Soundproofing a generator

[the-gnole]

This will depend on how big the genny is and how much room you have to work with and what restrictions you want to impose as to looks and the neighbours might think.

First thing is to insulate it off the ground, two pieces of a closed cell camping mat cut to size on the deck to start with, a 25 - 50mm layer of rockwool in chicken wire cage goes on next, then another double layer of foam mat, if possible fix some battens through the top layer to another couple of counter battens on top of the rockwool, this will give you something to fix the genny to so it doesn't bounce around too much.

Next is a wooden box to go around and over the whole unit with about 100mm "air space" inside it.

Drill some 50mm holes around the sides and the top of this box, try and do it in a uniform manner but do not over do it as you will need to put another box over this with more holes in that don't correspond to the first lot.

you need to make this second box shorter than the first one and have spacing battens inside to keep them apart, then using more rockwall create baffles but that also allow some air movement.

Lastly another box over the top with a solid lid to keep the rain off, and a couple of slatted sides.

If you want you can add a long extension pipe of about 100mm for air in and an extension tube of at least one size bigger for the exhaust going to a high spot.

These are my plans for creating a soundproof box for my 1.9 diesel genny, I'll get back to you when it is completed.

[Carrot Cruncher]

With pics

Can you explain a bit more about how you are fitting the baffles

then using more rockwall create baffles but that also allow some air movement.

I'm probably just be being thick and not concentrating...i'm playing poker online at the moment and losing

[the-gnole]

It will become apparent when I get the photos done

[Carrot Cruncher]

It will be interesting to compare the 2 different methods when they are completed. I might see if I can borrow a decibel meter to measure the before and after

[metatron]

I've found one of the best ways is to build or buy a metal hut (the kind they sell to hold tools or bikes) that can fit your genny with room around for air movement.

Run two lengths of metal pipe out the side, one for clean air one for the exhaust.
On the air in pipe fit a cheap PC fan to push air in.
Fit a exhaust pipe to the genny.
Fit an expansion chamber (you can make one out of an oil can)
Fit a length of pipe coming from the expansion chamber to the exhaust pipe going out the metal hut.
Line the whole hut with Dynamat or SoundX (cheaper but not as good)

If you don't want to hear it at all and want to make it look nicer, build a wooden case around it leaving a 3 inch air gap.

[Carrot Cruncher]

An update on my genny shed

I just got the genny shed in a position to fire up the genny. The shed is only 1m x 1.2m in size. I went down the heath robinson route of lining it with the cheap tarps to give it some more waterproofing, then a couple of layers of carpet, with a thick layer on the base. My original plan was to also add some of the rippled underlay as a final layer on the walls and roof but it is too heavy to be supported by screws etc and they just pull through under the weight. I might get some sheets of the dimpled foam that is often used for packaging but for the moment I thought I would give it a try as it is

I haven't sorted the cooling (I may just plug a desktop fan into the genny short term) or the ventilation for the exhaust.

The reason I used carpet was that I had plenty around so there was zero cost

Results are a very unscientific 40 - 50% drop in the noise level. It takes it fom being effin loud to being quite noticeable but not too bad. It shouldn't annoy any neighbours except maybe the next door neighbours if it was being run in a powercut, but if they moan I wont let them store any food in my freezer . It would still attract far too much attention if ts ever htf but as its much more likely to be used for general outages it should be ok.

I tried fixing an old scooter expansion chamber to the exhaust but it made very little difference (although the chamber wasn't in the best condition), most of the noise seems to be general engine noise. I will have to run the exhaust outside of the shed so may try burying it into some pebbles which apparently helps

At least now it is in a useable state and hopefully when I fit the foam it will reduce the noise further still

Will post some pics when I have added the foam and tidied up the work a bit

[JohnRio]

This will depend on how big the genny is and how much room you have to work with and what restrictions you want to impose as to looks and the neighbours might think.

First thing is to insulate it off the ground, two pieces of a closed cell camping mat cut to size on the deck to start with, a 25 - 50mm layer of rockwool in chicken wire cage goes on next, then another double layer of foam mat, if possible fix some battens through the top layer to another couple of counter battens on top of the rockwool, this will give you something to fix the genny to so it doesn't bounce around too much.

Next is a wooden box to go around and over the whole unit with about 100mm "air space" inside it.

Drill some 50mm holes around the sides and the top of this box, try and do it in a uniform manner but do not over do it as you will need to put another box over this with more holes in that don't correspond to the first lot.

you need to make this second box shorter than the first one and have spacing battens inside to keep them apart, then using more rockwall create baffles but that also allow some air movement.

Lastly another box over the top with a solid lid to keep the rain off, and a couple of slatted sides.

If you want you can add a long extension pipe of about 100mm for air in and an extension tube of at least one size bigger for the exhaust going to a high spot.

These are my plans for creating a soundproof box for my 1.9 diesel genny, I'll get back to you when it is completed.

If only my one-time boater neighbours would've done this! Sound carries far too well on the river!