Arne wrote:It would be interesting to try a circular foam wall around a noisy generator... the foam would block the direct noise, and absorb some, and direct the rest upward... It would be easy to roll up and carry.. well, not THAT easy, but doable....
A similar effect would be to put the generator in a depression in the ground (and hope it doesn't rain). When I'd run my nitro powered r/c monster truck, it was so much quieter when driving down in a ditch. I still had line of sight but it was so much quieter, because most of the sound was directed upwards and not reflected on everything else.