Ideal Listening room

I have the opportunity to finish a second floor level walk-in attic space over my garage from scratch. The space when finished will be 11 feet wide if I use a 5 foot knee wall, or 13 feet wide for a 4 foot knee wall. The room length is 18 feet. The ceiling height will be 7ft 6 in if I panel the existing collar ties to create a flat ceiling in the center of the room. The center flat section is about 6 feet wide. I have no clue as to the acoustics of such a space. Another option is to paint the collar ties and panel the cathedral ceiling above which reaches a height of 9 ft 8 inches at the apex. I obviously need professional help. I am concerned about the size of the room and issues with low end nodes. I may use Reeves for assistance regarding building materials and room treatments but is there another consulting group so that I will have two opinions??

Any comments about the overall acoustics of sloping attic walls?

Would you place the speakers facing the long or short dimension?

Is the narrow width of this room and low ceiling a problem?

If I put the speakers facing the long dimension, then at 7 feet apart, they will only be off the vertical knee side walls by around 1-2 feet. Is this enough?
Will low end resonance be a big issue?
Your space could become an excellent listening room.

For professional help, I'd contact Rives Audio ( He has several layers of service available and from reputation you'll get the most bang for you buck this way, unless your willing to take a crash course in acoustic design. If you want try this on your own, you might consult the Jeff Hedback @ they will provide materials and advice too.

The slopping walls could be an advantage-less parallel surfaces. I wouldn't worry about them.

Since this is part of your house, and you might not want to disturb others ask Rives about constucting isolated walls with resilient channel. You can play your system long into the night and not disturb anyone. Rooms constructed this way tend to sound excellent too. Go to the Acoustic Sience Corporation website and look at their Iso-Wall system.

My friend has a room with similar dimensions and his system sounds great with speakers on the short wall. He gets an incredibly wide soundstage listening nearfield. However Rives can really help with this too and probably guide you on speaker selection somewhat if you haven't made a purchase.

The low ceiling and narrow sidewalls can be easily fixed by using diffusion products. These products have the ability to make your room sound cathedral like.

Rives will also be able to compensate for any resonance issues with bass absorption.

From my experience, you haven't heard your system until you have a well built listening room. In fact, I would consider this the ultimate "front end" and spend whatever needed to get this right. Only then will you truly hear what your components are capable of.

Good listening,
Suggestion: put built in cabinets in one of the knee walls for your equipment. I have a room of similiar shape, but a little larger, which I turned into a home theater. I second the recommendation to contact Rives audio. I consulted with them on my room and it was worth every penny. Send me your email and I'll send you some digipics.

Good luck,
Did you put your speaks on the long or short wall? My attic space will be finished at 11 feet by 18 feet. If I build equipment racks into the knee walls then the speakers will be facing the shorter room dimension. I am not sure this will work with such a narrow room?