diff --git a/src/pifmrds/fm_mpx.c b/src/pifmrds/fm_mpx.c
index 35415b3..11d6846 100644
--- a/src/pifmrds/fm_mpx.c
+++ b/src/pifmrds/fm_mpx.c
@@ -326,7 +326,7 @@ int fm_mpx_get_samples(float *mpx_buffer, int drds, float compressor_decay, floa
             } else {
                 mpx_buffer[i] =  
                     mpx_buffer[i] +    // RDS data samples are currently in mpx_buffer :to be Remove in NFM
-                    9.0*(out_left+out_right);      // Unmodulated monophonic signal
+                    9.0*(out_left+out_right);      // Unmodulated L+R signal
             }
         }
         else