soundproofing a compessor hut

[gavuk]

I have a couple of small compressors i want to house outside the garage in a small lean to shed made from louvre door panels 6ftx4off,louvre will allow air in but i would like to reduce noise as much as possible.So what should i try as a sounddeadening material?rockwool?egg boxs?corrugated cardboard? looking for a cheap solution that keeps the neigbours happy...

 

[shenion]

Old carpet works well.

I used some eggcrate foam bed padding on mine.

 

[rtbcomp]

I've put sand on the floor of mine.

Most of the noise comes from the air inlet, so I extended mine using soil pipe, terminating in a box full of foam rubber. This also took the inlet away from the motor and pump and allowed cooler air to be sucked in.

 

[Marty2005]

A few years ago I did quite a bit of research on the subject of soundproofing when number one daughter and mistress of all she surveys, decided she wanted to play the drums and Daddy had to build a 'drum studio' in the back garden. The main features of such a project were to build a 'room within a room' and to use as dense a material as possible. I settled for a dirty great shed inside of which I effectively built another shed. Worked quite well (at least the neighbours stopped complaining). The three main principles seem to be 1) Build a room within a room (or box within a box?), 2) Use as dense a material as you can and 3) Minimise any air gaps as much as possible. If you can translate that into something for your compressor you should be well on the way.

 

[zardoz]

lol, that sounds great Marty, can you get us a pic of it ?

 

[rtbcomp]

Don't forget you'll need to provide cooling.

 

[Marty2005]

Sorry Zardoz, Moved house since then and then bought her an electronic kit which she can play through headphones! The worst thing about drums though is at a gig it's a major construction job setting up and stripping down and I've had to buy a van to cart it all around. I've tried to persuade her to take up the mouth organ.

 

[malcolm]

Few things to look at - structureborne noise, airborne noise (radiated) and intake noise.

Mounting the compressor on rubber feet will help reduce low frequency structureborne noise noise being transmitted through the floor and into the side panels of the shed.

Intake noise is probably a big source. Expansion silencer similar to a car silencer (round shape to reduce drumming) with a decent volume for air to expand, then an exit pipe. Compressor runs at constant speed so it's worth trial and error for the length of the exit pipe and how far it goes into the silencer before welding it on - you can tune them a lot.

For radiated noise you can't seal the compressor in, but would can get a long way with noise absorbing material. Needs to be porous (let air through) and denser stuff is most effective. Thermaal insulation is poor, old carpet would be good. The thicker the better - that's why they use underlay in houses. Thicker it is the lower the frequencies it helps with. It'll help add mass and damp the shed walls too. No need to cover everything.

Sorry - more than you asked for, and what everyone else said too.

 

[gavuk]

Thanks for all the replies,certainly some food for thought,am i right in thinking mdf is better than chipboard if i do a shed within a shed?....carpets and underlay are great cheap ways of soundproofing ,any suggestions should i use the louvre panels to allow air in or not ?,if i build a shed within a shed ,louvre's on outer or inner walls?,had thought of rubber mounting the pressers ,it will be built on a concrete floor,should i bolt a frame down then rubber mount ?sand filled box section?or leave on portable frames and put soundeadening underlay beneath wheels etc planning stage only at moment but greatful for all suggestions.....Gav

 

[eil]

I haven't bolted mine down just rested on old conveyor belts, if they are bolted down vibration carries through to the concrete. I would prefer mdf to chipboard, mainly because I hate chipboard, but whichever you use it would need to be sealed well because of their tendency to soak up moisture.

 

[rtbcomp]

Sealing may reduce the material's ability ro absorb sound.

A friend of mine had a breezeblock garage and decided to paint the walls, the noise level increased significantly.

MDF & Chipboard both absorb moisture.

One idea is to arrange a chimney, easy if you are making a lean-to. This would act as ventialtion and air inlet and the noise would escape at rooftop level.

 

[eil]

the commercial ones look like this

 

[Shug]

How about a mini anacoic (think thats how its spelt) chamber.
They had one at defence agency I worked at. Almost hurts the ears standing in one. Pure silence is very strange!
The pic eil posted looks to have a similar idea with the 'spiky' foam.

 

[Hitch]

We used to make silenced canopys for irrigation pumps. The panes were from folded sheet, then filled with a paper faced rockwool stuff, then perforated mesh over the panels.
20 ft away all you could hear was the exhaust and pump running at tickover.