Sound proof shield vent for dust collector

[Travis Conner]

I'm going to turn an old shelf I built into a soundshield for my dust collector. So i'm assuming that if I put it in a box and seal it up tight it won't work too well since all that air it's sucking up needs to be vented. I'm going to buy something like this, but my concern is all the noise going to just shoot out of this vent, so to act kind of like a muffler i'm going to get some corregated 4" dryer vent hose and make it into an S shape that is secured to the inside of the soundshield to somewhat muffle the noise coming out of the vent. Opinions? I'm not expecting it to be totally silent, but if I can decrease the noise by say 50 percent i'll be happy. Oh and also i'm going to line the inside of the box with acoustic sound foam. What do you guys think?

Now the other simple solution is to just stick both of the dust collectors inside my enclosed "office" inside my shop, but I don't want to put the dust collectors in the same area where my air compressor is since I don't want it sucking up dust, or is this not really an issue?



Here is the vent i'm going to buy. I like the fact that it points downward.

https://www.homedepot.com/p/Everbilt...WHD6/203647465

[Travis Conner]

Or just drill a bunch of holes in the top of the soundshield and the air can "vent" through the foam. That might be a better idea.

[Bill Dufour]

4" is too small unless this is a vacuum cleaner with a 2" hose. Even then it is not big enough. I recommend the effective discharge vents be double the surface area of the inlet. A sound shield will not do much. Sound bounces around a shield. Think of it like water it goes around everthing. You need to enclose the sound in a box so it can not escape except through a baffled vent.
Bil lD

[Travis Conner]

Where should I place the dryer vent? At the top?

[Travis Conner]

Yes I meant to say enclosure. The only part that's going to release sound is the vent.

[Jim Becker]

Always vent an enclosed space intended for sound abatement with a non-direct pathway. That can be a length of (large) flexible duct, a baffled/reverse horn solid duct like I use...anything that is not short and not a direct pathway that can transmit sound waves through the air without them being hindered.

[Frank Pratt]

Always vent an enclosed space intended for sound abatement with a non-direct pathway. That can be a length of (large) flexible duct, a baffled/reverse horn solid duct like I use...anything that is not short and not a direct pathway that can transmit sound waves through the air without them being hindered.

And if you line that serpentine pathway with 1" acoustic duct liner it will make a big reduction in sound.

[Bill Dufour]

Or folks here use a length of insulated flex HVAC duct in a gentle S shape.

[Frank Pratt]

The bigger you make the return air, the better, because that lowers the air velocity. I have an 8" main duct going in & a 6" x 32" sepentine duct for the return air. If you use the same size as the inlet, you'll loose a lot of CFM.

[Travis Conner]

Frank mine has a 6" main intake split into two 4" intakes. I have two powermatic 1300tx dust collectors with a single bag. I'm going to put each dust collector in its own soundproof box.

[Bobby Robbinett]

Would it be possible to build a small lean to and place them out doors? It would be even better if you could let the chips blow out doors as that would increase your performance and solve your noise issue.

[Jim Becker]

Would it be possible to build a small lean to and place them out doors? It would be even better if you could let the chips blow out doors as that would increase your performance and solve your noise issue.

The OP is concerned about noise outside, too...see his insulation thread.

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Travis, I personally wouldn't add complexity to this by putting the two systems in separate enclosures unless they were in different parts of your shop. It doesn't sound like that's the plan. One larger space is easier to vent, easier to clean and easier to build and sound mitigate.

[Travis Conner]

Yeah Jim that's the reason. I want a dust collector at each side of the shop, otherwise I'm just running piping across the whole shop. If I keep them close to the machines I'm using I can just use the flexible hose stuff and be done with it.

[John K Jordan]

Travis,

I also think a large return duct is better for the system.
And there are ways to make the duct better at noise reduction.

I described my enclosure in your earlier thread "Sound proof enclosure...."
To return the filtered air to the shop I built an baffled wooden duct with a large surface area and several turns. I sprayed the inside with a rubber coating and packed fiberglass insulation around the plywood. The sound from my cyclone (5hp ClearVue), deafening otherwise, is quiet enough I can hear a whisper standing directly under the return air duct outside the insulated closet.

I built the duct into the trusses in the ceiling - no photo possible and I didn't do a 3D model but this is the page of the design from my shop construction notebook. There are six changes of direction in the path and several baffles not easily visible in the drawing. Part of the odd shape is to squeezed the duct into the truss space.

Dust_collector_baffle_small.jpg

Another thing some people do to make a cyclone quieter is use insulation around the exhaust duct. Several have used flexible HVAC insulated ducts. I haven't looked at it for years but the ClearVue forum had discussion and information.

JKJ