Lotta questions in this post, but I'll try to hit some high points about stuff I know.
I want to make it a pretty hard core theater... well something in the upper echelon of low budget if that makes any sense.
First and foremost you need to decide on a budget, or how much you intend to invest annually and stick to it. A lot of HT's never get finished because to much money was spent to quick. Set a budget, divide the budget in to audio , video, and remodeling cost. And spend accordingly.
I need to know what kind of speaker wire to use. How to hide it. What if any, acoustic sound stuff on the walls should i use? Is there such thing as acoustic paint? Do i need to invest on the things i see online like Bass catcher and all that stuff?
speaker wire - monoprice.com 12 gauge 2 conductor
how to hide it - preferably fish it through the walls, or if you have carpet you can try stuffing it under the base board
acoustic paint? - none that I know of
acoustical treatment - it helps but is not necessary especially if you have a lower budget put that money into better gear and put off acoustical treatment until later
Keep in mind this is another trailer so the walls are not even sheet rock. Might upgrade to sheet rock later and can insulate at that point with acustic foam or something.. just not sure if its worth it or how much it cost.
If you take down the wall board and hang sheet rock it will make wiring a breeze but you won't get any acoustical improvements in the room just from having drywall. What the drywall and insulation is for is keeping the sound in your HT and not disturbing others in your home or near by neighbors.
Help with small details that people tend to overlook. Please help me and i welcome more design ideas but want to focus like i said, on things that people usually neglect that are cheap.
spend a lot of time in the forums, particularity "member system gallerias" and see what others have done. There is a wealth of knowledge here.
Also unlike the link were they hide the AV stuff, mine will likely sit on a AV rack or something under the TV.. any ideas?
What to do with the 1 window in the room?What could i do with the closet in the room?
Heavy drapes on the windows will block out the most light, The closet is an excellent place to put all the A/V gear. You just have to run the wires to it.
My biggest problem right now is if i decide to somehow have the AV stuff far away from the TV how to run such long HDMI and specially how to hang or place the center speaker..
Run the hdmi through the floor, under the room, up the inside of the wall, and into the back to the TV.
Put the center channel on a speaker stand under the TV.
Edit: speaker towers and such thing too.When i upgrade to 7.1 should i a) buy 2 more of the surround speakers or b) buy 2 more towers for side surround and move my current bookshelf surround speakers to rear surround?
If i were you I would hold off on the 7.1. You will not notice a big difference in the 7.1 over 5.1. Invest that money in remodeling.
Hope some of this was helpful. Best of luck and enjoying building your theater.
