Usher 6371 or 6381? Coffee table blocks woofer?

"Is that bad for their performance?"

Usually yes. In this location you will most often get boomy bass and a very flat sound stage effect. If you must put speakers very close to a rear wall I would suggest that you consider smaller monitor types which can use the bass reinforcement provided by the wall.

Yes....due to the rear port, you will likely have bass boom so close to the wall. I experimented placing the Ushers in many different positions. To really get the best from them you want to be away from the wall. In my room, I needed at least 27" from the front wall to the rear of the speaker,( 32" is optimal for me) otherwise the upper bass is excessive and the soundstage and center image collapses and becomes rather compressed or flat. All because of wall reienforcement.Like most good speakers, the Ushers will do best further out into the room.

A smaller stand mounted monitor can have suprisingly good bass and may be a better choice due to your constraints...Look for a monitor with front ports as opposed to rear or a sealed enclosure type if close wall placement is a must.- Ken

I love my B.E.20,s with 4 N,H,T 12 inch subs. But its a pain when your house has long stairs and you need to shift

Paul Klipch, must have been a loony, I had a pair of his corner horns for 15 years and had them pushed hard up into the corners. I enjoyed great sounds for all those years,and regretted selling them.The Theil 3.6,s were always to bright and I found the Usher B.E. 20,s much better, I coupled them to 2 N.H.T 12 inch x 2 subs,even though Usher warns that the B E,s can overload with bass. A couple of bass traps in the corners can do wonders if bass gets too much, but yes 2 to 3 feet from rear wall and slight toe in is good advice. Use the torch method to find the sweet spots.