--- a/libmp3lame/set_get.c
+++ b/libmp3lame/set_get.c
@@ -93,7 +93,7 @@
 {
     if (is_lame_global_flags_valid(gfp)) {
         /* default = 2 */
-        if (2 < num_channels || 0 >= num_channels) {
+        if (1 != num_channels && 2 != num_channels) {
             return -1;  /* we don't support more than 2 channels */
         }
         gfp->num_channels = num_channels;