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What is the recommended spacing between houses? For instance 2 houses next to each other, for minimal sound interference and room to run wires, how much space is sufficient. I'm thinking something like 2' of concrete on either side of the house. Is this enough?

If the building isn't built yet, then this is an excellent opportunity to run exit hallways between theatres. That would cut down on the noise transmission. If that can't be done, then engineers can come up with sound reducing plans.

Try looking at this web page. http://www.troysoundwalls.com/theatre.html

A typical wall is drywall, studs, and drywall. A typical THX wall is 2 layers of drywall, studs, insulation, airspace, insulation, studs that don't touch the other studs, and 3 layers of drywall.

The reason for the different layers of drywall is that the two walls will vibrate at different or dissimilar frequencies and thus transmit less sound energy.

Sealing any airspace is your next priority. Then the surface of the theatre wall should be covered with acoustic cloth or panels.

My theatre doesn't have these properties and you can hear one room from the other. There is nothing I can do to the walls now that will quiet them.

Absolute physical separation of the rooms from each other is the goal.

The wall itself is responsible for reducing the transmission of sound from one room to the other. What you place on the wall determines what the sound will sound like in that particular room. So wall treatments on the surface of the wall will do very little to stop sound from traveling to other rooms, it just stops the sound echo in the room.

Note:

Concrete is more sound transmissive than wood, drywall and insulation. But 2' of concrete will stop just about anything, sound, bullets, automobiles.

SilverCity, Famous Players' 14-screen megaplex, has 8" re-inforced concrete. 2' is a whole hell of a lot of concrete that will just raise construction prices.

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"Would you like fries with that?"

Zamin

There are a lot of different ways to construct the demising walls between auditoriums. Iy is absolutely not necessary to provide exit hallways between each auditorium. The principles to be addressed are that the walls should be masde of a combination of different materials in order to effectively reduce sound transmission at different frequencies. In general, low frequency sound can only be stopped by mass, hence the concrete. To stop high frequency sound, a combination of batt insulation, sheetrock, and air space are required. Typically, a good sound wall will have a core of 12" solid concrete block with steel studs or furring channels on each side, not attached directly to the wall but supported on sound isolation clips. The studs will allow for an airspace between the concrete and the batt insulation. The opposite side can have the furring channels. Large is correct in stating that the number of layers of sheetrock on each side should be different to avoid sympathetic vibrations being set up in the assembly. All joints between sheetrock panels must be taped, and joints must be staggered between layers. Top and bottom of all walls must terminate at the structure (either floor or roof) and be acoustically caulked. A typical THX wall built this way will be approximately 22" thick. You must consult with a good acoustic engineer to get the best configuration for your particuular situation.

I often specify 1/16" sheet lead on the walls as it is very effective at stopping sub bass transmission

Gordon are you putting x-ray and CT scanners in the rooms with the sheet lead?

For its thickness Lead has the greatest density and is a standard in isolating recording studios from each other

Gord

I think it's crazy to use lead between theatres in a cinema, because we certainly don't have any clients who can afford it. I have designed x-ray labs (about 40 years ago) and all the walls were lead-lined. Today, with the newer, safer X-ray technology, I don't think they use lead even in x-ray labs. I agree that lead is the ideal material for low frequency sound attenuation, there are other simpler ways to deal with this issue.