I have no trouble with a short time power out keeping my generator safe but I'm not sure how to really 'stealth out' a sound that loud, especially with the exhaust needing to be vented...
Any good methods out there?
It is a really good question and one that has never been researched sufficiently to make good easy answers available. I have spent the last 6 years researching quieting small gas powered generators (10kw or less). I have looked at the techniques used on both marine and industrial applications. I have also looked at the studies done in countries like India where small gas powered generators are a fact of daily life. The answer is there is no good cheap way to make a small generator quiet. With that said there are some things you can do to reduce the noise and depending on the amount of work you are willing to do, money you are willing to spend, and space you have you can make them close to silent.
So here is a list of techniques generally sorted by effectiveness.
1. Plant the generators feet or wheels in a tray of sand at least 3 inches thick and that extends 1 foot on every side. Thicker and further out the better. (vibration and noise reflection)
2. Put the generator on a woven sisal rug or equivalent. (vibration and noise reflection) [this was about the same as # 1]
3. Replace or extend the muffler using either a better muffler or a car muffler on a flex hose. (what I used to use)
4. Dig a hole and place the generator in the hole (some campers use this one)
5. Stick the generator in a shed and pipe the exhaust outside using a car muffler and flex pipe (great video of this on the I-net)
5. Buy a used marine genset and plumb water and the marine muffler and a water pump into the system. (still have one of these)
6. Build a soundproof shed and used a powered exhaust fan and chimney to pull the exhaust up and out of the shed directly upward. (what I currently use)
7. Build an underground bunker for your generator and used a powered exhaust that vents through water into another bunker and then naturally vents to the air some point away from your location. (what I want)
Obviously there are lots of variations and combination of all of the above and there are added dangers and complexities with each solution. Good luck and if you come up with another different direction let me know as I would love to hear about it.