My favorite generator is our little Honda EX650 four-stroke that we use for battery charging in our RV. It is only one dB louder (54dB) at it's constant fixed speed than a Honda 1000i is at it's idle speed (53dB). It'll run about 5 hours on 0.6 gallons of fuel.
The EX650 sound is also different than that of a 1000i. The EX650 is a low-pitched humming sound with no mechanical parts to it, while the 1000i has some mechanical sounding noises.
I also have a Honda EX1000 in the shop for power tools, a 4000W two-speed genny on wheels for residence power outages, and a 4000W Onan built into the RV. The Onan is fairly quiet and vibration-free and can be used for hours without irritating us when drycamping.