Review: HTC Touch Diamond
Music is just another selection in the TouchFLO UI. The default view shows you a set of album covers from your library, which you can shuffle through (sort of like CoverFlow on the iPhone). There is also a large button at the top that takes you to the Sprint Music Store. I bought a few tracks from the store. They downloaded just fine, but you only have a two-week window to download a copy to your PC as well.
The Diamond can sync with Windows Media Player, or be used as a mass storage device. This lets you drag and drop music files from your computer and transfer them directly to the phone's internal memory. Transferring music this way was reasonably fast.
With the music icon selected, the left soft key is what you need to press to get into your library. HTC has dressed up Windows Media Player a little bit, but the basic menu architecture is the same. You have to choose from artists, albums, songs, playlists, etc. Pick what you want and press play. You'll shoot back out to the main screen, and you'll see the ablum cover art and some basic on-screen controls to pause the music and skip forward/backward tracks.
Alternately, you can open Windows Media Player itself from the Diamond's menus and use the regular player. The regular player offers a bit more choices for customizing control, but it doesn't have an equalizer to adjust the sound.
Music playback sounded good through headphones, though it wasn't stellar. I already mentioned the awkwardness of the headphone adapter, but I'll reiterate the point here. Using it stinks.