@rhljazz Thanks for the suggestions. The absorption panels behind the right speaker are used to cover windows. I wanted symmetry, so I put panels behind the left speaker too.
@tomic601 Thanks, Jim! I'm very happy with the pairing. Nevertheless, upgraditis has me considering the M5-HP crossover instead of the X1s I'm using now.
Have you considered removing the large absorption panels next to the left speaker? IME a live end (speakers) dead end room usually sounds terrific. Might try a pair of tube traps in the speaker corners. They can be rotated to provide a mix of absorption/reflection. Nice selection of gear.