Room acoustics - yet again

I have the books and the theory of room acoustics for rectengular enclosed rooms. Any guidelines for irregular (ie partly-cathedral ceilings, multiple openings to the listening room) ? Or is it the usual measure-listen-change ? My problem is finding a reasonable starting spot and tewak from there.
Oh boy... Can not spell ! Tweak it is.
Robert Harley and F. Alton Everest, names you doubtless know, dislike nonrectangular rooms because while they have resonant modes, these are much less predictable. I have a cathedral ceiling, and was advised by an acoustic treatment pro to take the rectangular part of it seriously, as if the sloped parts weren't there. That's all I can offer you, I'm afraid. Start from an analysis of the room as if the walls (or ceiling and floor) parallel to each other are the only surfaces you must deal with. How to continue? ??????
Specially with "real" world rooms (mine and yours I guess from your words) it's far more difficult to get decent sound, but at least you have the theoretical starting point. Be systematic on your approach and get a good test CD Stereophile or Chesky's.
For example in my case I have an opening instead of the left corner behind my listening position, so I know I have a bass leak and less than ideal response from there...
The further away from the rectangular closed the more you need to hone your accoustic tools in order to improve, so we're in the same boat....
Use the thirds approach get an SPL and test CD's and try to enjoy the trip. An Excel spreadsheet and plotting will also spell better the results than the plain numbers in a sheet of paper.
Hope you don't feel that alone in yuor quest
Another solution may be to listen in the nearfield, minimizing room effects. Granted, this won't help you in the low end that much, but from the midrange on-up you'll be fine and imaging/soundstaging will be near perfect. Even though I have a rectangular room dedicated to my system, it is too small too listen any other way w/ my speakers, which like to be at least 8 feet apart.
1. Try a modelling system like CARA that can accomodate irregular room shapes.
2. Try ETF which can measure what is actually going on.
Nice tip, could you please advise more details about CARA.
CARA is a german-developed software package that models rooms for the purpose of interpreting room acoustics. Their site is quite informative and includes an overview of how to use the software. It is at:

Rhintek, Inc. is the US representative for CARA. Our site is

Hope that helps!
Rainer McCown,
Rhintek, Inc.
This is a timely discussion as I'm about to move from a rectangular room to an irregular shaped one with a cathedral ceiling. The new space is easily twice the volume of the existing room. I also have a copy of CARA on order. My feeling is nothing will take the place of experimentation in determining the optimal system layout, but with the complex acoustic challenge of the new space some kind of help is necessary.

