diff --git a/src/output/jack_output_plugin.c b/src/output/jack_output_plugin.c
index 7f65c7852..628594a15 100644
--- a/src/output/jack_output_plugin.c
+++ b/src/output/jack_output_plugin.c
@@ -47,7 +47,7 @@ struct jack_data {
 
 	/* configuration */
 	char *output_ports[2];
-	int ringbuffer_size;
+	size_t ringbuffer_size;
 
 	/* the current audio format */
 	struct audio_format audio_format;