I'd get F. Alton Everest's "Sound Studio Construction on a Budget", which deals with acoustic treatment of domestic listening rooms (despite its title), and maybe the 4th edition of his "Master Handbook of Acoustics", for ideas on making your room into a decent listening venue. The close to equal L and W dimensions raise a problem, which you'll be able to see very clearly once you read about room nodes in either of his books. The electronic components and speakers are of course important too, but I'd start with the room, whose acoustic character (after treatment) will greatly affect your listening experience, IMHO. A room like yours will be a challenge, but it should be able to be met.
Is My Room Large Enough?
Need advice.My room is only 11'x13' and would like to make a dedicated listening area there.Want to use a tube amp and thought about smaller speakers such as B&W 805/804/803's perhaps.Trying to get a bit of distance from the walls for the speakers with decent chair position will be a problem and am willing to only use one chair. I listen to mostly jazz,classical and vocals not needing a lot of bass.I don't really listen to rock and I don't want to use a sub. I like the thought of a cozy room using a tube amp,as I have only used larger solid state amps in the past,but maybe this room is too tight for this.What do you think,can I make this work?