Sonic Devices

Hello folks,

I've just noticed a new device due to be on sale in the UK soon, it's called
the 'soundbug' and attaches to any surface (including the human skull) and
turns it into a sounding board.

I'm interested in the possible utility or weaponry applications of such a
device (connected to an appropriate tone generator and amplifier). How much
output might be required to break toughened glass, or the plexi of riot
shields
etc..

The device is fairly cheap (and probably simpler to make something along the
same lines yourself).

It might be interesting to run a SG2 riot game where some of the rioters who
get into close combat with the police could shatter shields and other
equipment.

What might you do to protect something against such an attack?

For your information the manufacturers are Newlands Scientific

   http://www.terfenol.com/index.asp

and there is a story on BBC news about it

   http://news.bbc.co.uk/hi/english/sci/tech/newsid_1879000/1879247.stm