# Filtered sound baffle for dust collector pressure



## need2boat (Jan 11, 2011)

Hello

I'm new to the list, This is one of my first posts so if I'm on the wrong list just point me the right direction. I converted an old 30's style single car garage to a shop in the fall. Considering the small size I decided to put the dust collector, PSI cyclone in a lean to I added on the back.

Fast forward and I'm currently setting things up and I need to deal with overpressure in the lean too and Loss of heat due to the suction. The simple solution is to build a vent into the lean to BUT that will also bring the noise in. I spent a good deal of time insulating to sound proof it. In speaking with someone at the lumberyard they talked about building a filtered baffle between the space.

So I'm wondering does anyone have experience with this. How big the return needs to be? pictures?

thanks in advance.

I have some better pictures of the shop wonder my profile but this is the only one showing the lean too and main building I have at work. It at least gives you some idea of the work space and area where the cyclone is.


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## rieferman (Jan 12, 2011)

Wow, I just checked your rehab of that garage, NICE JOB. From one building saver to another, congrats.

As for the sound baffle idea.. I'm no expert, but I also need to muffle sound to keep neighbors happy. I exhaust outside, which is where the noise comes from in my case. I plan to build a "maze box" (like a line at the amusement park) around my exhaust vent so that the noise has to jog around a few corners before releasing to the open air.

My analogy is that, if I'm yelling to my friend from 15 feet, and then yelling from 15 feet around a corner of my house, in which instance can he hear me better? Sound doesn't go around corners as well is it goes in a straight line.


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## need2boat (Jan 11, 2011)

That's a great Idea. I'm currently venting into the shed and the noise isn't bad. I put rockwool insulation in the wall pls rafters and it really works great for sound. The loss of heat isn't so bad with the cyclone but come summer I'd really like to save that AC when I put in a unit.


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## Pimzedd (Jan 22, 2007)

You might want to take a look at this solution for a shop vac. Scraming shop vac The video lets you hear the difference in sound. I think it could give you a starting place.


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## Viktor (Jan 15, 2009)

Here is a DC muffler idea:
http://billpentz.com/woodworking/cyclone/Muffler.cfm


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## need2boat (Jan 11, 2011)

After looking at the two ideas. I'm thinking I could come thru the wall to either a Box or muffler held vertical to it. Because this doesn't need to be inline like the cylclone muffler I can put it up high in a corner. I like the maze box idea as it can be thiner but I'm wondering about the size needed to offset the vacuum. The pipe size from the Cyclone is 7" down to 6" and then down to 4 at the drops. I was thinking a 7" back should be OK.


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## Dez (Mar 28, 2007)

The more restriction in the return the greater it needs to be in size.
For example -
In my old paint booth with a 24" diameter fan (75.6 sq in) - to a 30 sq. duct (900 sq in - increased because of two right angle corners) I had to increase the area ( for the exhaust filters) to over 9000 sq in to keep the airflow up. 
For the filtered return from my dust collector in an exterior enclosure similar to yours I built a 20" by 40" 
(2 - 20"x20" furnace filters doubled for a total of 4 filters.) I then added a simple "maze box" similar to what you are talking about. It helped but still wasn't as quiet as I would have liked. 
I think adding Bill Pentz's muffler would help a lot!


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## need2boat (Jan 11, 2011)

Dez,

I think I follow what your saying with volume of flow and restriction. But to the maze vrs filter, you think going with a muffler would do better at quieting things down while allowing more flow.

What I'm wondering is this would be used to allow air back into the room where the cyclone is held; do you think it matter which side of the wall it's on. Due to space if I were to build something this size it would most likely need one 90.


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## need2boat (Jan 11, 2011)

I've just started working on finally doing this and decided to add it as a blog entry

here.

Joe


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