diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index 2399eb35..02dfefd1 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -458,13 +458,13 @@ class DivDispatch {
      * get minimum chip clock.
      * @return clock in Hz, or 0 if custom clocks are not supported.
      */
-    virtual unsigned int getClockRangeMin();
+    virtual int getClockRangeMin();
 
     /**
      * get maximum chip clock.
      * @return clock in Hz, or 0 if custom clocks are not supported.
      */
-    virtual unsigned int getClockRangeMax();
+    virtual int getClockRangeMax();
 
     /**
      * set the chip flags.
diff --git a/src/engine/platform/abstract.cpp b/src/engine/platform/abstract.cpp
index 28974062..bd56efb8 100644
--- a/src/engine/platform/abstract.cpp
+++ b/src/engine/platform/abstract.cpp
@@ -97,11 +97,11 @@ bool DivDispatch::getWantPreNote() {
   return false;
 }
 
-unsigned int DivDispatch::getClockRangeMin() {
+int DivDispatch::getClockRangeMin() {
   return MIN_CUSTOM_CLOCK;
 }
 
-unsigned int DivDispatch::getClockRangeMax() {
+int DivDispatch::getClockRangeMax() {
   return MAX_CUSTOM_CLOCK;
 }