Rick, that is great, I'm trying to decide what to do...the tri-traps are more expensive, but seem to have much better absorption compared to traps that span corners. Everything is better than foam, based on my recent studies. If the trap is made from rigid fiberglass like owens corning 703, or using mineral wool board (cheaper) your good to go. The 440 and 442 (1st/2nd reflections) are much much cheaper.
I've learned tons from the Realtraps website. The videos showing how nulls can exist within 1" is amazing. Ethan's HT room is killer with 39 traps. I've also learned that what people say about HT being differant than music for treatments is not true, the main goal is to achieve a flat as possible frequency curve. Reducing ringing, combing is also very important. You can't do that with just furniture, drapes, etc...
I'm also tossing around the idea of building my own. It might be cheaper than building them. Insulationworld.com has good prices on Owens Corning Mineral Wool board.
