diff --git a/lib_rend/lib_rend_fx.c b/lib_rend/lib_rend_fx.c
index 278046d083f61875eafd1a08da8dfd7ce114e75e..6150926692003cac265024869a6a85308197050d 100644
--- a/lib_rend/lib_rend_fx.c
+++ b/lib_rend/lib_rend_fx.c
@@ -8050,7 +8050,12 @@ static ivas_error initMasaExtRenderer(
         return error;
     }
 
-    IF( NE_32( ( error = getAudioConfigNumChannels( outConfig, &hMasaExtRend->nchan_output ) ), IVAS_ERR_OK ) )
+    IF( EQ_32( outConfig, IVAS_AUDIO_CONFIG_LS_CUSTOM ) )
+    {
+        hMasaExtRend->nchan_output = add( inputMasa->base.ctx.pCustomLsOut->num_spk, inputMasa->base.ctx.pCustomLsOut->num_lfe );
+        move16();
+    }
+    ELSE IF( NE_32( ( error = getAudioConfigNumChannels( outConfig, &hMasaExtRend->nchan_output ) ), IVAS_ERR_OK ) )
     {
         return error;
     }