Im completely new to all the room building stuff but ive been reading on the forums here and looking at some pictures. The room im wanting to build is more of a regular type room, no theater style seating or things like that.
Right now I have all of my stuff (50" plasma, speakers, computer) in the master bedroom, currently the biggest room in the house but im hoping to change that soon. Ive done the best I can with a tape measure and sketching it out on floorplaner.com to give you the best visual of what things look like. http://floorplanner.com/projects/18680505-my-first-project

Now that I have a visual of how the room will look like, one of my first ideas was to have even dimensions for the room, 17' front and back and 12' for the sides. Ive read that square rooms can be bad for music and I dont want that since this room will be used a lot for music listening and watching movies. The ceiling height in the basement area where the new room will be is 7' 2" and theres some ductwork near the playroom wall that hangs down 9.75" so that poses a problem there I think, kinda low ceiling height in one spot along the back of the new room. I was wanting a suspended ceiling, just those lightweight square tile things that push up easily so its less costly and easier to get to wires and stuff overhead if need be but im not sure how it will sound for music with the current ceiling height vs drywall or whatever is normally used for ceilings.

My second idea as you can see in the room picture, is putting up the new right wall of 12' and taking the paneling wall of 20' down and merge the playroom with the new room, that way no square room. With this method, I will put my 50" screen at the new back 17' wall and speakers on left and right.
If I mount my TV to the wall I could put my pro audio gear rack in the middle or I could put it out to either side of the room, or as ive seen other people do, have a little closet like area on the right wall with the equipment in there. Id actually prefer this way because I have two pro audio amps with noisey fans that would need to be modified if they arent closed up like they are now.

So basically im looking for any input about the existing room and the new future room, and how my gear can be placed within. Im just going to mount the 50" tv on the new back 17' basement wall with speakers on left and right and maybe add a small closet on the right wall for the amps, and put my computer desk on the left wall near the window, and two chairs in the middle of the room unless someone can give me some better advice on how to setup this new room. Thanks for any help!

your idea of a new wall is very good. It gives you a clean wall to mount your TV or screen on and if you make an equipment rack built in, it becomes a false wall giving you access to the back side of the wall and the rear of all your equipment. I hate trying to get to cables and connections on the back of a/v equipment when it is stacked in a closed rack or pushed up against a wall. Wiring the front 3 speakers and the subwoofer is easy. Wiring for the surrounds can run in along the top of the side walls behind some simple moulding, then into the wall cavity and down the wall to the speaker mounting locations.

your idea of a new wall is very good. It gives you a clean wall to mount your TV or screen on and if you make an equipment rack built in, it becomes a false wall giving you access to the back side of the wall and the rear of all your equipment.

Thanks, I cant wait to have the tv mounted on the wall, itle look so much better and have more space underneath for things. Ive actualy decided to use the space for a closet thats between the HVAC and the back wall where the tv will be mounted. I can put my amps in there and other stuff if need be. Also with the closet being there its the closest to where the speakers will be so it will have the shortest wire run to the speakers as possible.

Another thing I forgot to mention is soundproofing. I will need to soundproof or do something to reduce the amount of bass that gets through the basement walls and to outside as much as possible on a budget. I like to listen to movies and music loud with the pro audio gear and theres a house right next door thats only about 20ft away or so.

So my question is will the soundproofing change the way that the sounds will be heard in the room at all or will it actually help? Thats my main concern with soundproofing. Also whats a good way to go about soundproofing a new room? What type of materials should be used?

Edit: After reading up on a few topics on here and websites,(I shouldve done that first, duh!) I came across the 4 elements of room construction. It seems like it should help a lot with the low freq passing through the walls. It also doesnt increase the cost by a significant amount which I was afraid of even though using the staggered studs, 2 sheets of 5/8" drywall and green glue increase the cost, it should be worth it if I can listen to music and movies at loud levels without worrying about a knock at the door!

Keep in mind that all that DD+GG is all for naught if you go with a drop ceiling. The sound will just escape through the non-drywall ceiling. If you don't plan on DD+GG for the ceiling then don't bother with the rest of the room. Save your $$ since the drop ceiling will be your weakest link.