bool opz, const ImVec2& size);
   void drawAlgorithm(unsigned char alg, FurnaceGUIFMAlgs algType, const ImVec2& size);
-  void drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr, unsigned char d2r, unsigned char rr, unsigned char sl, unsigned char sus, unsigned char egt, unsigned char algOrGlobalSus, float maxTl, float maxArDr, const ImVec2& size, unsigned short instType);
+  void drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr, unsigned char d2r, unsigned char rr, unsigned char sl, unsigned char sus, unsigned char egt, unsigned char algOrGlobalSus, float maxTl, float maxArDr, float maxRr, const ImVec2& size, unsigned short instType);
   void drawGBEnv(unsigned char vol, unsigned char len, unsigned char sLen, bool dir, const ImVec2& size);
   void drawSysConf(int chan, DivSystem type, unsigned int& flags, bool modifyOnChange);
   void kvsConfig(DivInstrument* ins);
diff --git a/src/gui/insEdit.cpp b/src/gui/insEdit.cpp
index 2ab022ddc..a8fbf48dc 100644
--- a/src/gui/insEdit.cpp
+++ b/src/gui/insEdit.cpp
@@ -1070,7 +1070,7 @@ void FurnaceGUI::drawAlgorithm(unsigned char alg, FurnaceGUIFMAlgs algType, cons
   }
 }
 
-void FurnaceGUI::drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr, unsigned char d2r, unsigned char rr, unsigned char sl, unsigned char sus, unsigned char egt, unsigned char algOrGlobalSus, float maxTl, float maxArDr, const ImVec2& size, unsigned short instType) {
+void FurnaceGUI::drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr, unsigned char d2r, unsigned char rr, unsigned char sl, unsigned char sus, unsigned char egt, unsigned char algOrGlobalSus, float maxTl, float maxArDr, float maxRr, const ImVec2& size, unsigned short instType) {
   ImDrawList* dl=ImGui::GetWindowDrawList();
   ImGuiWindow* window=ImGui::GetCurrentWindow();
 
@@ -1096,7 +1096,7 @@ void FurnaceGUI::drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr,
     float arPos=float(maxArDr-ar)/maxArDr; //peak of AR, start of DR
     float drPos=arPos+((sl/15.0)*(float(maxArDr-dr)/maxArDr)); //end of DR, start of D2R
     float d2rPos=drPos+(((15.0-sl)/15.0)*(float(31.0-d2r)/31.0)); //End of D2R
-    float rrPos=(float(15-rr)/15.0); //end of RR
+    float rrPos=(float(maxRr-rr)/float(maxRr)); //end of RR
 
     //shrink all the x positions horizontally
     arPos/=2.0;
@@ -1125,7 +1125,7 @@ void FurnaceGUI::drawFMEnv(unsigned char tl, unsigned char ar, unsigned char dr,
       //addAALine(dl,pos3,posSLineVEnd,colorS); //draw vert. line through sustain level
       addAALine(dl,pos1,pos2,color); //A
       addAALine(dl,pos2,posDecayRate0Pt,color); //Line from A to end of graph
-    } else if (d2r==0.0 || (instType==DIV_INS_OPL && sus==1.0) || (instType==DIV_INS_OPLL && egt!=0.0)) { //envelope stays at the sustain level forever
+    } else if (d2r==0.0 || ((instType==DIV_INS_OPL || instType==DIV_INS_SNES) && sus==1.0) || (instType==DIV_INS_OPLL && egt!=0.0)) { //envelope stays at the sustain level forever
       dl->AddTriangleFilled(posRStart,posREnd,pos1,colorS); //draw release as shaded triangle behind everything
       addAALine(dl,pos3,posSLineHEnd,colorR); //draw horiz line through sustain level
       addAALine(dl,pos3,posSLineVEnd,colorR); //draw vert. line through sustain level
@@ -2393,7 +2393,7 @@ void FurnaceGUI::drawInsEdit() {
                     }
 
                     ImGui::TableNextColumn();
-                    drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPL_DRUMS || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,op.sus,op.ssgEnv&8,ins->fm.alg,maxTl,maxArDr,ImVec2(ImGui::GetContentRegionAvail().x,sliderHeight),ins->type);
+                    drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPL_DRUMS || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,op.sus,op.ssgEnv&8,ins->fm.alg,maxTl,maxArDr,15,ImVec2(ImGui::GetContentRegionAvail().x,sliderHeight),ins->type);
 
                     if (settings.separateFMColors) {
                       popAccentColors();
@@ -2810,7 +2810,7 @@ void FurnaceGUI::drawInsEdit() {
                       if (ins->type==DIV_INS_OPZ) {
                         envHeight-=ImGui::GetFrameHeightWithSpacing()*2.0f;
                       }
-                      drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPL_DRUMS || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,op.sus,op.ssgEnv&8,ins->fm.alg,maxTl,maxArDr,ImVec2(ImGui::GetContentRegionAvail().x,envHeight),ins->type);
+                      drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPL_DRUMS || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,op.sus,op.ssgEnv&8,ins->fm.alg,maxTl,maxArDr,15,ImVec2(ImGui::GetContentRegionAvail().x,envHeight),ins->type);
 
                       if (ins->type==DIV_INS_OPZ) {
                         ImGui::Separator();
@@ -3003,7 +3003,7 @@ void FurnaceGUI::drawInsEdit() {
                     }
 
