diff --git a/src/engine/platform/ay.h b/src/engine/platform/ay.h
index 7d6b27e14..db08f8ee2 100644
--- a/src/engine/platform/ay.h
+++ b/src/engine/platform/ay.h
@@ -148,8 +148,8 @@ class DivPlatformAY8910: public DivDispatch {
     short pendingWrites[16];
     unsigned char ayNoisePeriod;
     unsigned char ayEnvMode;
-    unsigned short ayOldEnvPeriod;
-    unsigned short ayEnvPeriod;
+    unsigned int ayOldEnvPeriod;
+    unsigned int ayEnvPeriod;
     short ayEnvSlideLow;
     short ayEnvSlide;