# Quieting the Generator



## HamiltonFelix (Oct 11, 2011)

We have a little sort of doghouse style generator shed next to the house. When I got it, the back was open and it was right up against the house. I screwed a sheet of OSB onto the back and moved it a foot or two away from the house. That helped. 

We buy eggs in pretty good quantity at places like Costco or Cash & Carry (caters to commercial kitchens). We end up with a bunch of those cardboard sheets that they put between layers of 30 eggs. We repackage into our saved standard one dozen egg cartons at home, so we have little use for the cardboard separator sheets. We noticed the similarity in appearance to what you see on the walls of an anechoic chamber. We're thinking of stapling these onto the inside of the generator shed. 

Any thoughts? 

Of course, if we want to do the experiment scientifically we'll need a decibel meter to measure before and after.


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## IlliniWarrior (Nov 30, 2010)

most likely you're adding tinder to a future fire ....


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## Coastal (Jun 27, 2013)

I agree...and think you are nuts putting anything flammable near a generator room. Steel studs, rockwool insulation, gypsum board and perforated steel sheets are how you quiet a generator room. Not flammable leftovers.


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## camo2460 (Feb 10, 2013)

I don't know much on this subject, but couldn't you add a small muffler to it?


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## HamiltonFelix (Oct 11, 2011)

Good points. Wouldn't want that cardboard or any foam sheets anywhere close to hot parts. 

When running, the door on the side away from the house is open for air. I do agree a quieter muffler would make a difference. The generator I'm using at present has a 10 hp Honda engine. Maybe I should research a bit and see if there's an automotive muffler that would silence it without adding back pressure.


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## TheLazyL (Jun 5, 2012)

IlliniWarrior said:


> most likely you're adding tinder to a future fire ....


I'd agree.

Why not use fiberglass insulation instead?


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## HamiltonFelix (Oct 11, 2011)

That's a thought. I may have some leftover bits of insulation from work we did on the house. The egg crate thought was just because the shape reminded me of the walls of an anechoic chamber. But if the material isn't right, that won't work anyway. I suppose a layer of anything soft will help. I'll look around the place. It's not terribly urgent, but I'd rather not listen to the generator when we're using it.


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## Coastal (Jun 27, 2013)

i don't think your run of the mill fiberglass insulation is dense enough to make much of a difference. There is a lot of science behind sound reduction.


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## TheLazyL (Jun 5, 2012)

Coastal said:


> i don't think your run of the mill fiberglass insulation is dense enough to make much of a difference. There is a lot of science behind sound reduction.


I used fiberglass in the bathroom walls. Worked wonders in killing sounds.


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## Boomy (Mar 17, 2012)

camo2460 said:


> I don't know much on this subject, but couldn't you add a small muffler to it?


Yes you can. 
http://www.jackssmallengines.com/noisy.cfm

http://www.booneyliving.com/935/how-to-quiet-a-generator-to-tolerable-sound-levels/

http://joelsgarage.blogspot.com/2006/03/quiet-generator-muffler.html

http://www.alpharubicon.com/altenergy/gensetquiet.htm


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## drgnhntr37 (Apr 13, 2012)

We had a noise problem at our hunting club from generators running. We solved the problem by using a stealth muffler for an atv. Bolted right on and them added a section of pipe straight up about 10 feet this virtually eliminated the noise. 


Sent from my iPhone using Survival Forum


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## HamiltonFelix (Oct 11, 2011)

Thanks. Lots of good ideas here. Now to find time to experiment.


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## Stuwee (Jul 10, 2012)

Saw a program on STONE WOOL insulation last night. Looks like that would work just fine for what you're trying to do.


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## LincTex (Apr 1, 2011)

Adding a muffler only helps exhaust noise. There's a LOT of "other sound" coming off that isn't just exhaust noise.

Get a bunch of cinder blocks and stack them around the machine to make an enclosure; that will help with sound a LOT and isn't combustible. You can store the cinder blocks in the far back corner of the yard when you aren't using them.


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## Coastal (Jun 27, 2013)

TheLazyL said:


> I used fiberglass in the bathroom walls. Worked wonders in killing sounds.


