Cone of Silence

[Larry Cooke]

I'm wanting to build a sound proof closet (dome of silence :)) for my DC. I'd like it to be as sound proof as possible.

When I did an addition to my house I tried my best to sound proof things like the bathroom and so on, but I missed the mark. You can still hear things through the wall. I used black board and insulation which I know helps but there has to be something better.

I want to run my DC without worrying about waking the whole how up late at night. What are the best methods for sound deadening? Anyone out there that's done it with success?

Larry

[Bill Lewis]

Larry, to toally soundproof you could follow the lead on what is done for home theaters. You can go all out and use double stud walls to isolate inside surface material from the outside and insulate between. Double the drywall for more mass. There is also drywall isolation mounting bars that you could use. Also hang sound deadening material on the inside such as an open weave fabric padded panels, or old carpeting.

[lou sansone]

Larry, to toally soundproof you could follow the lead on what is done for home theaters. You can go all out and use double stud walls to isolate inside surface material from the outside and insulate between. Double the drywall for more mass. There is also drywall isolation mounting bars that you could use. Also hang sound deadening material on the inside such as an open weave fabric padded panels, or old carpeting.

I agree with bill. I do think hanging the sound material on the wall will be a big help. places like mcmaster carr sell it. I lined the inside of my planer with some if it and it did quiet it down ( 12 hp motor does make some noise )
lou

[Chris Barton]

One of the issues you will run into is the fundamental physics of sound. Low frequency sounds penetrate solid structures. That why you here the bass end of the rap song a guy in a car 200 yards away from you in traffic is playing. Higher frequency sounds are fairly easy to dampen. Also, solid structures transmit sounds so, you would have to look at some of the devices now available that allow you to put a floating skin over studs and doing what Bill suggests about double walls.

[Chuck Saunders]

One more question to consider, where is the air going? After all that is where the lions' share of the sound is coming from. It is kind of like silencing a heliocopter, the noise is from the wings moving through the air. With a DC, the more you duct the exhaust to baffle the sound, the more back pressure you create and the lower effectiveness of the DC. I suppose that if you sound proofed the DC closet and ran the exhaust through a large insulated duct to lower air speed with a 180 or 2 bend that might quiet it down.
My $.02
Chuck

[Bartee Lamar]

Rock Wool insulation....

User different materials in layers for wall covering. Each kind of material has different absorbtion frequencies.

Remember, sound go where air can go... so fill ALL the cracks.

Decouple anything you can from any part of the house. Sound is virbrations, so if something will transmitt vibration it is NOT good.

Look at this site http://soundproofing.org/

Also Google for sound proofing materials...

Lots of info....

[Jim Becker]

My DC closet is pretty effective...2x4 construction, drywall on the outside, fiberglass insulation between the studs and 1/4" peg board installed rough side exposed on the inside. The return air duct is a folded arrangement to prevent direct transmission of sound. I could have built the closet with more "sound technology", but have been very pleased with this arrangement...and it was inexpensive.

[Kent Fitzgerald]

As others have said, there's no way to 100% soundproof a DC. You need a pathway for air flow, and a path for air is a path for noise.

What kind of DC are you using? I have a cannister/plastic bag setup, and a lot of the noise is from debris swirling in the plastic bag. I've thought about using something like an impermeable canvas bag (AFF sells them) to quiet it down.

Penn State Industries also sells a muffler that goes between the blower and filters.

[Larry Cooke]

Great suggestions everyone! The link to soundproofing.org will help.

Guess I should have mentioned that I'm considering the Onieda 2hp Super Gorilla for my DC. And to be honest I hadn't thought about the fact the most of the noise will be coming from the exhaust side of the unit - though I'm sure a fair amount of noise will come from the motor and blower too.

I really don't want to restrict my air flow and putting this outside of the shop isn't an option (track housing and the neighbors might get a little upset with me...)

I'll talk to Onieda when I place my order and see what the best trade off might be.

Jim, I'm not sure what you mean by your return air duct. I'm assuming you have a vent to the outside in one of the walls and that system is folded? Your solution may be the best for me. I know I can't eliminate 100% of the noise but if I could reduce it by 50% I'd be real happy.

Thanks again everyone!

Larry

[Lee Schierer]

Just be sure that your DC motor will have adequate ventillation. A closed up closet can get pretty warm for the motor. Here at work we observe that 90% of the noise can get out of a 5-10% hole, so sealing up almost all of the openings and not all of them can still release significant levels of noise.

[Denise Ohio]

Lee is right. Heat can be a huge issue.

I've never soundproofed a DC, but I've soundproofed studios and iso (isolation) booths. Eggcrate foam is inexpensive and works well, but the closet will get warm. But you can use old shag carpet stapled on a 2x4 frame to absorb some of the sound. And add a bit of splashy color to your DC room.

You can also put devices on rubber washers to dissipate some of the sound, especially the low-end. Recording rooms will build the floors on rubber gaskets for this reason. You can even put the same lovely shag carpet of the floor for more absorbtion.

