Well the search was not much help-probably not specific enough.
Has anyone built some type of box around their Ht outlets to control sound?
I am thinking that I can build a surrounding box outside the outlet box that is attached to the sheetrock and stud.
I would feed the wire through the hush box and into the outlet, sealing both with putty.

Any pictures?
MDF or sheetrock boxes?
I could glue sheetrock into a box or MDF.
Just using putty alone seems like not enough for a DD/GG wall, but maybe a box is overkill?
Thanks,
Paul

http://www.quietsolution.com/html/quietputty.html

Putty. Right. Already planning that.

But is it worth hushboxing outlets or would that be only a small marginal improvement?
If worth it, anyone done it?
Paul

I built MDF boxes for recessed lights and for the low-voltage wiring. I plan to just use the quiet putty for the electrical work boxes. I'm using the adjustable Carlon boxes (to account for the double drywall) and I couldn't figure out an easy way to build a box around them without losing the adjustability.

The outlet isn't large enough to be a real issue. the NRC tested this ad nauseum.

Conclusion: before drywall, seal up the holes in the box with caulk.

After drywall, seal up the intersection where drywall meets the box.

Make sure there's insulation in the wall.

PLease don't go crazy with expensive putty and built up boxes. The outlet holes are not large enough to be an issue. While it may be intuitive that the boxes are a liability, lab tests proved otherwise.

http://www.soundproofingcompany.com/index.php?/library/articles/flanking

Of course some of us still built boxes. I just used scrap pieces of wood for the one light switch outlet that is a true wall penetration. All the other lights and power outlets will be built into columns so it's just wire poking through the drywall.

ArmyMan:

I built MDF boxes to enclose my outlet and switch boxes in my theater. I did this on the advice of Bryan Pape, an acoustical engineer that I brought in to help me with my build. Bryan and I spoke at length about putty pads. I kept thinking that I’d use putty pads, as I thought they were just as good. I think I can boil his recommendation down to they are better than nothing, but not ideal. Bryan shared some test results with me that showed that putty pads do little to stop low frequency sounds from escaping. He recommended that I build the boxes, so I did. He is an expert I this area…

I built these boxes with half a sheet of 3/4" MDF and about 6 tubes of construction adhesive. It took about 2.5 hours to build all of the boxes. Installing them took about 3 hours. There are 23 outlet or switch boxes in my theater. Construction was rather straight forward. I used adjustable switch and outlet boxes in my theater, and wanted to maintain the adjustability of the boxes, so your design may vary. The main idea is to build a box to enclose your switch box. This box doesn’t really need to be much bigger than the outlet box, but it does need to be as airtight as you can make it.

The boxes have 5 sides…the 6th side is left off because the stud that you mount it to will actually become the 6th side. The MDF box does need to be flush with the stud to allow for a good seal when the drywall is installed.

Here’s some photos of the boxes:

Single MDF box:
http://i237.photobucket.com/albums/ff52/carboranadum/Other%20Photos/IMG_9923.jpg

Test stud setup with adjustable box:
http://i237.photobucket.com/albums/ff52/carboranadum/Other%20Photos/IMG_9924.jpg

MDF box installed on test stud:
http://i237.photobucket.com/albums/ff52/carboranadum/Other%20Photos/IMG_9925.jpg

Stack of boxes:
http://i237.photobucket.com/albums/ff52/carboranadum/Other%20Photos/IMG_9926.jpg

Boxes installed in screen wall:
http://i237.photobucket.com/albums/ff52/carboranadum/Other%20Photos/IMG_0013.jpg

You will notice that I installed the MDF boxes higher than the adjustable boxes on this wall. When I originally installed the outlet boxes, I forgot to account for the height of the stage. I mounted the MDF boxes, then moved the outlet boxes into the MDF boxes after this photo was taken.

I used construction adhesive and brads to build the boxes, and construction adhesive and finish nails to mount the boxes to the studs. I do have a few tips for those who do this:

- MDF breaks easily. Nailing into it is difficult.
- Drilling through the material requires the use of a backer board to ensure that you do not blow it out. This is key when drilling the hole for the electric cable.
- Predrilling holes for the electric cable is a good idea. You do need to ensure that you know how where the hole for the electric cable needs to be.
- Construction adhesive is really difficult to remove from skin, but not as hard as green glue. :-(
- Use acoustical caulk to seal the hole for the electric cable.
- Don’t forget to put adhesive on the face of the MDF box when installing drywall. It is easy to forget to do this. This seals the box against the drywall.
- Stuff a little insulation between the MDF box and the outlet box.
- Have lots of clamps available to hold the box against the stud for about ¾ hour while they dry.

