Part 2 of 5 - Building the sound proof enclosure for my air compressor

The plan for the enclosure will be a box without the bottom panel. There will be 1 door on one side for easy access to the compressor when draining it and a lid on top. The compressor will be resting on the concrete floor, as I would think that if it was resting on the enclosure might create more noise due to reverberation and vibration. Making the box is one thing, now we have to design into the enclosure a mechanism for cool air to ventilate inside and the warm air to be let out ensuring the compressor does not overheat as it cycles. All the while keeping noise inside. The lid on top of the enclosure is where the output baffle will be situated. The input baffle is located opposite the side of the door.

Making input and output sound baffles

I have done a bit of research and found several ways to enable ventilation and soundproofing at the same time, and eventually decided that the easiest is to build input and output baffles using the labyrinth method. This is essentially a muffler design which works because sound waves do not like to go around bends, but this is fine for air to travel through. Basically the more bends the better. Shown in the photo is the input baffle/muffler where the inside surface is lined with some noise absorbing foam.


I could have been more liberal with the foam but I ran out. You can also see the round hole I created for the cooling fan. For the fan I used a 240V AC cooling fan. The model I got is a 105 cfm capacity which I got from Jaycar Electronics. This enables the air inside the enclosure to be replaced 5 times every minute, ensuring more than adequate ventilation. The fan is connected so that it pulls air into the enclosure and forces air out through the output muffler. The output muffler is very similar in design to the input baffle, but this doesn't have a cooling fan installed. Just a hole on each end of the muffler. Next photo shows the output muffler with the rectangular airway.


The input and output baffles will now be attached to the enclosure from the inside. I used small angle brackets for these. The next photo shows a hole on the outside of the enclosure. This hole is for the input baffle. So the air will be sucked through this hole, through the labyrinth inside the input baffle, through the fan, then into the enclosure. As there is no other way for the air to go, it then goes out through the output baffle, which is located in the lid on the top panel. I have tested this and it works really well, ventilation-wise that is. I can't wait to see if the sound deadening actually works...