While my current plan is still the expanding foam, I have a question for you. Would it be sufficient to use conventional bracing methods to make the reflector panels (or folds or whatever you want to call them) completely rigid, and then leave the backs of the speakers completely open? See, as it stands, my speakers have no top, bottom or back. As I see it, if you didn't enclose the rear of the thing, the chambers wouldn't act as resonators because the standing waves would simply dissipate into the room.

So with plenty of bracing on the reflector panels and simply leaving the back of the speaker exposed, could you sucessfully solve both problems? At the cost of looks of course... Just curious.

Adam