diff --git a/lib_rend/lib_rend.c b/lib_rend/lib_rend.c
index 26ac7c731ea202dcac80475cc600b88ec619ec47..8a7a5a56e138b08daada790cdc8fec495327a14b 100644
--- a/lib_rend/lib_rend.c
+++ b/lib_rend/lib_rend.c
@@ -6912,7 +6912,11 @@ 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;
     }