diff --git a/src/audio/SDL_audio.c b/src/audio/SDL_audio.c
--- a/src/audio/SDL_audio.c
+++ b/src/audio/SDL_audio.c
@@ -1413,7 +1413,13 @@
         id = open_audio_device(NULL, 0, desired, obtained,
                                SDL_AUDIO_ALLOW_ANY_CHANGE, 1);
     } else {
-        id = open_audio_device(NULL, 0, desired, NULL, 0, 1);
+        SDL_AudioSpec _obtained;
+        SDL_zero(_obtained);
+        id = open_audio_device(NULL, 0, desired, &_obtained, 0, 1);
+        /* On successful open, copy calculated values into 'desired'. */
+        if (id > 0) {
+            desired->size = _obtained.size;
+        }
     }
 
     SDL_assert((id == 0) || (id == 1));