Help Needed to Reduce Installed Generator Noise

I think I'll first try to install a new floor on the storage compartment floor including absorbent material plus a layer of plywood, That will be the easiest to do. It should stiffen the layer just above the generator and should reduce some of the noise propagation from below. Since the generator is supported from this floor structure, I suspect most of the vibration noise is transmitted from that surface. Thanks to DrewE and all for the suggestions.