I have no idea! But, somehow, I can't forget it.
I was visiting a London TV-news company, installing or maintaining some software in their accounting department. When the work was finished, my contact took me on a quick tour of the studios. There was one in which some guys were working on setting up some props or furniture or something, and they had some light music playing on a casually-placed single speaker. Was it the room treatment, the speaker or both? I don't know, but I was so struck by the clarity and quality of this sound that I still recall the impression it made, twenty years later!