Part 4 of 5 - Building the sound proof enclosure for my air compressor

Google is my friend

When I embarked on the task of sound proofing/noise reduction for my air compressor, I didn't really know anything about sound proofing. I thought all you needed to do was to put it inside a box and then that's it. Little did I know that there were quite a lot of details to learn and apply to effectively soundproof my enclosure. And I thank Google for facilitating all my research. As there were several things that you can do to combat noise, I decided to apply a multiple-pronged approach.

SOUNDPROOFING AN AIR COMPRESSOR

Use of a sound barrier material

Firstly I decided to use 18mm MDF as the walls for the compressor enclosure. From my Google research, I found out that MDF had an STC rating of around 29, which is pretty good. In addition to this, I also used mass-loaded vinyl (MLV) , a heavy vinyl sheet which I attached to the inside wall of the enclosure. It is also known as a Flexible Noise Barrier. Here in Australia, I used an MLV marketed as WaveBar from Pyrotek. This thing is heavy at 8kg per square meter, and that's why it works. It is also very easy to apply, I just used screws for fixing to the inside wall. This material has an STC rating of 30. I got the WaveBar roll from Clark Rubber.

The photo shows the inside of the enclosure lined with 8kg/sq. meter WaveBar.

Use of a sound absorption material

I got these MLV + Acoustic Foam from Jaycar Electronics. They did not say what it is, but they look very much like WaveBar, although it is not that heavy at 4.5kg per square meter. I used some of these as they are laminated to acoustic foam material, which helps in absorbing sound to get rid of reverberations and echo. The foam would also have a dampening effect on the MDF.

Use of vibration dampening material

I got some vibration dampening rubber pads from Clark Rubber. The air compressor do not have direct contact to the concrete floor of my workshop. Surprisingly, you can actually hear the difference straight away after using these.

Input and Output sound deadening baffles or muffler

If you have read my previous post, this mentioned about using a labyrinth design for the input and output muffler. I had also used some acoustic foam in the inside surfaces of the muffler to control echo.

Use of Intake Filter Silencer

The intake side of the air compressor is what makes the most noise. To combat this, the Intake Filter Silencer was invented. It works the same as an exhaust muffler, only the air direction is in reverse. Same principle, let air pass through, but block sound. I did some inquiries, and found out that my choices for intake filter silencers are limited here in Sydney. The first is the silencer from a company called Solberg. They can be available in Sydney, but the bloke I spoke to on the phone wasn't particularly helpful so I tried another company.

Next I inquired about the intake filter silencer from a company called Allied Witan , called Atomuffler Filter Silencer. I couldn't find any literature about the amount of sound it attenuates, but it works, and it works really Good. Surprisingly Good.