Those little Harbor Freight two-cycle generators are SCREAMERS! It's a little like running around the campground with a chain saw.
If you'd like a little taste of how it sounds, I believe there is a YouTube video of somebody testing one.
It IS possible to build a plywood box to quiet down a loud generator, but it's really involved, and involves sound-board, baffles, large box fans, external mufflers, and temperature-monitoring equipment.
I've done it for our Coleman 5000-watt open-frame gen-set, and it does the job well, but it takes time to assemble and take down every time you move. The pieces also take up storage room when not in use. I have been told that my gen-set is as quiet as a Honda 1000, but that might be stretching it just a bit.
However, the up-side is that we can run A/C, microwave, and re-charge the batteries, all at the same time.
We last used it at a Bluegrass festival, where evening campground noise is discouraged, except, of course, for the musical "jammers".
Usually I leave it all at home, and dry-camp.
Here's a shot of it, but not shown are additional baffles that prevent noise from getting through the fan.