"More than 20 percent of Audible customers already use Audible's iPhone app on the iPad" was the stat supplied by Audible's Vice President of Mobile Apps, as the audio book company deployed an optimized update specifically for iPad use.

Previous iterations of the app had been designed to support the smaller screens of the iPhone and iPod Touch, but the February 20 update brings in layouts for the iPad and iPad Mini.

It's a free app for Amazon's Audible service, which packs in paid-for audiobooks and an optional subscription-based scheme.

While Audible looks to supplant Apple's built-in app as a preferred method for audio book consumption, others offer alternative routes into the modern aural storytelling movement.

Bardowl sets itself up as a "Spotify for audiobooks," with unlimited access to streamed audio, while the members of sites like Project Gutenberg and LibriVox continue to contribute free readings of classic and copyright-free works.