Another good trick is to not have the room be a square. For example, you can have the abovementioned shag carpet wall set at 10-15 degrees from the wall (even a little bit of an angle will help). This will put air space between the hard surface of the wall (will help dampen the sound), plus the shag will suck up some of the energy (groovy), and any energy left will bounce at an angle to any other surfaces without adding to the existing pressure waves.

If you google eggcrate, iso booth, etc., you will find zillions of companies that sell eggcrate. Guitar Center sells soundproofing in a box that glues on quite nicely to just about any wall. The set comes with baffles that do pretty well with low frequencies.

Good luck.

[Dennis McDonaugh]

Missed it by "that" much. Sorry I couldn't resist since Get Smart was one of my favorite shows when I was a kid, but I think it was a cone of silence.

[JayStPeter]

Stick with soundproof.org. My basement workshop itself is "soundproofed" from the rest of the house. I used insulation, resilient channel in the ceiling and staggered stud walls to separate my shop from the other half of the basement. Isolation is the key, things like eggcrate foam are more for in-room sound treatment (ie killing reflections within the room, useful in a music studio or theater ... not much use in a DC closet). Not to mention the impracticality of eggcrate foam in a dusty shop environment. Plain 'ol insulation is equally effective for removing transmitted sound. The problem with either one is that the studs themselves transfer the sound waves directly to the outside of the closet. You must isolate the inside wall from the outside wall (resilient channel and staggered studs are two reasonably priced ways to do this).

I did build a closet around my DC that is somewhat helpful. However, a lot of the noise comes from air traveling through the DC ductwork. Even though I close the (solid core) closet door and it helps, it still isn't pleasantly quiet. I wouldn't spend too much effort on it personally. If I was to do it again, I probably wouldn't bother with the closet. If you want to work in the shop while the family sleeps, spend your effort keeping ALL the sound in your shop. A planer or router is much louder outside the shop than a DC. I could leave my DC on all day without closing the closet door and you'd never know upstairs. But get my planer or router ripping into some lumber and you can tell I'm in the shop. It's not loud, but you can still hear it upstairs.


BTW, the return air bit Jim mentions is how he gets the air back into the shop from the DC closet. The DC sucks it in and must do something with it so you need an air return path to the shop similar in size to your intake pipe. By making it "kinked" the air gets back out without all the noise coming with it. A kinked path can also be used on an air conditioning duct if necessary. Air conditioning ductwork will transfer all your sound to the rest of the house. So, it must be isolated as well. I put insulation around mine and removed the ducts from the shop (for now at least). Since the ceilings are isolated from the floor joists and the ducts are connected to the joists, the ducts are isolated from the shop.

Jay St. Peter

[Larry Cooke]

Just be sure that your DC motor will have adequate ventillation. A closed up closet can get pretty warm for the motor.Good point Lee.


Another good trick is to not have the room be a square. For example, you can have the abovementioned shag carpet wall set at 10-15 degrees from the wall (even a little bit of an angle will help).By default, where I want to locate the unit it may end up being almost a triangle so this could lend itself well towards your point.


Missed it by "that" much. :) Corrected it! Thanks, guess my memory isn't what it used to be. I too enjoyed the show.

Larry

[Larry Cooke]

I did build a closet around my DC that is somewhat helpful. However, a lot of the noise comes from air traveling through the DC ductwork. Even though I close the (solid core) closet door and it helps, it still isn't pleasantly quiet. I wouldn't spend too much effort on it personally. If I was to do it again, I probably wouldn't bother with the closet.You, know the more I read into what everyone is saying, it might be a better idea to not do what I had in mind.

Pluses: Maybe a small amount of noise reduction.

Minuses: Reduced effeciency in the DC, higher operating temps for the motor, additional money (and time) to build it, and possibly making maintenance more difficult.

Sound proofing the shop does make more sense, though I already have drywall up but I did insulate it very well. That will definately help some. At the very least my shop stays pretty mild year round even here in the desert.

I'm afraid I'm just going to leave well enough alone. Thank you very much everyone! I think I may saved myself some money and time.

Larry

[Steve Clardy]

what about double drywall in the dc room?

[Larry Cooke]

what about double drywall in the dc room?I thought of that too Steve. It all comes down to the fact that in order for it to be sound proof, I'm going to have to seal the closet amongst adding deadening materials. With a sealed closet the DC won't have any airflow, in other words it will cause serous back pressure. Also, the motor will likely overheat.

I'm hoping someone will come along and say "how about doing this or that way" but to be honest I don't see how it can be done without making some major sacrifices to either performance, life of the unit, or both.

Thanks for the suggestion!

Larry

[Dave Fifield]

Larry,

I know a fellow called Ethan Winer who is an expert at sound treatment and isolation. He runs a forum here, at Music Player (http://www.musicplayer.com/cgi-bin/ultimatebb.cgi?/ubb/forum/f/26.html). He has some FAQ stuff that will answer nearly all your soundproofing questions.

Cheers,
Dave F.