http://www.trapagon.com/Audio/Products/body_products.html

http://www.crystalaudiovideo.com/cmptechnology.asp

http://www.gspr.com/canton/ref2.html

http://www.humanspeakers.com/diy/cabinets.htm

And many more. The conventional wisom seems to be that parallel walls encourage standing waves. I haven't tried to analyze if this should be true or not. The conventional wisdom is probably based on empirical experience of different builders.

What do you think? I am trempted to build my future BR cabinets with trapezoidal shapes.
thanks
-akhilesh