My Room Layout
This is a very rough diagrammatic of my room layout. The boxes on the right wall are my subwoofer and an Ikea pine table, underwhich is a small A/V trolley with my Quad 77 amp. The surround speakers are not depicted. There are windows on the front and rear walls (covered with curtains). Also, the speakers are toed-in, but I can only draw simple shapes. The display cabinet has glass doors on the top half.
Because of the window and doorway at the rear wall, most of the sound can flow through to the adjoining room. This means that for bass purposes, my room is more like 12' x 26' rather than 12' x 13'.
My listening position is nearly an equilateral triangle. Also, I started out with my speakers 5' apart and I finally moved them all the way out to 6' apart.
I don't seem to have any bass problems, perhaps because the Zephyrs are slightly bass light, but perhaps because on the left hand side is a cabinet stuffed with loads of stuff, especially books, which make for good bass absorbers. My little sofa probably helps out too. This also applies to the adjoining room. Note: After trying different positions, I realised that listening closing than 6' causes the bass to become too much/relentless for my liking. Quite interesting considering that going nearer to the speakers is not really supposed to increase the bass.
Room treatment is basically Sonex 1" panels on the front wall, 2" panels cut to size everywhere else. There's still room for more treatement, especially the ceiling, which is just a large plywood board. There's a Malaysian company making tube-trap lookalikes for a fraction of the price; I'll be looking into that too.
The above discussion is actually a simplified discussion and the picture above is not 100% accurate as I only know how to draw simple shapes :).
So given a rear wall that is not perfectly perpendicular to the side walls and the general assymmetry, placing the speakers in the normal fashion (i.e. as if the room was symmetrical and a pefect rectangle) would clearly result in a slight loss of imaging accuracy. Therefore, I tried to rotate the axis of the speakers and ensuring that the distance from each speaker to the listener is the same, to get a position where the image is placed dead centre. I'm still trying different positions, so the above diagram shows the concept rather than any 'final' position.
My rear wall has a window (its an extended balcony), and I've placed a 2" thick sonex panel there. A/B comparisons clearly show an improvement as the hashy reflections from the windows are absorbed. The rear wall also has 1/2 length black-out curtains. I find that if I use the curtains (with the Sonex), too much of the ambience is absorbed and there is a general lack of 'air'. The difference the curtains make is very significant but I often overlook it. Sometimes the sound seems 'wrong' and then I realise that the curtains are shut :)
ATT Guru Calvin Choe Comments about the abovementioned room layout [which isn't my current layout as it doesn't include the ATT 1.0 in the front corners - its hard to update everything on my website :)]
Definitely something for me to think about though I think that the sound I'm getting is definitely not overdamped. Its a small tiny room with quite a bit of glass (glass cabinet on the left, windows at front and rear) and the Zephyrs have a 'fast and forward' type of sound.