speaker placement in a tough room, please help.

Thanks Rives,the room has a continuous slope from low to high. The room will be used as a dedicated room, I'm a little worried about how small it is, but these days in S.Cal the price of the room makes the equipment price seem almost inconsequential.

Dave: Then I stick with my first response. This is an area that none of the software programs address. You can model things in both areas, but you will likely not get very different results other than some minor modifications in the RT-60 response curve (Reverberation times for 60 db attenuation). Software programs do not address the psycho acoustical nature of what occurs. We're considering do some significant research and development in this area, but it's very expensive.

Rives, thanks for the response. Oddly enough when I had these speakers in a largish room ( 20x15) the sound was actually inferior than in my current smaller room (15x13).
This effect has been noticed by me on numerous systems, the intimacy of the perforamnce and the perceived transparency always seems to be lacking in the larger room.
This new room may be too small though and unfortunately I guess I'm going to have to learn to live with it; kids/wife and high-end being somewhat at ends.

Check out the excellent room setup guidelines at the Cardas
website:

http://www.cardas.com/insights/index.html

Also, try listening in the dark, so you don't focus on the
smaller room.

Dave: This is not an uncommon occurance. The reason has to do with the reverberation times of a large vs small room. In a small room the reverberation times are short and they actually add to the spaciousness of the image because psychoacoustically we hear these short reverberation times as part of the original signal. In a large room the reverberation times can be too long and they are perceived as a seperate signal disconnected from the original signal. The result is image smearing. One other thing that happens in a small room is pressurization of lower bass notes. You need about 28 feet to have a half wavelength of 20Hz. At whatever your maxium dimension is (diagonal is accepted) this will accomodate the maximum 1/2 wavelength. Any frequency lower than this will pressurize the room. You can get a bass gain from this (this is how car audio works in low frequencies). It is not as natural sounding, but if it occurs where the speakers naturally roll off it can create improved bass response. In general, large rooms can work better, but they have to be properly attenuated so that reverberation times at anything less than a 60dB drop are kept to a minimum. The biggest problem I see with your room is that 2 dimensions are very close to being the same and the ceiling height crosses through both of these dimensions as well. You are likely to have a boost around 50-55 Hz. Low frequencies like this are difficult to deal with using passive devices and usually require active equalization. If you feel the bass is not correct I would suggest you measure the room acoustically and see what the response is.