I recall being at a gathering of audiophiles at the home of an audio reviewer. We were well acquainted with the excellent acoustics of the room in which many of the items that he reviewed were auditioned and all of us were surprised at how poorly everything sounded during our session. The host had generously replaced the hard surfaced chairs on which we normally sat with a beautiful upholstered couch. We finally realized that the only change to the room was the replacement of the chairs with the couch. Together, we removed the couch, and voila !! After listening for an hour or so, we replaced the sofa in the room and everything turned to crap ! I wouldn't have believed it if I hadn't been there ! Of course, the couch never was returned to the listening room.