
You might want to have a look at this site... http://www.silcom.com/~aludwig/My_Music_Room.htm

Guess you missed the alcohol rehab program story with Dre... Yeah... some people just get rich and then destroy their image with stupid actions.

Get a book called Master Handbook of Acoustics by F. Alton Everest. It is the Bible of acoustics.
I'll give you some ideas but there are 1,000,000 people who know way more about this stuff than me and who will probably think I'm smoking glue again. (Got some?)
The first and most important thing is to understand that soundproofing consists of 2 totally different issues. First, sound-blocking and second, sound treatment. Sound blocking can be costly and consists of things like building a room inside a room. (floating room) Sound treatment is more about getting your room to represent the sound coming from your speakers as accurately as possible. I can really only give you ideas for sound treatment.
Make the 15 feet walls your length, front to back, and the 10 feet walls your width, side to side. Place your speakers on stands, not on a table or desk, and have them placed at least 3 feet from each side wall, 3 feet from the front wall, and 3 feet from each other. Place them so that the tweeters are at ear level pointing at your ears, or a little behind your ears, and so that they form an equilateral triangle with your head.
Have a friend come over and move a mirror placed flat along the walls and ceiling. Put a piece of painter's tape wherever you see your speakers in the mirror. This is where you will put your absorption and/or diffusion. Generally these spots will be on the front wall between the 2 speakers, on the side walls between the speakers and the listening position and on the ceiling between the listener and the speakers. As a general rule absorption is placed on the side walls and diffusion on the front and rear walls.
Study bass traps. www.ethanwiner.com/basstrap.html but don't go overboard on bass trapping in such a small room. Keep the wood floor but maybe scatter a couple strategically placed rugs.
One idea for the window would be to put a piece of plywood up, then some Basul Safe 'n' Sound insulation then some pegboard. This will do some sound blocking and might also act as a bass trap if located in a good place.
If you have to do extensive sound blocking you will be making your room substantially smaller because of the new set of walls you will probably want to add.
These are just some general, basic things that might help.
Joined: 2006-10-23