Killing the sound (and smell) of you dropping a deuce in the toilet is hardly a comparison for quieting a generator.

I speak from experience, not internetting.


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## TheLazyL (Jun 5, 2012)

Coastal said:


> Killing the sound (and smell) of you dropping a deuce in the toilet is hardly a comparison for quieting a generator.
> 
> I speak from experience, not internetting.


Sound reflects off of solid objects. Noise.

Sound is absorbed by soft objects. Quiet.

Surrounding a generator with hard cement blocks will redirect the sound upwards (assuming no roof).

Surrounding a generator with soft fiberglass insulation will deaden the sound with minimal redirection.

Same principle applies to plop plop tingle tingle. I was amazed when we remodel the bathroom in our old house how much quieter it was.


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## helicopter5472 (Feb 25, 2013)

Plus a generator has to have airflow for cooling so it needs some opening/exit somewhere....


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## Caribou (Aug 18, 2012)

If you start with a quiet generator it helps. The Honda EU2000i is pretty quiet.

Fiberglass does a decent job with sound attenuating. A second insulated wall about an inch in from the first is even better. The studs will carry sound so the break really helps. You can even put a layer of soft fiber board, loose, between the walls.

Put on a larger muffler. Wrap the muffler and pipe with insulation. Run the exhaust straight up a few feet so the sound is directed away from anyone. I've put enough insulation on boat exhausts to know that it helps with both heat and sound.


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## Jason (Jul 25, 2009)

My first thought was the fire hazard, too. Even a stray spark from the muffler could be enough.


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## helicopter5472 (Feb 25, 2013)

Get a longer extension cord and tap into the neighbors, that way if there is a fire everyone will blame him...Ha ha saves gas too.


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## readytogo (Apr 6, 2013)

depending on the type of generator(brand of engine) there are many ways to cut on noise,removing the muffler and making a nipple in its place you can then extent the pipe or flexible tubing to an outdoor area and re-attach a bigger muffler or 



 or like in the army we had an extension pipe with the muffler in a pit cover with rocks for night use.


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## LincTex (Apr 1, 2011)

Burying a barrel underground works amazing for quiet exhaust. You'll see this in the instructions for very old standby power plants.

Still have to make a quiet enclosure for the machine, though.

http://www.smokstak.com/forum/showthread.php?t=15267

http://www.utterpower.com/muffler.htm

http://listerengine.com/smf/index.php?PHPSESSID=d503c95ac815cf1a7f45ecea3fce3649&topic=560.0

http://greenspun.com/bboard/q-and-a-fetch-msg.tcl?msg_id=000edQ


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## readytogo (Apr 6, 2013)

*Some ideas and warnings on generators*

http://www.booneyliving.com/935/how-to-quiet-a-generator-to-tolerable-sound-levels/


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## Tex (Oct 31, 2008)

Off hand.

After a muffler, route your exhaust in an underground metal pipe into a square metal duct. The duct is lined with sound absorbing baffles kind of like egg crating. The ground should have cooled the exhaust by the time it gets to your ductwork muffler. Route it above ground into a sound deadening enclosure.


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## LincTex (Apr 1, 2011)

mike_dippert said:


> An idea I've been throwing around my head. It's in the 'napkin doodles' phase right now. Nothing too serious.


Use the exhaust like a jet venturi to help with airflow movement. I like that it is vertical : heat rises so that will help. You may need to silence the intake airflow, as a LOT of noise can come from the intake.


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## Geek999 (Jul 9, 2013)

I had a conversation with the folks who supplied my generator about quieting the thing down. They said I could put something around it, but it should be at least 3 feet away on all sides for airflow.


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## LincTex (Apr 1, 2011)

Geek999 said:


> I had a conversation with the folks who supplied my generator about quieting the thing down. They said I could put something around it, but it should be at least 3 feet away on all sides for airflow.


The 3-foot-rule comes from the NFPA book. I honestly don't think it's necessary if the right materials are used. I'll bet an enclosure made from cement/Hardie board wouldn't resonate/vibrate much, but the noise will still come from the air vents.


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