Music playback is about as basic as one would expect from an MP3 player with no screen, although the Split Thump offers a fair amount of features. You can shuffle tracks and designate an Overdrive song (meant to be an up-tempo track for motivation during activity) that can be accessed immediately by pressing the Play/Pause and Fast-Forward keys at the same time. The player is compatible with both Mac and Windows, with syncing handled via drag and drop or using any of several jukeboxes (iTunes and Windows Media Player among them). Supported audio formats include MP3, unprotected AAC, Audible, and both unprotected and protected WMA (DRM 9 only--no subscriptions). If you use the drag-and-drop method to transfer, you can even create playlists (as folders) and navigate through them by pressing the Up or Down Volume buttons while in Pause mode.
As with previous Thumps, the Split doesn't impress with its rated 7-hour battery life, but that's still plenty of time for most of the activities for which the glasses are made. A notable exception is a day on the slopes; this reviewer had the Thump 2s peter out at the end of a full day of boarding. Still, there's no denying the usefulness of having eye protection and music playback combined into one lightweight device when faced with a day on the snow.
Audio quality isn't stellar, but neither is it completely disappointing. Hip-hop tracks sounded a bit bright and lacking in depth for our tastes, but rock tracks sounded quite good. The low end is lacking in boom, but you can get some bass if you really shove the earbuds in. The high end, however, was crystal clear and detailed across genres. All in all, music seemed to be lacking a bit in warmth, but in the final analysis it was definitely passable for the convenience of having an MP3 player integrated into a pair of sunglasses.