The reason I chose CARA was simple. While there are several products available that do rectangular rooms, CARA was the only one in my price range that does odd shapes. Once the dust settles I'll report back as to whether it was worth the $50.
I too am blessed (!) with a very irregularly-shaped room(s):
a two-foot sofa-enclosed jog-out on the left wall, and a 45- angled fireplaced cut-back on the right, with large openings right-front (to entry hall) and behind me into another smaller library-roon. Add to this a 7 ft Steinway B, and an insistent wife...phew! Yet I heartily disagree with the stated view above that irregularity is completely unfortunate!
Staggering driver/boundary distances becomes almost automatic, and problematic bass modes are smoothed, too! The piano's depth required that I find reference speakers that had sufficient bass to be way out from the front wall (8-9 ft), had great WAF, and worked in the nearfield (as a 7.5 ft triangle is all I had left). Several 3-ways (esp Nautilus) couldn't cohere in the nearfield, and rear-firing woofers (Verity Audio Fidelios) sounded anemic. Fortunately I was able to find outstanding speakers that work exceptionally-well (Parsifal Encores, woofers front-firing).
The triangle evolved by trial and error acoustically. I used
soundstage development and tonal cues as guides, as I was unaware of software for irregular shapes. The resultant soundstage is VERY deep, yet triangular (piano angles back starting 1 ft behind the speaker plane; opening on right rear). Having non-parallel
sidewalls seems to be very beneficial, as I have very little
first-reflection anomoli. Measurements indicate surprisingly flat bass response: only a mild bump at 80 Hz... although it's a little hot at 6kHz because I toed in to widen the sweet-spot and reduce reflections.
My friend who is pres/owner of a prestigious acoustical consulting firm (ex-BB&N Acentec) was pleasantly surprised at the stage I was able to produce. His "very good!" proclamation says a lot.
His sole mod was to lean forward even closer (only 6.5 ft off the plane); interestingly the guys at Verity Audio had suggested pulling my chair forward a bit as well. Sitting
in a 7 ft triangle in a 14x24 space seems a bit close, but
the soundstage is easily as wide as the room, and sometimes
20-30 feet deep (the Alephs help here)! Apologies for my quasi-bragadocio, but I want to urge you to proceed with confidence and good cheer, knowing that the asymmetry can have benefits.
Maybe you needn't worry too much about software-assistance, either, but I would urge you to be VERY careful with speaker selection. To risk repeating: whereas many 3-ways will cohere reasonably given
sufficient distance, I certainly found that extra care was required when selecting for near-field use. Getting the modernistic N803 past my wife was a great initial coup, but what awful sound in the nearfield! I had also been warned by some at this site that "loading" a piano soundboard in the room was a big taboo, and that non-parallel sidewalls
would result in a non-rectangular stage, but I certainly experience NO ringing or resonant overhang from the Steinway (maybe it helps that it's horizontal?--an upright would be problematic?), and I don't really miss hearing the "back corners" of the stage, as often referred to. Sorry to not be concise, but I'm now a firm believer that a well-damped, asymmetric living room can make a wonderful listening room as well. Visiting friends and musicians are soon transfixed, exclaiming often "it's like he/she's right THERE!..." Truly gratifying. So don't sweat the software and trust your ears when selecting speakers carefully. Hope this helped. Good luck. Ernie
O.K. I have an emergency here..... I just went by the new house I am having built. The room is 17'wide x 15' deep with cathedral ceilings. The carpet was laid yesterday and I thought that would tame things down a bit. BUT it got WORSE. Now if I stand in the the center of the room and clap my hands the slap echoe rings for at least another second!!! Although it rings in a nice little image in the center of the front wall, you can almost walk into it. Will the blinds, couch, and entertainment center cut down on this much? Should I allready have some treatments in hand when moving in? Having the ceiling lowered is not an option. HELP.....
Nomoney - yes, drapes, blinds and furniture will help enormously ! Before doing anything, wait until all furniture etc are in place. If you still have slap-echo, consider hanging stuff on the walls (I had a small oriental prayer rug one time). Actually, I found out that cathedral ceilings is actually a blessing - you don't have to worry about reflections from the ceiling too much. My problem is that my ceiling only goes half-way to the room, then drops down. This causes a placing problem for my speakers.

Thanks for the tips guys...
Thanks for sharing your experience, Subaruguru. My speakers are sealed cabinets and do well in a near-field setup. The software referenced above was only $50. For that much it won't have to do much to provide a decent ROI. Unlike you I have no WAF to consider, so can setup where ever sounds best (which is the current plan!).

Interestingly, after doing the usual over analysis of the situation my conclusion is similar to yours. While this new room is 'irregularly' shaped, that does not mean it isn't somewhat 'symmetrical'. My hunch is it's characteristics largely balance out. For example, the 'L'-shaped living room area is open on both ends. The kitchen is on one end, the hallway to the bedrooms on the other. There is also a small office area that adjoins the bedroom end of the space that has double doors that can be opened or closed depending on which works better.

In fact, 'space' was a key consideration in picking this place (it took 3 months of searching to find it). Now, for the first time, there will be adequate space between, behind AND beside the speakers. They'll actually have room to breathe. Can't wait! The only thing left is to actually do it. Everything else is just part of the challenge.
Ikarus, Thanks. I am hoping that is how it turns out. I might go ahead and try to have some things on hand to try and tame it down if needed. You know you can not go to sleep after moving into another house without the the stereo at least starting to sound right.
Yeah.. I know. I also know the feeling : 'leave the damn boxes where they are ! You can sort out pots and pans later ! Give me a hand with the speakers !' :)
I am going to build a large separate-from-my-house building just for two channel audio. I am thinking 40'x40' or larger.

Does anybody know of any plans that include recommended material for the floor, walls, ceiling and wall angles, etc?

I would like to take this plan to an architect so that he can draw up something that will 1) pass building code and 2) allow a general contractor to begin building.

If there are no known plans, does anybody have an architect that they recommend? I am in Raleigh, NC.

Sol322 wrote: "Nice tip, could you please advise more details about CARA."

I wrote a full description/review in the September Stereophile.
thanks for the update I already have checked the mag!!!