Engadget did a detailed look into the Dr.Dre thing
HTC Sensation XE with Beats Audio review -- Engadget
Summary: aka its all a gimmick. Just an ordinary EQ profile tweaked to their headsets and certain types of music. If you want real quality music you need a phone with a good DAC, no amount of software will fix generic hardware.
If audio is all you care about and don't plan on activating the phone, then see if someone will exchange your evo for an epic/vibrant/fascinate/captivate/mesmerize, then flash a voodoo sound compatible kernel and get voodoo sound on the market. Then you can hear the magic of Wolfson's WM8994 DAC at work...