diff --git a/src/dsp.c b/src/dsp.c
index ef6ae91..feb2d75 100755
--- a/src/dsp.c
+++ b/src/dsp.c
@@ -23,6 +23,7 @@
 #include <math.h>
 
 #include "filter.h"
+#include "filtercoeff.h" 
 
 // In case your C compiler is so old that Pi hadn't been invented yet
 #ifndef M_PI