I went back and double checked my test, 10ft from genie, compartment closed, no load, only 70db not 74db.
The Onan quiet series 4000watt is advertised as 68db(A) @ 10ft @ 1/2 load.
So close enough for me, even when genie is off and no close sound source the ambient noise a mile from the highway in the country is still 64-66db.
We'll have to see if OP comes back with any numbers to quantify very, very noisy
Interesting though the generator literature states National Park Service sound level requirements of 60db(A) @ 50ft...wind makes more noise than that
, don't know how many portable genies could come meet that standard.