Audio 6.1 should be allowed now (see #4974)
diff --git a/src/audio/SDL_audio.c b/src/audio/SDL_audio.c
index 5d86976..fd8e6da 100644
--- a/src/audio/SDL_audio.c
+++ b/src/audio/SDL_audio.c
@@ -1268,6 +1268,7 @@ prepare_audiospec(const SDL_AudioSpec * orig, SDL_AudioSpec * prepared)
case 2: /* Stereo */
case 4: /* Quadrophonic */
case 6: /* 5.1 surround */
+ case 7: /* 6.1 surround */
case 8: /* 7.1 surround */
break;
default: