I run my small chemical company off the grid using a diesel generator for most of my power. Right now, I'm using a 6kw light plant with a Mitsubishi 3 cyl diesel. It isn't too loud. I have a 12kw Changfa clone that runs great but is so loud that I've been waiting to put it into service until I could do some work on sound deadening. Here are some ideas I've gleaned from here and elsewhere:
Mount the generator on a trailer- Use the tires as an insulator for the low end "thumps". Or make a sand bed to place the genset on. The idea is to isolate the generator from the surrounding ground.
Build a doghouse around the generator- This is my ultimate plan. I want to relocate the radiator outside this box. I can get some insulated panels like they use in making walk-in freezers. These panels are 24" or 30" wide, 3" or so thick, sheet metal on exteriors with "styrofoam" in the middle. With a solid surface on the interior, I wonder how much it will drop the sound. Sound rooms (for hearing exams) usually have perforated wall panels. Would a solid metal interior wall just create an echo chamber? At minimum, I'll use some of the foam insulating panels from Home Depot. They have 1/2", 3/4" and 1".
Run a larger diameter exhaust and have it pass through a drum of sand- I've heard of folks running the exhaust in a drum of gravel buried in the ground. Do they have the pipe run through the gravel or does it just exhaust into the ground? Before doing anything, I'm going to check the exhaust back pressure. I've read that 1.5psi at idle and no more than 3psi at 2000rpm is a target.
Change the intake system- I've ordered a plastic air intake housing. It looks like what is on a Kubota diesel air compressor I have. This air cleaner is designed for a much larger engine than my Changfa so I'm hoping it will give more room for the pulsation of the air.
Recently, I ran across a paintable/sprayable coating from the manufacturer of undercoating material. This sounds promising. What about applying it to the valve cover, engine cases, etc? With water cooling, it shouldn't cause the engine to run hotter, should it? I would add an oil temp gauge, adding an external oil cooler if necessary.
Other ideas? Warnings?