On Fri, 21 Jan 2005 10:31:28 -0800, "Roger Shoaf"
wrote:

Sure it will be a little better, but only a little bit. The thin stuff will
reduce the noise to near zero. The thicker stuff might be available in
smaller quantities however so that might be it's biggest point.

I would expect it to be noticably better. If the lead acts as the
mass in a second-order system, 2.5X the mass per unit area should drop
the corner frequency by 2.5 x or 1.32 octaves. At a given frequency
above the corner freq, at 20 dB/octave that's 26.4 dB more
attenuation. The biggest issue will probably then be muffling the
air passage.

Since a genny runs at essentially constant speed, the air vent could
greatly benefit from tuned resonators, at least at higher freqs. A
heroic solution might be forced-air (a blower) moving air thru the
enclosure, with automotive mufflers on inlet and outlet.