I was hoping to put off room measurement for a little while. I though perhaps the effective range of an HR might be wide enough to encompass a room mode, but I suppose not. What would you do with this riser in the interim?
If I seal it, screw down the top, and drill holes, I end up with an HR. If I seal it but don't screw the top, I have a membrane absorber (right?). If I open the entire front to expose the fiberglass, I have a broadband absorber, though with an area of only 8 sq ft.
What if I screw down the top and do nothing else? Would that sealed (and fiberglass-filled) box have a negative impact on the room?
As well, for a carpeted room, what percentage of the room's wall area should be covered with broadband absorption traps?
I have nine 2'x'4'x4" traps on my walls. Total wall and ceiling area, not including floors, is around 425 sq ft. My traps cover 56 sq ft, or about 13%. The room still sounds like it's resonating, but I need a number to shoot for before I buy material for more traps so I don't end up dampening the life out of it. The plan right now is to buy 12 more 2x4'x2" sheets and cover most of the ceiling with them.
Thanks again for you help.