13 Audio
Directly pasting-in link to audio (librivox/internet archive) mp3 file:
(note: mp3 files from Librivox/internet archive can’t be uploaded to the media library, generates a “file type not permitted error”)
Uploaded test file (m4a) (10 seconds, just tapping sounds):
Same test file, on pb.com
Audio from Soundcloud using embed shortcode