Not Measured by Manufacturer - Why Some Generators Don't List Decibel Ratings
Why Some Manufacturers Don't Measure Decibels
"Everyone hears differently, and although a generator may list its decibel rating, its sound will still vary from person to person depending on the location of the generator and where the person is standing.
Therefore, decibel ratings aren't always as accurate as they were intended to be, which is why many companies are hesitant to provide any at all. The location of the generator, the direction in which the exhaust is pointing, and the type of generator you have all influence the noise level."
not my words above, but makes sense to me... although it does make it hard to compare...