I read in sci.electronics.design that Terry Pinnell
wrote (in
) about 'PC CPU fan', on
Mon, 3 Oct 2005:

It's just resting on the carpet and underlay at the side of my desk.
Then wood flooring and plasterboard lounge ceiling below.

That's not effective sound insulation. Your wood floor will love to
vibrate at 1 Hz, even if it's not tuned to that frequency. You need a
THICK pad -- no, thicker than that!
--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk