Ask him about non-parallel walls too, my friend recently added a new room to his house, for his HT mostly (and a second full bathroom, he has teenage daughters), and it really sounds great. A mutual friend of ours bought an older house with a "music room" where the only flat thing in it was the floor, nothing else is, it's all curved or angled. It had a huge piano in it that came with the house, it was sold and the cash bought some nice new equipment. That room has the best acoustics of any house I have ever been in. Even cheap stuff sounds pretty good in there, and good stuff sounds tremendous.
The contractor thought he was nuts for wanting to do it, but even he admits it sounds great after it was all done. It has deadening panels on the front walls, and partially back on the sides and ceiling, and the floor has really heavy carpet. We were watching some TV show and there was a restaurant scene and we could understand everything the people at the surrounding tables were saying. A couple of them were talking about how they got jobs as extras on the show. I had recorded the same program at home and couldn't understand more than a few words, it was all a jumble. Everything seems to sound really clean in that room, it's hard to describe what it does exactly, but the angled walls and curved ceiling only added a little over a thousand bucks to the total, and it was well worth it. It was too bright at first, so the panels were added after a quick test before they painted anything and so it cost only a few hunded dollars to add them ourselves. A roller and some sort of nice smelling glue he bought locally, and we got them up in a couple of hours.
Piano isn't my thing, but it's scary realistic in that room, if it's a good recording. If I ever build a house, or do a major remodel, I'm going to do it for sure.
