diff --git a/src/audioOutputs/audioOutput_jack.c b/src/audioOutputs/audioOutput_jack.c
index 955eccd0b..8818bb739 100644
--- a/src/audioOutputs/audioOutput_jack.c
+++ b/src/audioOutputs/audioOutput_jack.c
@@ -27,7 +27,7 @@
 #include <jack/types.h>
 #include <jack/ringbuffer.h>
 
-size_t sample_size = sizeof(jack_default_audio_sample_t);
+static const size_t sample_size = sizeof(jack_default_audio_sample_t);
 
 typedef struct _JackData {
 	/* configuration */