About Audio Formats
Understanding Audio Formats and File Size
Our audio formats are based on the quality of the audio file.  Audio files are compressed so that they download faster and take up less space on your computer's hard drive or in your listening device's memory. In general, less compression means higher quality audio, but also means a larger file and longer download.

We offer a variety of formats so that you can choose the right quality and file size for your computer or listening device. If you're not sure what format to choose, please review the information below.
Audio Format
Sound Quality
File size for 1 hr of audio
Download time per hour
(high speed connection)
Download time per hour
(56K modem)
Listen to a sample:
Extreme Measures
2
AM radio*
3.7MB
20 sec
9 min
3
FM radio*
7.2MB
40 sec
17 mins
4
MP3*
14.4MB
1m 19s
35 mins
NEW!
Audible Enhanced Audio
CD*
28.8MB
2m 37s
1h 9m
* Sound quality is similar to.
Compatible Devices
Some formats are compatible only with certain listening devices. For more information on which formats work with each device, please visit our Device Centre.