diff --git a/src/ABC.cpp b/src/ABC.cpp
index 65b3750..5cd8dfd 100644
--- a/src/ABC.cpp
+++ b/src/ABC.cpp
@@ -1,4 +1,5 @@
 #include "Befaco.hpp"
+#include "dsp/functions.hpp"
 
 
 struct ABC : Module {
diff --git a/src/SpringReverb.cpp b/src/SpringReverb.cpp
index 71da275..1369f44 100644
--- a/src/SpringReverb.cpp
+++ b/src/SpringReverb.cpp
@@ -1,5 +1,6 @@
 #include <string.h>
 #include "Befaco.hpp"
+#include "dsp/functions.hpp"
 #include "dsp/samplerate.hpp"
 #include "dsp/ringbuffer.hpp"
 #include "dsp/filter.hpp"