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How to maintain sound isolation when equipment rack is not in theater??

post #1 of 16
Thread Starter 
So I need to run a bunch of cable from my equipment rack to the theater... I am estimating about a 1.5" conduit. I am thinking of using smurf pipe, but here are the issues:

1) I need to cut a 1.5" hole in the header
2) The smurf pipe will basically exit into the room (no terminators)

So how does one deal with a 1.5" pipe which is a wide open "straw" into the attic? Doesn't this put a big damper on the whole isolation thing??

Any suggestions?

Thanks!
post #2 of 16
I think the goal is to create an airtight seal around the conduit so sound can't escape that way, and make sure the conduit doesn't end somewhere you can't tolerate some noise leakage. You will also want to stuff the conduit with something to try to make it airtight on both ends as well.
post #3 of 16
foam it shut?
post #4 of 16
If the conduit runs from the equipment room, through the attic, and into the theater - then it isn't open to the attic, just on both ends. So maybe just cover the conduit running through the attic with a fiberglass blanket if sound escaping through the conduit walls into the attic is a concern. Or were you concerned with sound leaking out the end of the conduit into the equipment room?
post #5 of 16
Thread Starter 
I can go either way -

I can run conduit just up the theater wall into attic and leave it open, which will cause sound to leak into the attic

Or I can run full conduit up theater wall, across attic, and into cabinet. But my cabinet is actually in the closet of a bedroom, so I am concerned that I am providing a nice easy path for sound to travel through.
post #6 of 16
Here's the best you can do (why am I telling people this? geeze, it takes money out of my pocket. Hey buddy, you got a buck for a cup of coffee?)

Where the conduit enters the room (through the drywall), maker certain the conduit does not touch the drywall. You can use a flexible caulk (Ted has some acoustic caulk that will work well) to seal the gap between the conduit and drywall.

Where the conduit passes through framing, cut the hole bigger than the conduit and do exactly the same thing ... don't let it touch the framing...use caulk to seal the gap.

Where the conduit runs through a wall, make certain it cannot contact either side of the walls (back side of the drywall) or any framing ... you don't want rattles. Where you use clamps or attaching brackets to secure the conduit inside the walls, get slightly oversized and use pipe wrap between the bracket and the conduit.

If you want to go "over the top", wrap the entire conduit run.

At each end, once your wires are pulled, plug the ends with fiberglass but make sure you can pull that fiberglass out in case you run a new wire in the future.
post #7 of 16
Doesn't he have to use fire caulking if he's cutting a hole in the header? Is the acoustic caulk fire-rated?
post #8 of 16
The sealants I've found that have the same flex properties are fire rated.....gtee 10+ years they stay soft and flexible....that's why they're good for these applications
post #9 of 16
Okay. I'm going to go out on a limb here. Those of you that follow my thread know that I have been very anal about my sound isolation, however, in the OP's case....I would just stuff some fiberglass in the conduit. What we are really talking about here is about 3 square inches of space out of many, many square feet of wall space. So some of the sounds leaks? Really? Into the attic? So what. Now, the only arguement from a physics standpoint I can see is that if this guy really has an air tight room, then that 3 square inches does ruin it. Howoever, I would venture to say that very, very few of us really have an air tight room.

I still can't believe what side of the fence I am find myself coming down on.
post #10 of 16
Quote:
Originally Posted by Elill View Post

The sealants I've found that have the same flex properties are fire rated.....gtee 10+ years they stay soft and flexible....that's why they're good for these applications

This is the acoustic caulking I have:

http://www.soundproofingcompany.com/products/silenseal/

For holes through the top plate, my inspector required that I fire caulk these. I did not use the above acoustic caulking and instead used 2 hour fire rated caulking:

http://cableorganizer.com/3m-fire-pr...ier-ic15wb.htm

The fire rated caulking expands when heated. I am unsure if the acoustic caulking does this.

So, does a header need simply to be caulked or be caulked with fire rated caulking?
post #11 of 16
When I finished off a room this year, the inspector specifically looked for fire-rated caulk in any hole in a header. In a wall, you could use whatever you wanted, but headers were a special case. He wasn't going to pass me unless it was fire-rated. The fire-rated caulk I see in lowes here is also colored bright red.
post #12 of 16
Quote:
Originally Posted by etk29321 View Post

The fire-rated caulk I see in lowes here is also colored bright red.

Home Depot sells 4 different grades of it that are rated for slightly different uses. The cheapest, 3M FB 136, is gray and dries very hard (like plastic). It's only intended for framing gaps and not for penetrations made by cables or pipes. For penetrations they sell 3M CP 25WB+ (Red) and 3M CP15WB+ (Yellow). The WB25+ doesn't have any comment about the rigidity / flexibility, but the WB15+ says, "Dries to a firm, rubber-like solid".

They also sell 3M FD 150+ (blue, red, or limestone) is probably the best suited since it specifically states it makes a "flexible monolithic seal". Of course it's also the most expensive.
post #13 of 16
Quote:
Originally Posted by Dennis Erskine View Post

Here's the best you can do (why am I telling people this? geeze, it takes money out of my pocket. Hey buddy, you got a buck for a cup of coffee?)


No kidding...why did I pay money? I could have just waitied until the question came up for free!
post #14 of 16
Quote:
Originally Posted by ctviggen View Post

instead used 2 hour fire rated caulking

Thats what I'll be doing.....saying that, I got some recently for another thing I was making and well, its not nice stuff to work with. sticky, messy and takes AGES to dry......I guess thats the point...but its terrible compared to regular stuff.

Not sure what the consistency of silentseal is?......some people dont care about that stuff, but just a point to note
post #15 of 16
Thread Starter 
All, thanks for the information. Dennis, I owe you a dollar (I think a cup of coffee is now about 8 or 9 bucks at starbucks )

Quote:


When I finished off a room this year, the inspector specifically looked for fire-rated caulk in any hole in a header. In a wall, you could use whatever you wanted, but headers were a special case. He wasn't going to pass me unless it was fire-rated. The fire-rated caulk I see in lowes here is also colored bright red.

etk29321 - For me, the framing inspector checked to see if all of the header holes were plugged with the orange stuff..... which the were...
Or are you talking about the final inspection?
post #16 of 16
I just did the hvac,plumbing and medical gas at a new dentist office, every hole in the top and bottom plate of a wall had to be fire caulked. We never have to do that on a single family home
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