diff --git a/src/fm_mpx.h b/src/fm_mpx.h
index 7f53ec6..d939d5c 100644
--- a/src/fm_mpx.h
+++ b/src/fm_mpx.h
@@ -17,8 +17,8 @@
  */
 
 /* MPX */
-#define NUM_MPX_FRAMES_IN	512
-#define NUM_MPX_FRAMES_OUT	(NUM_MPX_FRAMES_IN * 2)
+#define NUM_MPX_FRAMES_IN	256
+#define NUM_MPX_FRAMES_OUT	(NUM_MPX_FRAMES_IN * 4)
 /*
  * The sample rate at which the MPX generation runs at
  */