I don't feel like re-inventing the wheel at this time,
so here are some useful references.     -temper

Check Allakhazam's Magical Realm for quest information. Access to the Theater of Blood/Plane of Music Access to Deathknell, Tower of Dissonance
Check Samanna's Reference Desk for full information. Detailed Walkthrough -- Check List

Level Based Zone Access - Apr 17, 2008
At level 68 you get the Harmonic Dissonance progression AA.
Theater of Blood and Deathknell are openly accessible at level 72.
/sigh