# How can I sound-proof my generator?

Looking for advice to semi-soundproof my extremely noisy gas generator, which kept everybody edgy on Field Day. It's a real powerhouse, but the cost of that power is my hearing. I'm looking to buy or homebrew something lightweight that I can use to enclose the generator, but leave easy access to refilling the tank, exhaust, etc. Thoughts? Links?

It's a Champion 100155 : https://www.championpowerequipment.com/product/100155-7000-watt-dual-fuel-generator/

## 2 Answers

I'd argue that power law is your friend: It's probably cheapest and most reliable and least of a hazard to get a long cable and place the generator as far away as feasible, possibly behind a car, rock, very large dog, small elephant, large elephant…

Downside of long cables of course is voltage drop due to resistance in the cable. Rule of thumb: The longer the cable, the more copper crosssection would be sensible. Before you spend lots of money on oversized cables: You can find the AWG table on every corner on the internet, and they list resistance per length for any common conductor diameter.

Calculate your maximum current drawn (if using many inductive / bad-PFC devices, 1.4× that number), approach with "I can live with a voltage drop of $x\in[2\ldots20]\,\text V$ for that current", calculate maximum resistance that would allow that ($U=R\cdot I$), and then just pick a cable diameter that doesn't have more over the length of cable you want to use.

Other than that, speaking from experience with a small car with a holey muffler: Probably, the exhaust end of the engine is where most noise happens. If you have a garage of your trust, maybe ask them whether it's realistic to add a muffler without losing too much power?

• Great advice, Marcus. However, the longer the cable the larger the conductors need to be. (But I know that you knew that. ;-) Maybe you can edit this answer and add details. – Mike Waters Nov 9 '17 at 22:50
• I have a Honda EX650 which is known for being relatively quiet; key to that is its muffler. retrofitting a better muffler is not too difficult; I recommend buying one intended for a larger engine and adapting it to fit your Champion. – niels nielsen Nov 10 '17 at 1:02
• I do like the muffler idea. I have a friend who's a mechanic, so lemme ask him. Thanks and 73 – Noji Nov 11 '17 at 2:29

Distance is great (except the line loss). Mufflers COULD be good if designed and installed correctly. You can even go so far as to install more than one muffler in parallel. Making the other (not the exhaust) noise quieter will take an enclosure. You could make an enclosure with a lid or extend the fuel fill opening above the enclosure. A simple box with sound dampening material (lots of things will do) on the inside will probably help. It would be nice if there is a window so that you can see the meters and controls. Be sure to check the oil level too!

• I have some leftover carpet remnants. You think those might work, say, attached to some thin sheets of plywood, etc? – Noji Nov 15 '17 at 23:51
• Yes, carpet is usually a good sound insulator. Just keep in mind the other things I mentioned, access to fuel, oil, and gages. – Keith Martineau Nov 29 '17 at 3:25
• Also don't forget to allow air into the engine, exhaust to exit the enclosure, and adequate distance from hot engine parts to your enclosure. – Keith Martineau Nov 29 '17 at 5:43