I have a room that is 10x22, that, while not a perfect rectangle, is pretty close. I have acoustic drop ceiling tiles (already there when I moved in--5/8" thick made of fibreglass--the yellow stuff like the Owens 703, just thinner). The "rear" of the room (behind the listener) is curtained off (I have to use 10x7 of the room for storage and I did not want to build a wall). The storage area is quite full of various boxes, shelves and whatnot, so bass traps in there are impractical at this time (perhaps in a year or two). This leaves me with a 10x15 space with which to work. I've plotted my FR with the BFD spreadsheet and RS SPL analogue meter. (I have no idea how to post an image but the response is flat from 25 to 40, rises gently by 5 dB from 20 to 25, drops by 13.5 dB from 40 to 50, rises by 3.5 dB from 50 to 56, dips by 9 dB from 56 to 63, rises by an equal amount to 71, is flat to 89, rises gently by 6 dB to 111, dips by 7 dB to 125 and rises back to flat (+/- 1.5 dB) to 160 (relative to the 71 to 89 stretch). 2076.5 22 80.5 2584.0 2884.5 31.584.5 3685.0 4085.5 4580.5 5071.5 5675.0 6366.0 7175.0 8076.5 8975.5 10079.5 11181.0 12572.5 142.575.5 16074.5 The first column is the frequencies, the second the (corrected) dBs. This was plotted from the listening position using the sub and the mains, crossed at 80hz (I tried 60, 100, 120 and 150, but 80 was the flattest). After many hours of plotting and moving the sub, this was as flat as I could get the curve. I cannot place standard corner traps up front (behind the sub and mains) because of space constraints. I had thought to make my own "half" corner trap for the corner farthest from the sub (my right, from the listening position) by getting a box of the acoustic ceiling panels and stacking them/cutting them to fit. I can place a trap in that corner about 3 feet high and 4 inches thick. The other corner is not usable as it holds some of my gear (no way around that for awhile). I thought to make my own version of the ASC Subtrap by placing a stack of 2x2 of the ceiling tiles, about 18" thick, sandwiched between two pieces of MDF (say 1/2 or 3/4 of an inch thick) wrapped in cloth. Would that act as a bass trap well enough to partially compensate for the lack of a corner one, or is it just a waste of time? Sorry about the length of my post, but without pictures, I needed to describe it as best as I can.