diff --git a/include/mixer.h b/include/mixer.h
index b6b11f30d..a6b29bc79 100644
--- a/include/mixer.h
+++ b/include/mixer.h
@@ -267,7 +267,7 @@ public:
 	// audio-buffer-mgm
 	void FASTCALL bufferToPort( const sampleFrame * _buf,
 					const fpab_t _frames,
-					const fpab_t _framesAhead,
+					const f_cnt_t _framesAhead,
 					const volumeVector & _volumeVector,
 							audioPort * _port );
 
diff --git a/src/core/mixer.cpp b/src/core/mixer.cpp
index 83936e418..9b12e94c6 100644
--- a/src/core/mixer.cpp
+++ b/src/core/mixer.cpp
@@ -352,7 +352,7 @@ void FASTCALL mixer::clearAudioBuffer( surroundSampleFrame * _ab,
 
 void FASTCALL mixer::bufferToPort( const sampleFrame * _buf,
 					const fpab_t _frames,
-					const fpab_t _frames_ahead,
+					const f_cnt_t _frames_ahead,
 					const volumeVector & _volume_vector,
 						audioPort * _port )
 {