diff --git a/src/wildmidi.c b/src/wildmidi.c
index 55f1d3f4..9ae39723 100644
--- a/src/wildmidi.c
+++ b/src/wildmidi.c
@@ -1121,7 +1121,7 @@ int main(int argc, char **argv) {
 			rate = res;
 			break;
 		case 'b': /* Reverb */
-			mixer_options ^= WM_MO_REVERB;
+			mixer_options |= WM_MO_REVERB;
 			break;
 		case 'm': /* Master Volume */
 			master_volume = (unsigned char) atoi(optarg);