Wooterb, first I should comment on Russ H. HT home theater architect. Just because he designed IMAX doesn't mean he is qualified for small room acoustics--they are very different. The fact is Russ H. is very qualified for small room acoustics, but my point is, don't take someone that has done studios and theaters as an expert in home theater or small listening room applications. Small rooms (less than 8000 cubic feet) for home listening and HT are very different animals--but the tools of the trade are the same. In fact we are redoing some rooms that were done by studio engineers--they were perfect for studios, the reverb times and everything are right on--but they sound terrible for home listening.
Now on to your real question: splayed walls. Two parallel walls will produce room modes. Some of these modes can have very high Q factors (they are narrow band and highly peaked). When you splay the walls you don't eliminate the mode, but you distribute it. The Q factor goes down as does the peak. The more the splay the lower the Q factor, until at some point there is basically very little left of a room mode. Splaying walls if very effective in this matter.
Why don't people splay walls? It's costly. It doesn't work that great for the resale value of your home. It is "unpredictable". The last statement is not at all true, but has been quoted from Alton Everest and others. He also doesn't believe splaying is very effective: calling it nominal--but I disagree here as well. (Everest's books by the way are still excellent--I just don't agree with everything in them) Splaying the walls is very predictable, but the math is much more complicated and not easily described. If you do intend to splay the walls, it's a good idea to work with an acoustical engineer and make sure it's right. I don't recommend most people to go the splayed wall route alone.
A comment on the golden triangle: Most of the previous work in our opinion is not quite right. It evenly weights axial, transaxial, and oblique modes. Oblique modes are almost negligible and axial should have 3 times the weighting factor of the transaxial. We are working on new ratios and new methods that better distribute actual real world results. We are not done with this work yet, and still take each room as a case by case basis.
As to Bill E. room: It will be fantastic. Bill is fortunate enough to be able to spend what is necessary to build this room (in an existing house no less- far more expensive than new construction). There are no parallel walls save one in the rear which is such a small surface area it is negligible. It is designed for 2 channel only, and the difference in design for 2 channel vs HT is pretty great. We are very anxious to get this room complete--and listen.
Please do visit our website at www.rivesaudio.com. It has been mentioned and the tutorial in the acoustical issues section should be helpful.
Now on to your real question: splayed walls. Two parallel walls will produce room modes. Some of these modes can have very high Q factors (they are narrow band and highly peaked). When you splay the walls you don't eliminate the mode, but you distribute it. The Q factor goes down as does the peak. The more the splay the lower the Q factor, until at some point there is basically very little left of a room mode. Splaying walls if very effective in this matter.
Why don't people splay walls? It's costly. It doesn't work that great for the resale value of your home. It is "unpredictable". The last statement is not at all true, but has been quoted from Alton Everest and others. He also doesn't believe splaying is very effective: calling it nominal--but I disagree here as well. (Everest's books by the way are still excellent--I just don't agree with everything in them) Splaying the walls is very predictable, but the math is much more complicated and not easily described. If you do intend to splay the walls, it's a good idea to work with an acoustical engineer and make sure it's right. I don't recommend most people to go the splayed wall route alone.
A comment on the golden triangle: Most of the previous work in our opinion is not quite right. It evenly weights axial, transaxial, and oblique modes. Oblique modes are almost negligible and axial should have 3 times the weighting factor of the transaxial. We are working on new ratios and new methods that better distribute actual real world results. We are not done with this work yet, and still take each room as a case by case basis.
As to Bill E. room: It will be fantastic. Bill is fortunate enough to be able to spend what is necessary to build this room (in an existing house no less- far more expensive than new construction). There are no parallel walls save one in the rear which is such a small surface area it is negligible. It is designed for 2 channel only, and the difference in design for 2 channel vs HT is pretty great. We are very anxious to get this room complete--and listen.
Please do visit our website at www.rivesaudio.com. It has been mentioned and the tutorial in the acoustical issues section should be helpful.