diff --git a/src/mame/audio/polepos.cpp b/src/mame/audio/polepos.cpp
index 0b52d0d753f..ffedee5c283 100644
--- a/src/mame/audio/polepos.cpp
+++ b/src/mame/audio/polepos.cpp
@@ -61,19 +61,6 @@ struct filter_state
 	filter_real xprev[FILTER_ORDER_MAX];
 };
 
-#if 0
-/* Insert a value in the filter state */
-static inline void filter_insert(filter* f, filter_state* s, filter_real x) {
-	/* next state */
-	++s->prev_mac;
-	if (s->prev_mac >= f->order)
-		s->prev_mac = 0;
-
-	/* set x[0] */
-	s->xprev[s->prev_mac] = x;
-}
-#endif
-
 /* Filter types */
 #define FILTER_LOWPASS      0
 #define FILTER_HIGHPASS     1