But if I won the lottery (and I mean mega-millions not a lil' 6 figure payout), I'd dig up my backyard to start, probably 8 feet deep. The neighbors all think I'm getting a pool but things are about to get weird. You see, I'm insane so I'm putting over 2/3 of my listening room underground to minimize sound leakeage and the need for climate control. I'm not a mole person, so there will be another 5 feet above ground with windows to let in light. Just low enough that the neighbors can't complain about seeing it from their yard.
As a few of you have mentioned already, non-parallel walls, I want to put myself nearer the narrow end of the room with a slatted desk to minimize reflections, but still give me a usable work surface. I haven't put this down on paper, so let's just ballpark and say the narrow end is 10 feet wide and the wide end is 15 feet wide, and the length of the room is 20 feet - ballpark, my backyard is trashed at this point so I'm going to do the math and figure out what the room modes are in each dimension WxDxH and try to get them away from my head - which is why this room is so tall by the by, keeps my seated head height of 4 feet off the 1/3 or 1/2 mark between floor and ceiling. Oh and to make things more difficult for the architect we're going to go ahead and slope the ceiling too, starting from the full 13 feet at front and coming down to 9 feet at the back. I want that extra foot because as you'll see in a moment we're going to lose a lot of volume to acoustic treatment. Also I'm tall and I don't want to feel claustrophobic in here.
BUT WAIT THERE'S MORE. Now we get to furnish this wonderful acoustic hellscape. You see, acoustics is easy (and by easy I mean "solvable by those without a doctorate in acoustics") if you follow one of two rules:
1. Have a space large enough to cancel out most of the smaller reflections and just worry about the overall shape and proportions of the space (which is fine for stadiums and such, but doesn't help us now) OR
2. Use a square/rectangular room - you can more or less calculate the room modes in each dimension and estimate where they're going to be, and then tune your acoustic treatment accordingly. But I just built a room out of triangles so that idea has gone out the elevated ground-level custom windows (which are awesome and totally worth it by the way).
No matter, we're going to be throwing a solid 5 figures of acoustic treatment at this problem, 8 inch panels mounted as far again off the walls and ceiling, slightly angled towards the listening position just to make things harder for the god-forsaken construction crew stupid enough to work for the architect who was desperate enough to work for me. The panels on the walls run floor to ceiling in 4 separate 4 foot stripes with equal gaps between them front to rear. And of course we take a hole saw to these frames to maximize the absorbing surface area even on the sides of the panels - plus corner treatment where the walls and ceiling meet and my windows stop. Similar treatment for the ceiling though let's just do 3 4 foot stripes hanging level, and we're going to mount mirrors on the sides of these panels at an angle so they can reflect the outside light from my windows down into my workspace. The front wall is fully treated up to the windows, by the time you have enough acoustic mass that close to the speakers to absorb full range sound, it takes up a lot of space. I'm assuming that wall is just gone and my speakers and computer monitor all have to be freestanding, and I have to make cables look neat and tidy outside of the walls. The back wall is more interesting, as this is where we have not one, not two, but three doors. One on each side of the rear for a machine room on one side, storage on the other, and the actual entrance in the rear center from an outside stairwell leading to ground level. Treatment for the backwall is going to be tuned membrane traps at the same height as the speakers, tuned to the resonance that goes with the length of the room, and the first harmonic above that. I'd also have some furniture back here, maybe my keyboards if I have any left after the inevitable divorce this whole project has caused. That should diffuse and soften reflections from the rear wall nicely, though realistically (as if anything about this scenario was realistic) there's going to be some trial and error to get such a weird room in good listening shape.
Same reason a totally square room is terrible sonically.
