diff --git a/src/gui/insEdit.cpp b/src/gui/insEdit.cpp
index f6813fd3..e3a580c2 100644
--- a/src/gui/insEdit.cpp
+++ b/src/gui/insEdit.cpp
@@ -4420,7 +4420,10 @@ void FurnaceGUI::drawInsEdit() {
           }
           if (ImGui::InputInt("Offset##WAVEPOS",&ins->n163.wavePos,1,16)) { PARAMETER
             if (ins->n163.wavePos<0) ins->n163.wavePos=0;
-            if (ins->n163.wavePos>236) ins->n163.wavePos=236;
+            if (ins->n163.wavePos>240) ins->n163.wavePos=240;
+                if (ins->n163.wavePos + ins->n163.waveLen > 240) {
+                ins->n163.wavePos -= ins->n163.waveLen;
+            }
           }
           if (ImGui::InputInt("Length##WAVELEN",&ins->n163.waveLen,4,16)) { PARAMETER
              int n163origLen = ins->n163.waveLen;