Joe wrote:
> It might be difficult but it's not impossible. They're using systems
> like that on US Army tanks right now.
[snip]
Not to mention the active nose cancellation headsets that I and most
of my friends were while flying. They're designed only to deal with
low frequency noise; when you turn them on it's like someone stuffed
high-pass cotton into your ears. Voices sound perfectly normal but
the drone of the engine sounds like it's in the next county.
The big problem is power density -- these things only have to provide
cancellation in the confines of a headset ear cup. Cancellation in the
large would obviously require much higher power levels.
I remember when I first heard about something like this, back in the
mid-to-late 70's. Some grad student at MIT was working on something
he called "the noise sucker", but I don't recall the details.
--
Chris Kennedy
chris_at_mainecoon.com
http://www.mainecoon.com
PGP fingerprint: 4E99 10B6 7253 B048 6685 6CBC 55E1 20A3 108D AB97
Received on Thu Jun 21 2001 - 18:52:35 BST