The popularity of the digital subscription model continues to grow with the announcement that e-book subscription service Scribd will now offer unlimited access to more than 30,000 audiobooks.

Scribd v-p Julie Haddon said the agreement will provide access to audiobook titles from Blackstone, HarperCollins, Scholastic and Naxos and other houses. She emphasized that the audiobook titles are being made all available to all Scribd subscription members under their current plan for $8.99 a month, with no additional charge. The audiobooks can be listened to online or offline and include new releases like How To Build A Girl by Gaitlin Moran, and classic works like The Savage Detectives by Roberto Bolano.

The audiobook titles include frontlist titles, unusual for e-book subscription, as well as bestsellers. Many of the audiobooks added to the Scribd service are available even when their prose e-book editions are not.

Audiobook titles are available for use on Android, Kindle Fire, Nook tablets and web browsers and will be available to iOS users in the next few days. Scribd has also integrated audiobooks into its recently launched browsing/recommendation program, which offers tiers of recommendations provided by Scribd editors as well as from computer algorithms.

Haddon also noted a number of features offered via the audio service including the ability to listen offline as well as online; audio bookmarks, multiple playback speeds and Bluetooth functionality. In addition, Scribd plans to add features that will allow a user to toggle between the prose e-book and the audiobook pages and synch the two spots when the listener stops

The deal also marks HarperCollins continuing efforts to explore new digital business models for distributing its titles. Chantal Restivo-Alessi, chief digital officer, HarperCollins said “Audio is a growing category and one that needs additional distribution channels. By making our audiobooks available through Scribd, we’re opening up a much a wider market for our authors’ works.”

Trip Adler, co-founder and CEO of Scribd, noted that the addition of audiobooks “has been one of our most popular requests" from subscribers, calling audiobooks "a natural extension of Scribd’s existing content offering."