Just saw the Irish Examiner's review today and they give good info about the audio;
"The result is some seriously meaty audio straight from the device, which manages to remain clear even at the highest volume. It’s great for watching YouTube videos or sharing a bit of music, just don’t do it on the bus as we will hate you for it.
HTC is also bringing 24-bit audio to the party and offering Hi-Res tunes for those with the right setup. Upscaling is possible for your existing tracks and the built-in amplifier will deliver it via your own phones or the high quality pair in the box.
Music, movies, podcasts, whatever – it all just sounds better with this set up. And you can get a unique experience with the Personal Audio Profile system. This plays a series of tones at different frequencies to find out exactly how you hear, and adjusts your profile accordingly.
If you’re into music this handset could see you ditch your dedicated player, especially for Hi-Res offerings."