diff --git a/lib_rend/lib_rend.c b/lib_rend/lib_rend.c
index 666bea3169ef12e2cf94d472ee5b7386665f0e84..e6acb212a4cb1d3a717b8198de1b810d5cd773c3 100644
--- a/lib_rend/lib_rend.c
+++ b/lib_rend/lib_rend.c
@@ -8435,7 +8435,11 @@ static ivas_error initMasaExtRenderer(
         return error;
     }
 
-    if ( ( error = getAudioConfigNumChannels( outConfig, &hMasaExtRend->nchan_output ) ) != IVAS_ERR_OK )
+    if ( outConfig == IVAS_AUDIO_CONFIG_LS_CUSTOM )
+    {
+        hMasaExtRend->nchan_output = inputMasa->base.ctx.pCustomLsOut->num_spk + inputMasa->base.ctx.pCustomLsOut->num_lfe;
+    }
+    else if ( ( error = getAudioConfigNumChannels( outConfig, &hMasaExtRend->nchan_output ) ) != IVAS_ERR_OK )
     {
         return error;
     }