diff --git a/libretro-common/audio/audio_mixer.c b/libretro-common/audio/audio_mixer.c
index a274989be4..7d8afb25ab 100644
--- a/libretro-common/audio/audio_mixer.c
+++ b/libretro-common/audio/audio_mixer.c
@@ -122,6 +122,7 @@ struct audio_mixer_sound
       } mod;
 #endif
    } types;
+   void* user_data;
 };
 
 struct audio_mixer_voice