Flat, grainy, strident, shouty, raw. Incohesive, no emotional interest, doesn't let go of the music. These are all words I jotted down to describe how my new Odysseys sounded before they burned in.
Now they are round, dimensional, meaty, open, sweet, incisive. The music soars and fills the soundstage, into the room.
Have faith and patience. You will be rewarded.