Why Your Next Audiobook Should Be in AAC Format (And Where to Find Them)

Because it's more efficient, an AAC file can be smaller than an MP3 of the same quality. That means more space for your "to-listen" pile.

Often used for music, but essentially the same audio technology. .aac: The raw audio stream itself. The Benefits of Listening in AAC

Even at lower bitrates, AAC preserves the nuances of a narrator's voice better than MP3. You get that "in the room" feeling without the digital "fuzz".

The standard "audiobook" format (widely used by Apple). It supports chapters and bookmarks so you never lose your place.