[shalym]

Originally Posted by murraypaul

A quick Google suggests that:
- Format 4 is fixed at 32kb/s, 22kHz, mono, while enhanced is more flexible, with 32-128kb/s, 22 or 44kHz, mono or stereo. (In practice seems to be 64kb/s, 22kHz)
- Enhanced is AAC, Format 4 is MP3
- Enhanced generally uses twice as much space.

Some detail here: https://audible.custhelp.com/app/ans...st-suits-me%3F

...and don't forget,

Originally Posted by CRussel

The new format is actually much easier to liberate.

Shari