[JRTJH]

Depending on the type of generator you have, running it in the bed of a truck may cause some pretty upset neighbors. Truck beds are like a megaphone, a little noise echos around in the bed and when it finally leaves, it's amplified a bunch. The generator that runs at 58dB may well measure 68dB or even more if it's sitting in a "steel box" with the muffler's exhaust pointed at the bed (sort of like banging a drum).

Try your setup, see if it's noisier than when operating in the open. Mine is significantly quieter out of the truck bed.