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What have you lot used to keep the noise down from your compressor?

I've got a 200L, 3Phase compressor up on the big shelf above my bench and I want to quieten it down. The noise doesn't bother me in the workshop, and can't be heard from the farm house... but there is a house not to far away behind the unit which I don't really want complaining! During the day is not a problem, but late evenings its probably a bit antisocial to have it going!

I'm thinking for now that all I need is some of the egg box shaped foam stuck to the back wall around the compressor and on each side? Thinking that leaving one end open should provide enough air flow to keep it cool?

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Any soft lined enclosure will help to some extent, but bear in mind that where the is an air gap, noise will escape.

I found a Hyrovane makes the biggest difference:p

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I appreciate any gap will let sound out, but I'm trying to reduce the sound that goes towards the back of the unit, sound from the front of the compressor isn't a problem.

Hydrovane would be lovely.... but this compressor was a good deal! Hydrovane was looking to be around the £3500+Vat when I bought my piston one.

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How about some silencers on the air intakes? and mounting it on rubber - you could use engine mounts . And make sure the Shelf it's on is nice

and rigid , it's surprising how vibration will travel and translate to noise .

A couple of years ago I mounted my 'shop comp. onto 3 pneumatic tyres so I could drag it around the yard , it's lots quieter just from that

cheers

Steveb

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suggestion...

You could look at the mountings too... is it on rubber mounts?

http://www.ebay.co.uk/sch/i.html?_sacat=0&_nkw=vibration+mount&_frs=1

It is possible that the noise is being tranmitted via vibration to the wall, and that in turn is vibrating like a speaker of sorts and transmitting the noise external to some degree.

The egg box foam can work (to a degree), but what you probably want to do is apply it on all 6 sides..... (top, left, right, front back and below).... yes at this point you're thinking what about airflow....

What you need to do is think about this, noise likes to travel in line of sight, if does not like to travel around corners.... if you offset the foam at the ends to allow airflow, but still provide a baffle (say offset it 300mm, but allow for a 200mm oversize piece on each end, then the soundwaves that hit it will be adsorbed to a degree before they are reflected).

The other problem with noise is the octave band where it occurs (low tone or high tone), to get rid of high tones is fairly easy (a reasonable foam will do that / rubber type foam), the problem is the low tones as they need dense material that absorbs the sound but does not move....

The good thing with the low tones is they do not travel well with distance...

I'd look at the mounts first, then apply some foam, have a look and see if you can apply some insulation to the roof of the garage as that will absorb the sound

(my neighbors don't complain with 3am two compressors and an angle grinder running (but I am near a train track too..., so noise tolerance is higher)

Rob

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Its already sat on some nice rubber mounts.... and there is (from memory) no noticeable vibration at all through the shelf. For those that haven't seen the build of my 'shelf' over the bench.... it is solid!

Good ideas on having the end panel offset, hadn't thought of that.

Something that makes a big difference to the noise, is putting a hand on the tank.... I think the noise of the air compressing is magnified in the big tank.... Wonder if it would help if I wrapped that in something?

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Something that makes a big difference to the noise, is putting a hand on the tank.... I think the noise of the air compressing is magnified in the big tank.... Wonder if it would help if I wrapped that in something?

... no expert on this subject, but what you may find is that your body / arm being a rigid / dense object is probably absorbing the sound think of it as a shock absorber if only momentarily....

The receiver in it's shape is also a good amplifier of noise.

Suggestion (never tried it....) see if you can get a piece or rubber / foam and put it between the compressor and a couple of bricks / block) it may act as a sound absorber .... not got a clue if it would work, but if you have some foam that you're going to use for the enclosure and a few bricks or blocs about it may work as a dampener.

Offset end panels want to be a bit larger than the hole, what your're trying to do is make the noise travel around corners, which it does not like to do and provides a degree of attenuation.

..... from memory ,if you have sound on one side of a wall and stand on the other side of the wall the rough sound reduction is about 6dBA if all the dimensions are equal... (3m wall, 3m from noise source to wall, 3m from wall to receiver (where you're standing), likewise as you get further from the noise source it obviously dissipates the noise level (but at 3am in a quiet location the ambient noise level will be very low so trying to reduce a compressor from ~95 dBA to about 30 ~ 35 dBA requires ... distance + obstructions to the direct sound path + a sound deadening material (attenuation).

there is a bit here I think (not read it ... just the noise level decreases by 6dBA for a doubling of the distance), i.e. if you measure a noise as 95dBA at 1m, at 2m it will be ~ 89dBA, and at 4m it will be ~ 83 dBA, and at 8m it will be 77 dBA, and at 16m it will be 71 dBA (etc etc) ... roughly....

http://www.sengpielaudio.com/calculator-distance.htm

(this isn't my day job... but it may give you ideas / guidance).

Rob

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All very useful information Rob. I've only tested the noise by setting the compressor filling from empty and walked down the track towards the house.

I hadn't remembered the bit about the dB level dropping with distance, but is a useful one. I think I need to get hold of some foam and experiment!

Something to dampen the tank is a good idea... I've got some rubber and there are bricks laid about the farm!

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.... you may find is that your body / arm being a rigid / dense object .....

I'd not let him talk to you like that Ross! Calling you a dense object ... tsk tsk :P

I take it you've checked it's not something stupid like the belt guard rattles or perhaps resonates? Is the belt correctly tensioned?

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I'd not let him talk to you like that Ross! Calling you a dense object ... tsk tsk :P

Haha...

We all own a "proper LR" don't we? (lets not have a leafer / coiler debate, and end end of the day they all lack creature comforts... (like heating & water proof!)) ... have to be dense to own a LR .... I was once admiring a Lamborghini, and someone said to me" the only reason he bought that was because he could not afford to run a landrover". I smiled and walked off, but the thought has stuck and probably rung through in the end (15 years ago!)

Rob

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What have you lot used to keep the noise down from your compressor?

I've got a 200L, 3Phase compressor up on the big shelf above my bench and I want to quieten it down. The noise doesn't bother me in the workshop, and can't be heard from the farm house... but there is a house not to far away behind the unit which I don't really want complaining! During the day is not a problem, but late evenings its probably a bit antisocial to have it going!

I'm thinking for now that all I need is some of the egg box shaped foam stuck to the back wall around the compressor and on each side? Thinking that leaving one end open should provide enough air flow to keep it cool?

What noise?

Sound's like you need a quieter compressor you say, sorry you need to SHOUT ^_^

Try a Hydrovane compressor, I have a HV-02 3hp Single phase that has a FAD of 7.9cfm (or about 12 CFM equivalent of piston compressor) that has a noise level of 62 dBA with no enclosure (that's quieter than normal speech at 3ft)

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I built one out of plaster board, theres a hole in the bottom and some smaller in the top. Its about 3-4 layers thick. Oviosly this isnt finished and it has a door now etc. I think plaster board is the right material cheap and dense you can get the more sound proofing plaster board but its three times the cost last time i looked.

Id like in the future to take the compressor of the tank and then just have the compressor in a smaller/thicker box.

Ben

post-13761-0-11030300-1430982478_thumb.jpg

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i have boxed mine in with old kingspan that i had lying around. much quieter, although im sure something like eggbox foam or maybe even rockwool would be better. rockwool may keep it dustier in there though?

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  • 3 weeks later...

I have both my compressors (3hp v-twin 9.6cfm each) boxed in with 100mm Kingspan left over from my house build. It is a lot quieter in the shed, but I have air vents on the outer wall to provide a fresh air supply which does allow some noise to escape...my nearest neighbour is over 1/2 a mile away so no worries there.

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