On Sun, 06 Nov 2005 03:11:06 GMT, "Asimov"
wrote:

Speaking of experimenting, how about making an enclosure out of a
semi-rigid shell perhaps 1/4" thick (aluminium alloy?) but lined on
the inside with sonopan glued to its inner surface? It would lose some
efficiency but it could then be much lighter weight. I've seen a
similar sandwich construction used in quieting ventilation baffles for
mainframe computers so it isn't a new idea.

That's similar to Aerolam/bitumen idea except that the Aerolam is
lighter but stiffer for any given thickness and its lightness makes
the damping layer work more effectively.

Kal