Thanks to Jonathan Lange, a Librivox Volunteer, the entire Book of Concord is now available in audio format. You can find it on the sidebar on the Book of Concord website in the top segment, “BoC on Audio”. The translation used is the Triglotta, which is the same one used on the Book of Concord website.
The recordings are public domain and are organized on archive.org in different formats. They can be put on your smartphone or mp3 player so you can listen to the BoC anytime.