Construction material for portable generator sound-deadening box

[CurlyDave]

IMHO you will be far better off to just buy one of the ultra quiet generators. They are pricey, but they work.

Unless you are an engineer, running a generator inside any kind of home-made noise suppression device will bring you grief and danger. If these were easy to make, they would be on the market.

I am an engineer, and my solution was a Honda eu2000.

 

[joshuabardwell]

I will never box a generator again. I would rather listen to it than risk what could have happened that day.

I appreciate the feedback, and I definitely plan to do thorough testing to ensure adequate cooling before using the box unattended. I plan to use an IR thermometer to measure temperature at various points during normal running, and then when in the box. I'll probably also install a 120v pancake fan, since there'll be a ready source of 120v power when the genny is running.

All that being said, the real question I have is: did the blue insulation board work to quiet the generator?!

 

[joshuabardwell]

IMHO you will be far better off to just buy one of the ultra quiet generators. They are pricey, but they work. Unless you are an engineer, running a generator inside any kind of home-made noise suppression device will bring you grief and danger. If these were easy to make, they would be on the market. I am an engineer, and my solution was a Honda eu2000.

No way that the quiet is worth the price of an eu2000 to me. If the box doesn't work, I'll just suck up the noise.

 

[forgeblast]

I have bought foam kits through Foam it green .com . I am wondering if you need to make a box but what if you went with something that looks like a dug out (3 sides sloping roof) to bounce the sound away from you.

 

[MarkV]

Would a better muffler on the generator be an option? Mine is also crazy loud and have thought of after market mufflers, I just don't use it enough to bother.

MarkV

 

[dmccarty]

One way to minimize sound transfer is to disconnect one side of the wall from the other side by offsetting the 2x studs. A picture is worth a gazillion words, look at the bottom of this page, How to Soundproof a Wall

You use two sets of 2x studs, one set for each side of the wall. Wall covering is attached to only one set a of studs so there is no direct sound transmission through the wall. Insulation is added for more sound deadening. I thought about doing this for interior walls in our house but figured it was overkill. I think we have more sound transfer through the slab than the walls.

These types of walls are insulated to cut down the noise but that is also going to cause a build up of heat. Not sure how to safely deal with the heat issues. Then there is that pesky exhaust and air supply to worry about.

The huge generators at work sit in metal inclosures on a side of the building sorta away from people. When those gensets are started, they make a heck of a racket.

Later,
Dan

 

[s219]

A great sound insulator is fiberglass batting behind perforated metal or perforated masonite peg board. The holes really knock down mid and higher frequency noise and the fiberglass damps the rest.

A good rule of thumb is that you want the absorber to be about the size of the wavelength of sound you're trying to attenuate. So low frequencies (deep noises) need big structures, while high frequencies need small structures.

The most effective way to quiet the generator would be to figure out what noises it's putting out, and then target the most annoying ones first. But that takes a sound meter, which is not a typical piece of equipment for most of us. I'd probably experiment and see what works best.

 

[3930dave]

Coupla thoughts...

Just had the doghouse off my van. Full size vans aren't popular anymore, but maybe some of the Michigan guys who hang out here know who can supply the doghouse insulation. Appears to be some type of fibre, covered with heavy "tinfoil".

As discussed, the thermal engineering is non-trivial. Consider investing in some thermocouples - they aren't that expensive. Fluke used to sell a thermocouple adapter (essentially just a calibrated amplifier) so they will direct read Temperature on a DMM. With a good DMM, you can direct read the Tcouple output, look up a table, and convert to Temperature - PITA though vs. the cost of an adapter.

Sensors, Thermocouple, PLC, Operator Interface, Data Acquisition, Rtd is one source for Thermocouples, Fluke too.

External fuel tanks, at least during testing, should help on the safety front.

Did some research a while back.... the best bang/buck muffler implementation I saw was using a 600cc street bike muffler. (600s being the sweet spot in the street world, lots of guys drive the bike home from the dealer and pull the stock exhaust. Ergo, lots of virtually unused 600cc mufflers are for sale, and therefore cheap).

The example I saw was on a Yamaha genny, that a guy built to run at Glammis. Essentially built a tripod, and had the bike muffler firing straight up. Good solution, low cost, and mostly comes down to having some intermediate metal working skills.

Pls keep us posted how this goes.

Rgds, D.

 

[buickanddeere]

Obtain a quieter generator and a longer extension cord.
A acoustical baffle only needs one side and a top. Find the foam with the points and pits. Probably on eBay.
As previously stated. Heat is everything

 

[joshuabardwell]

I have bought foam kits through Foam it green .com . I am wondering if you need to make a box but what if you went with something that looks like a dug out (3 sides sloping roof) to bounce the sound away from you.

I am thinking that direction too. Simply redirecting the sound, vs. enclosing the genny entirely, would help with the air flow and heat issues.

Would a better muffler on the generator be an option? Mine is also crazy loud and have thought of after market mufflers, I just don't use it enough to bother.

From what I have read, putting a muffler on a generator isn't much worth the trouble, because so much of the generator's noise is from the motor itself, not the exhaust.