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Im about to start working with my contractor on building my home theater (8 seats)
I would like to know the steps for sound proofing the room

thanks
 

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Is the room already framed? If not, there are a lot of things that can be done reasonably to help quite a bit.

Just remember that sound travels through the air and through the structure.

Decouple the room from the rest of the house as much as possible.

Seal ALL holes (outlets, switches, lights, etc.) or better yet, do them so they don't make holes in the sealed room

Use a solid core wood door with seals

Pay a lot of attention to how you're going to heat and cool the room as HVAC systems snake all through a house and transmit sound both ways very easily.

Bryan
 

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Another note on the AC. Do NOT use the metal ductwork, you want to use the ductboard and make sure you have some Z turns in it to reduce sound transmission.

There are a lot of ideas on the board and most are not incorrect, just not the prefered methods. Many people cool the room and then have an air return above their projector where others vent at the projector and pull from another part of the room. Both will work; however, one can cause condensation on the projector.

Best advice is read, read and read and when you think you know, post your thoughts to see what advice you can get.

That is what I have been and are currently doing.
 

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Agreed on the non-metal. Just also understand that ductboard won't provide isolation. The board needs to be inside a box structure with mating bends to provide the mass to stop bass passing directly through the ductboard.

In that type of construction, you can also use flex duct inside MDF boxing to provide the same effect.

Bryan
 

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Agreed.

I planned on running my ductwork inside my sealed room in the soffit area. This ensures plenty of isolation while the ductboard prevents the high freqs from running through the house.
 

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One Layer 1/2" drywall over 5/8" layer of drywall with Green Glue or Quiet Glue between the layers. Simple, effective. Not cheap, but less expensive than some methods that are not as effective. Staggered stud or double wall framing with the double drywall method.
 

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I realize this is an old thread, however, people pour through old threads like this for insight. In general:

Decouple the new drywall surfaces from the original framing via a decoupling means.

Add Absorption, generally R13 or R19 fiberglass insulation.

Add mass. This is a bargain using standard $8 drywall. Use double 5/8"

Add damping. Different materials used for this.

These are the 4 elements in play with soundproofing. This article may help clarify: http://www.soundproofingcompany.com/library/articles/elements_of_room_construction/
 

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Hey Ted,

Can you please explain to me why we want to build our soffit system after the room is framed and drywalled? If you're building a room within a room, why wouldn't you frame your soffit when your framing your room, then add your layers of drywall around the soffit system? Otherwise you'll have to drill through, cut holes through and attempt to securely mount the soffit over existing drywall.

I read in one thread that you and another fella (who was also in the sound isolation business) were instructing another poster to mount the soffit outside the drywall. But I never did hear the reasoning behind it.

I understand that this is the preferred method, I'd just like to understand why this is preferred over framing the room with the soffit.

Thanks for your time.
 

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Reasonable question. First, you and anyone else can send me a PM with an email address and I'll send you a couple of heavily illustrated articles on the topic.

If the soffit is framing over a beam or ductwork then you would frame the soffit before drywalling as you said.

If the soffit will have lighting and you don't want sound leaking out (or in) then you will need the ceiling and wall drywall completed. Just one layer of drywall would suffice.

If the soffit is to house ductwork and act as a muffler then the soffit must be sealed on all four sides
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There should be no need to 'cut holes and drill through' if you plan ahead. If you know where your soffiting will be, make sure there's a good place to attach to along that path prior to drywalling the ceiling.

After that, the only holes are those going through the framing, through the drywall, and into the mounting points. That's already pretty well sealed up.

Bryan
 

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thanks Ted for those very informative pdf's. I now understand why we want to have a separate soffit system. Your handouts spoke about a dead vent. I take it that's the cold air return system? Can you speak some more about the dead vent system, it's purpose, different types of construction methods, etc....

Uncle
 

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Hey Bryan,

Do you know the load carrying capacity of the res bar? I curious about the lbs/sqft a proper soffit system would weigh.

By proper soffit system I mean a partitioned soffit with venting on one side, sealed off from the electrical side with either OSB, or MDF. Then you would have your 2 layers of DW with GG on the exterior.

Is there more heavy duty options to res bar?
 

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Uncle,

Glad the articles helped. Soffits are generally quite long which gives us all that length to attenuate sound. Every foot of travel through the soffit reduces the sound more and more. Soffits are long and thin.

The Dead Vent is short and squat. Used if soffits aren't available / convenient. Both soffits and Dead Vent can be used to exchange air with the rest of the basement OR to interface with the main HVAC system.

Side note: I wouldn't spec resilient channel ever. The fact is there is no single standard for its construction. Some is 20 gauge, some 25, some in between. Some are slotted for flex, some are solid, some have holes.

Again, there isn't a standard for strength or flexability. Drywall Furring Channel, on the other hand, is specified by the Steel Stud Manufacturers Association, along with all other steel framing components.

This method of decoupling is effective if the steel can act like a spring. Since there's no manufacturing standard, the net result is that you have no idea if the resilient channel is too stiff (no spring) or too loose (no spring).

Much better to use the commodity resilient sound clips for a buck and a half and Drywall Furring Channel for $3 for a 12 foot stick. For a little over $40 you can install a ceiling with these steel clips + channel that would put any resilient channel ceiling to shame.
 

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Hey Bryan,

Do you know the load carrying capacity of the res bar? I curious about the lbs/sqft a proper soffit system would weigh.

By proper soffit system I mean a partitioned soffit with venting on one side, sealed off from the electrical side with either OSB, or MDF. Then you would have your 2 layers of DW with GG on the exterior.

Is there more heavy duty options to res bar?
Sry - not sure what you're asking here.

If you do a set of RSIC-1/Whisper clips at the ceiling edge of the soffit, it's not an issue overall.

Bryan
 

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Part of the real issue is that res bar has no spec and no ratings. The Drywall Furring Channel that is used with clips, on the oher hand, is rated by the SSMA.
 

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So I've only seen pictures of this product on line. Are the clips used in conjunction with the furring channel? or are the clips just 2" pieces of the furring channel used for spot contact?

Ya, I used res bar in my last theater, meh. However I do like the look of this DW furring channel. It looks much better than the res bar I used. I never knew DW furring channel and clips existed.
 

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Clips are installed in an array. Then the Drywall Furring Channel is inserted into the clips
 

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Spring is the operative word. A spring will bring great isolation benefits. Resillient channel can sag, and just hang there. No spring. Or be short circuited, and become rigid. No spring.

The clip + channel system really can't be compromised, unless you really, really tried.
 
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