                     //52.0 controls vert scaling; default 96
-                    drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPL_DRUMS || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,op.sus,op.ssgEnv&8,ins->fm.alg,maxTl,maxArDr,ImVec2(ImGui::GetContentRegionAvail().x,52.0*dpiScale),ins->type);
+                    drawFMEnv(op.tl&maxTl,op.ar&maxArDr,op.dr&maxArDr,(ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPL_DRUMS || ins->type==DIV_INS_OPLL)?((op.rr&15)*2):op.d2r&31,op.rr&15,op.sl&15,op.sus,op.ssgEnv&8,ins->fm.alg,maxTl,maxArDr,15,ImVec2(ImGui::GetContentRegionAvail().x,52.0*dpiScale),ins->type);
                     //P(CWSliderScalar(FM_NAME(FM_AR),ImGuiDataType_U8,&op.ar,&_ZERO,&_THIRTY_ONE)); rightClickable
                     if (ImGui::BeginTable("opParams",2,ImGuiTableFlags_SizingStretchProp)) {
                       ImGui::TableSetupColumn("c0",ImGuiTableColumnFlags_WidthStretch,0.0); \
@@ -3650,7 +3650,7 @@ void FurnaceGUI::drawInsEdit() {
             ImGui::TableNextColumn();
             P(CWVSliderScalar("##Release",sliderSize,ImGuiDataType_U8,&ins->c64.r,&_ZERO,&_FIFTEEN));
             ImGui::TableNextColumn();
-            drawFMEnv(0,16-ins->c64.a,16-ins->c64.d,15-ins->c64.r,15-ins->c64.r,15-ins->c64.s,0,0,0,15,16,ImVec2(ImGui::GetContentRegionAvail().x,sliderSize.y),ins->type);
+            drawFMEnv(0,16-ins->c64.a,16-ins->c64.d,15-ins->c64.r,15-ins->c64.r,15-ins->c64.s,0,0,0,15,16,15,ImVec2(ImGui::GetContentRegionAvail().x,sliderSize.y),ins->type);
 
             ImGui::EndTable();
           }
@@ -3764,11 +3764,16 @@ void FurnaceGUI::drawInsEdit() {
               P(ImGui::Checkbox("Use wavetable (Amiga/SNES only)",&ins->amiga.useWave));
               if (ins->amiga.useWave) {
                 int len=ins->amiga.waveLen+1;
+                int origLen=len;
                 if (ImGui::InputInt("Width",&len,2,16)) {
                   if (ins->type==DIV_INS_SNES) {
                     if (len<16) len=16;
                     if (len>256) len=256;
-                    ins->amiga.waveLen=(len&(~15))-1;
+                    if (len>origLen) {
+                      ins->amiga.waveLen=((len+15)&(~15))-1;
+                    } else {
+                      ins->amiga.waveLen=(len&(~15))-1;
+                    }
                   } else {
                     if (len<2) len=2;
                     if (len>256) len=256;
@@ -4006,7 +4011,7 @@ void FurnaceGUI::drawInsEdit() {
               ImGui::TableNextColumn();
               P(CWVSliderScalar("##Rate Correction",sliderSize,ImGuiDataType_U8,&ins->multipcm.rc,&_ZERO,&_FIFTEEN));
               ImGui::TableNextColumn();
-              drawFMEnv(0,ins->multipcm.ar,ins->multipcm.d1r,ins->multipcm.d2r,ins->multipcm.rr,ins->multipcm.dl,0,0,0,127,15,ImVec2(ImGui::GetContentRegionAvail().x,sliderSize.y),ins->type);
+              drawFMEnv(0,ins->multipcm.ar,ins->multipcm.d1r,ins->multipcm.d2r,ins->multipcm.rr,ins->multipcm.dl,0,0,0,127,15,15,ImVec2(ImGui::GetContentRegionAvail().x,sliderSize.y),ins->type);
               ImGui::EndTable();
             }
             if (ImGui::BeginTable("MultiPCMLFOParams",3,ImGuiTableFlags_SizingStretchSame)) {
@@ -4062,7 +4067,7 @@ void FurnaceGUI::drawInsEdit() {
               ImGui::TableNextColumn();
               P(CWVSliderScalar("##Release",sliderSize,ImGuiDataType_U8,&ins->snes.r,&_ZERO,&_THIRTY_ONE));
               ImGui::TableNextColumn();
-              drawFMEnv(0,ins->snes.a+1,1+ins->snes.d*2,ins->snes.r,ins->snes.r,(14-ins->snes.s*2),(ins->snes.r==0),0,0,7,16,ImVec2(ImGui::GetContentRegionAvail().x,sliderSize.y),ins->type);
+              drawFMEnv(0,ins->snes.a+1,1+ins->snes.d*2,ins->snes.r,ins->snes.r,(14-ins->snes.s*2),(ins->snes.r==0 || ins->snes.sus),0,0,7,16,31,ImVec2(ImGui::GetContentRegionAvail().x,sliderSize.y),ins->type);
 
               ImGui::EndTable();
             }