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Compressor noise insulation

G-force

G-force

Well Known Member
Has anyone experimented with building an insulated box around their compressor to help muffle the noise? I have a basic design in my head out of 2x4's and plywood, but need something, preferably cheap, that blocks sounds well. Right now I'm thinking several layers of sheet rock (dry wall.) Ideas?
 
Still too noisy.

Yes, when I built my garage I built a small room for the compressor. I insulated the walls and used a solid core door. A bathroom fan is installed in the ceiling of the room that evacuates the warm air. Inlet air to the room is below the solid core door. Carpet was laid on the floor in the room and the inner walls also have noise installation.

Guess what? It's still too noisy and the little room gets too warm.

Had I bought a quieter, belt driven compressor, it would have worked but my direct drive compressor is noisy as &%$#@.

Barry
Tucson
 
Buy a compressor with a large tank so it isn't turning on all the time (it runs for longer periods, less frequently).
 
I have found the large compressors to be quieter in general as well (not only b/c the run less often, but they tend to have larger cylidners and turn lower rpm) A shop I worked at had the compressor outside in what looked like a very tall dog house, that seemed to work well. I've also seen people put them in their attics in home-garages. Whatever you do with it, be sure it has plenty of airflow for cooling.
 
I did!

I built a plywood/ 2x4 box with some leftover fiberglass insulation to provide some soundproofing for my belt-driven compressor. I didn't install any bathroom fans for cooling, but then, I live in Seattle area where I have to heat my shop most of the year. I did install one of those cheap radio shack digital thermometers with a remote sensor so I can watch the temp inside the box. The highest temp I ever saw was around 80*F. Most of the time, unless you're doing some air-intensive work, your compressor will only run for about 2-3 minutes every hour. Cooling shouldn't be a problem. If you're doing air-intensive work, then just open the box door and deal with the noise.

The box reduces sound signifigantly! When the door to the box is open, the running compressor is definitely a conversation stopper! When closed, I can hold a conversation, listen to the radio, and think (not all at the same time though!)
 
Compressor Sound Box

Keep in mind, sound doesn't "like" to go around corners. I made my box out of MDF and lined it with some old (free!) carpet that a carpet store was tossing out. The big secret is the intake and exhaust passages. The in/out passages don't have to be lined with carpet but it helps. The in/out passages are in a serpentine configuration (180 degree reversals). The air moving in/out has to turn two corners before it gets to the main chamber. You could do it with a straight passage each, if you place perpendicular "hurdles" so the air has to weave instead of reverse, but reversal is best.

I've shared this with several friends whose wives and neighbors remain happy. Some A/C's are configured so the internal fan will move enough air to keep things cool. Otherwise, a large ducted fan like at the rear of a computer, (but larger) bought surplus, works well.

All this being said, I recently ditched the 230V compressor for an Axial or Scroll type unit - which doesn't need the box (the "other" alternative).:)
 
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I found that taking off the intake filter, creating a snorkle, then putting some sort of silencer on the intake really helped reduce some of the noise. As previously mentioned, it's the intake/ exhaust noise that is a big contributor.
 
I'm real happy with my compressor box I built. I did a combination of Dan Checkoways box and a drawing I found on the internet. I built it out 3/4 inch plywood and lined the inside that thin bumpy foam mattress cover stuff from Walmart. The foam really cuts the noise. Here's my write-up:

http://www.smittysrv.com/more_stuff.asp?ID=7

PS: I should have gotten the oiled compressor!
 
I built my box out of particle board, then lined the interior with scrap carpet pad, then rubber mats, then carpet (all have different absorptive characteristics). Intake and exhaust was done as a duct lined with carpet. Lid was made quite heavy with 2 rubber seals and over center latches. Nice and quiet.
 
NOISE?

The new Sears two stage is so quiet, when it is running you can stand next to it and carry on a conversation. I can even hear my cell phone calls. The rivet gun is much louder. Pricey but real quiet. My 2 cents.
 
My compressor is located at the front corner of the garage. Noticeably quieter when the door is open. Probably less hard surface area for the noise to bounce off. For the next step, I may put some carpet pad and scraps on the wall next to the compressor. With a 60 gallon tank, there isn't much space to box it in.

I had read that a very large portion of the compressor noise is from the intake system. So I bought 2 lawn mower mufflers and put them on the intakes. Hardly made an improvement--you would need a meter to know for sure. I checked with a compressor shop & they sell intake mufflers, but the sales guy said they would only help about 20-30%, and at $65 per cylinder, 2 cylinders, I didn't think it was worth it.

At this point I am just putting up with the noise. When it bothers me too much, I put on my Peltor AM-FM radio headset & listen to tunes. Good for riveting noise suppression also.

If you do box in your compressor, remember to provide access to the drain.
 
Best money to invest in compressor noise is to buy a 2-stage compressor. My 80 gallon 2-stage has been running quietly for about 19 years now and I can talk while standing right next to it. I drain the water every day and change the oil and intake filter once a year.
 
compressor noise

I agree that large compressors are quieter. In my line of work we had to locate a compressor in a small janitorial closet (slop sink etc.) Very small room with tile walls, perfect for bouncing the sound. Close to this room was located the office of a particularly pompous %&#% (mule) who continuously complained about the noise. This compressor ran very infrequently. My solution was to use egg shell sound proofing material. It comes in 4X8 sheets. You can cut it with a box cutter and glue it up with construction adhesive.
It runs about $70 a sheet if you shop the internet. The guy that complained was such an idiot that in order to cover our #$%&( 's we used a decibel meter before and after the material was placed. There was a noticeable difference, as I remember about 8 points less on the meter. From a human ear standpoint, we were pleasantly surprised at the lowered sound level.
Just a thought.
Mark Wyss
RV4 fuselage skinning
 
Was at Lowes today & saw they had acoustical ceiling tiles, 2'X4', $29.95 per case. I didn't need a case, but they had 3 sheets sitting there with corners damaged. I asked if they would do something on them & they guy said he would sell them for 50 cents each.

Will probably build a box out of the stuff to go around the mechanical parts with a vent hole in the top. Left over pieces will probably go against the wall behind the compressor. I don't have space around the compressor to build a cabinet around it.

So now, we'll see how that works out.
 
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