The noise of the generator is measured in Decibels at a distance of 21 feet (or 7 meters). Decibels are logarithmic, so the difference between 50 and 60 is much more to the human ear  than the difference

between 100 and 110.



A Comparison of Sound Pressure Level and Sound Pressure

To understand a little more abour decibels click here.

Generally, the air cooled generators fall between 62  and 69 db at 21 feet. The liquid cooled are quieter, generally between 58 and 62db. The speed of the engine also determins how noisy they are. The 1800 RPM generators are very quiet.