speaker placement in a tough room, please help.

Really could do with a bit of help here. My new room is going to be 10' wide by 11' long with a vault ceiling that starts at 8' and peaks at 15'.The vault is sloping up from the short wall. I'm guessing that I am putting my speakers (Hales sig 2's) on the short wall firing down the long wall. But do I put them firing down towards the high point of the vault or the opposite? Really prefer not to change speakers if possible.
Any suggestions/thoughts will be greatly appreciated.
I would recommend firing them from short to tall wall. The reason for this is 2 fold. One you will get a slight gain from going from a smaller area (volume), to a larger one. You effectively decreasing pressure through the room and will have the highest pressure behind the speakers. An added benefit to this is that by creating known pressure areas like this it is easy to acoustically treat them. The other reason I would fire to the high side, is that if you were firing to the low side you would get a reflection point off the ceiling behind you. It would be a long reflection time and would make the speakers less clear. You could treat the ceiling to get rid of the problem, but the easier solution is to just not work against nature and fire from short to long wall. Hope that helps.
I re-read your post and may have misunderstood the slope to your room. Is it centered about the room--so sloping in one direction from one side to the other? If it's a continuous sloping then I did read it correctly the first time, but if not my answer needs serious revision--please clarify.
I would point them firing toward the peak. This minimizes early reflections from the ceiling. I had a layout like this once and the image height was fantastic.
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


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.
Rives and Kana813, thanks for the responses. I always prefer to listen in a dark room regardless of size, since I agree with you that the distractions are absent and the music seems to bloom more.
Incidentally, the Hales Sig's 2 have little bass info below about 50Hz anyway. They utilize two 6" drivers for mids and lows. According to Paul Hales they were ample in the bass,however, most audiophiles including myself disagreed. IMHO only large drivers,i.e. 10"+ are able to really move any substanial air in order to reproduce the lowest frequencies. I know theoretically two 6" drivers equals one 12", but and this is a BIG but, I have never heard two 6's that could reproduce the bottom octave like one good 12".
I'll post on the results as soon as I have moved the speakers into the room and got them set up. Thanks again.
As to the driver question it's really the area of the driver that determines how much air can be moved. This alone does not determine the roll off frequency, but two 6 inch drivers can move as much air as one 10 inch driver. In addition a 6 inch driver has less momentum than a 10 inch driver and thus is easier to control. The result is typically two 6 inch drivers will deliver cleaner sounding bass notes than a single 10 inch driver.