It's a little nice being in the'do it yourself kind of business' like soundproofing. In today's world taking the family out on a Fri. night for dinner and a movie might cost more than your monthly mortgage payment. That is why many families are opting for their own home Theater. If you have got a spare room or an empty space in your basement or attic, you've a potential Home Theater.
It used to be that the only way to build a home theater or a home studio was to construct new wall within the existing room and then build what we call a'Room inside a room.' Though this technique of soundproofing is still reasonably effective, it is expensive and eats up a lot of wall space in your already cramped theater room.
A better recommendation is to work with your existing window exhaust fan walls by using a new layer of Windows Exhaust Fan drywall to the present walls and ceiling but using a layer of a product called Green Glue on the new drywall and sandwich it between the existing wall and the new drywall. If you do this to all of the walls and the ceiling you are well on your way to a great soundproof home theater. If you are planning on having carpet and pad for the finished floor in your theater, then a soundproof floor underlay would be in order. These are both recycled rubber products that would lie on top of of the wood or concrete sub floor to stop the airborne sounds of the home theater from traveling down to the people below.

The Impactless is a less dense rubber underlay and would be good for under carpet and Attic Ventilation Fans pad. The North American Impact Standard would also be effective under the carpet and pad, but is more suited for hardwood and ceramic tile floors due to its sheer mass.

Other concerns that you might have with your house theater would be doors and windows. Most modern bedroom doors are hollow core and do tiny in the way of soundproofing. Your best bet would be to go to Home Depot or Lowe's and get a solid core MDF or solid wood door. You might ad an automatic drop down transom seal to the base of the door and also a door perimeter seal kit to seals round the door where it closes into the jam. A genuine soundproof door could cost thousands, with a little time and well thought out planning ; you can get similar results at 1/4 the price tag.
the last thing we want to talk about are the windows in your house theater. If neighbours are a concern, then I would suggest building window plugs with the 2' America Mat closed cell vinyl nitrile froth mat. For instance, if your window
Wall Exhaust Fan were 3' X 3', you would cut the foam to 3'1' X 3' 1' therefore giving the window plug and additional 1/2' around it's whole fringe. This extra 1/2' will help to hold the window plug tightly into the window frame very similar to a cork in a bottle. These wood panels can be discovered at home Depot or Lowe's.

Out!!!

Build your home theater