As with most of the acoustical treatments that we do to stop sound transmission (sound clips, channel, green glue), I wonder how much of a difference it will make. I believe that Bryan’s recommendation is sound (no pun intended). I would do this again, as it was one of the easiest and cheapest things I have done in the theater.

CJ

...putty pads do little to stop low frequency sounds from escaping. He recommended that I build the boxes, so I did. He is an expert I this area…

CJ

That is true if the hole was the size of a vent or a door. Not the case in small holes like outlets. A bending wave traveling through the drwall can't propagate through such a small hole. So this limits our liability to higher frequencies. These are less of a liability if you simple make the box airtight with sealant and have insulation in the cavity.

I'm not looking to enter into arguement, and the boxes look great. But the National Research Council of Canada is the most elaborate acoustics lab in North America and they specifically studied outlets. The conclusion may be surprising, but data is data. All data is online for all to see.

I was as shocked as anyone when I read this research. I myself has used lead to cover my outlet boxes and a 1/2" thick layer of heavy USG sealant.

Ted and CJ,

Thanks both of you.
CJ did your inspector notice or have any comments (or was it not inspected)?
Excellent photos btw.

Ted thanks for recalling the testing. I will probably just seal the regular outlets. Nice to know I can just seal them and skip the putty.
Anything larger may get a box.

Paul

Ted and CJ,

Thanks both of you.
CJ did your inspector notice or have any comments (or was it not inspected)?
Excellent photos btw.

Ted thanks for recalling the testing. I will probably just seal the regular outlets. Nice to know I can just seal them and skip the putty.
Anything larger may get a box.

Paul

My inspector saw my backer box and didn't comment.

The boxes are certainly safe and to code. It wound be different if you were using the MDF box as a stand-alone electrical box.

Also, I would point out that BPape is a hell of a smart guy and I'm at a loss at to whether he's even nicer than he is smart.

I installed these after electrical inspection. The inspectors won't have an opportunity to see these. I did consult a friend who is an electrical inspector in Loudoun county (VA) and he said it would meet code.

I've been really impressed with Bryan and his knowledge. He's been quite helpful in my project. Where I've deviated from his advice, I've done so with the full knowledge of the implications. He's been great to work with as well.

CJ

I will probably just seal the regular outlets. Nice to know I can just seal them and skip the putty.

Paul:

I thought about doing that, but I looked at the back of the boxes and there are four holes that need to be sealed. I sort of figured it would work out better to build the darn boxes than mess with caulking the outlot boxes and the like.

That may work as well.

Thanks for the comment on the photos. I tried to take good photos as I went along because I was certain that this would come up. I'm disappointed that I didn't take better photos of the boxes installed. It was a crazy time...I was working really late to get the room ready to close in and the MDF boxes came up at the last minute.

Good luck on your build.

CJ

Maybe taking so long to finish my room is not such a bad idea afterall! I keep seeing all this new research and new best practices. I was prepared to putty and box my outlets. Now, sealing them is suffucient.

However, the adjustable boxes do seem to be rather "holey." I'm not sure how hard it would be to seal them using a standard 50 year caulk in a gun, but I think would be difficult to get in there behind the box, particularly on outside walls. I'm thinking it would just be easier to use the putty and then be done with it.

I'm thinking it would just be easier to use the putty and then be done with it.

That's the real benefit of the putty. It can be faster to seal up a box.

Speaking of which - Tom did I send you the link of where I got my pads?

Yep. got it, thanks. Was starting think I wasn't going to need it afterall, but think I will use them to take the "faster and easier" route.

Hey Tom,
It seems that you should be able to seal all the holes you won't be using before briging the wire through the remaining hole and before putting the outlet in the box. Then there's only one (or two) left to do.
Of course easy for me to say since I haven't tried it yet!!
Paul

I did a double MDF walled box with GG, for the projector's electrical plug in the ceiling. The GG was there already, and the MDF was leftovers from the in ceiling spot light back boxes.

Putty pads might be faster to do, but the box was maybe fifteen minute's worth of work and zero expense.

Paul -

You could be right, but my boxes are already in place and rough-in wiring passed. So the putty pads around the outside seem easiest.

I boxed mine and sealed all the seams and holes with 50 year silicone caulk (per bpape).
If you are double drywalling, be sure they stand proud of the stud so the first layer of drywall can go around them. Then your box isn't in a massive hole you have to deal with when finishing.

They are just glued together, but when installing, since I had like 15 of them, I installed them by slathering on some liquid nails then just tacking them in place with the finish nailer. This saved a lot of headache when trying to keep them in place when installing.

http://ghause.googlepages.com/outlet.jpg/outlet-medium;init:.jpg

My electrical inspector did not care about the boxing.