Room Acoustics Corner Problems

I have a room that is being constructed in my new house. This will be a dedicated listening room that is measuring 14 feet wide, 21 feet long, and 7.6 feet high. The back half of the room is a little wider at 16 feet. I have made as many soundwise decisions as possible based on my budget, however, I've just run into a problem. The plumbers have installed a large pipe for run off purposes in the front left hand corner of the room. In order to cover this ugly pipe they will need to either take a foot and a half off the front of the room (for example by putting a double studded wall up there) or they could taper the front corners (I would automatically taper the right corner as well just for aestetic purposes and to make it look even on both sides). By filling these corners with insulation and drywall etc essentially making it octagon shaped in the front of the room, will this cause any sonic disadvantage? Am I better off just making the room smaller and losing the extra 1.5 feet?


Why not take the opportunity to straddle both corners with bass traps. There are numerous recipes and ideas out there, but I think if you use some thick (3"-4") rigid fiberglass panels (2' wide) across each corner, and maybe some additional fiberglass to fill the space behind, you would have some nice bass traps. Cover the panels with burlap and you'll be all set.

Angles in the corners can be devised so as to redirect energy back to the listening position..You can also do this for all the ceiling wall junctions as well as the two remaining corners.Nothing wrong with a corner as long as it is not a 90 and plenty wrong with a bunch of fiberglass. If you latter find you need to tame a little high frequency splash then use long hair carded lambs wool.The natural wool is more linear in character and unlikely to suck the life away from the music as does foam or fiberglass.So has been my experience.Tom
There's a big difference between "taming a little high frequency splash" and building bass traps for the corners. Most of the experts and manufacturer's promote the use of fiberglass for room treatments. It is inexpensive and it works. It's quite possible (and even probable) that "long hair carded lambs wool" may work better then fiberglass for some areas, but I'm sure it costs much more.
I believe you can use the angle to your advantage--but how is not really so trivial. Bass traps for sure, but what type is the question and it depends on the rest of the room and speakers. The ones described above are predominantly absorptive and the least effective in most cases for low frequency due to the size of the wavelength you are trying to effect. Capacitive style trapping can work better, and you can build that in without the pipes being much of an issue.
Fiberglass works well in large areas that are very hot and that have long and multiple time lines. Taming such areas with fiberglass as well as diffusers can greatly enhance the intelligibility of the spoken word. However for most listening or theater rooms which are more regular in shape, angles at the areas I described maintain and redirect the pressure in the room without killing the dynamics.All to often absorptive materials or panels are used with good intent only to rob the resulting sound of natural air and life. So has been my experience.Tom
just to be clear, the room is essentially a mini L shaped and is unlike the trapagon cardas room (i wish). The bottom of the L is only 2 feet wider than the front half of the room. It essentially looks like this:
| |14 feet wide on this end
| |
| |___
| |
| |
|__________|16 feet wide on this end

I am using Quad 12L speakers (monitors) and a Cayin TA-30 Tube amp, NAD CDP

Does that change anyone's perspective?????

I have dedicated AC feeds to the front of the room (I am assuming that the best end for speakers is the 14 ft wide end with me seated on the wider axis (16 feet end). Hubbel outlets all around. RC channeling on all walls and ceiling with sound insullation in all walls as well (by the way, none of this is complete yet but will be soon). I do have the option of changing any of these plans but really have no idea what i am doing. Solid core door at the half way point of one side wall. I am not worried at this point about acoustic treatments. These can be added later correct? I want to make sure that the basic room construction ie studs, insulation, rc channeling, wiring, drywall techniques, corner options etc are all done to the best of my ability so that I am ready later. Also, the room is in a basement with concrete for front and back and one side wall. Obviously, I will be placeing studs and drywalls all around though. Does this help you guys in anyway? or change your opinions??????


from Mr. LOST
This sounds quite a bit like my finished basement listening room. The only difference I can tell is that mine is about 8' longer on the back of the L and the foot is another 5 feet wider. I'm surprised the pipe is going mean losing as much as 1.5 feet. I have a similar situation with the main sewage pipe that drops into my basement and then exits through the concrete wall to the septic tank. This required the wall to be located about 4" off that concrete wall. The stud wall that runs down the other concrete wall is held off 2" so as to prevent moisture wicking into the insulation from the concrete. I do wish I had hung a double thickness of drywall but it's not really a big deal.

I have come to find that we who have L shaped rooms have a somewhat different room in which to work as those with more rectangular setups. But that doesn't mean we can't achieve just as good results, it usually just takes more time experimenting with placement and acoustic treatments. For instance, I have found that my system fits the room and sounds best when set up completely in the toe and playing back towards the heel. Then to simulate the open side which is the top of the L I have added absorptive panels down the sole of the foot which is the right hand wall from the listening position. This and many bass traps are working very well but only after I got the speakers in the best location.

I'm sure Rives and others can give you better advice on how to construct the room. My comments are meant to suggest that you can still get great results with location and treatments once the room is finished so don't get to obsessed and make yourself crazy. Good luck and enjoy the process!
Randell try to create as much symmetry in the hard structure of the room. What happens on the left should be the same on the right so goes the front and the back. If you add an angle then I would add another, not just for aesthetics but for acoustic balance and predictability..If you need to adjust the sound after the fact you will find it easier to do so with more commonalty..If there are any overhead soffit areas then I would not make these with 90 degree angles, especially with your ceiling height.The pressure around these soffitts restrict the air flow within the room and creates dropouts. If you do indeed require soffits for plumbing or AC then I would put a 30 degree angle on their surfaces.Tom