From: "Bill Shymanski"
Subject: Re: Sound cancellation technology?
X-Newsreader: Microsoft Outlook Express 5.00.2919.6600
X-MIMEOLE: Produced By Microsoft MimeOLE V5.00.2919.6600
Date: Wed, 25 Dec 2002 21:54:07 -0600
NNTP-Posting-Date: Wed, 25 Dec 2002 21:53:49 CST
Organization: MTS Internet
OK, maybe I've got a bug in my bonnet this month. Anyway, while waiting
for an impulse test to be
set up on a large power transformer, I was reading a draft IEEE guide
covering noise suppression
techniques to be used with large power transformers. One of the methods
proposed is active
noise cancellation, which apparently gives 10 to 15 dB of suppression of
the "tonal" hum associated
with power transformers. The draft guide seems to indicate that this
technique is commercially
Other places I've read of sound cancellation being used is aboard
aircraft; some of the commuter jets
has speakers throgh the cabin to hold down the noise. Mr. Rutan used a
noise-cancelling headset during
his round-the-world flight a few years ago.
"Lady Liberty" wrote in message
> How far along has sound cancelation technology come in the last 10
> Can they use it to completely silence a bedroom area for sleeping, yet?
> BTW, does anyone still do electronics prototyping on the west side of
> Denver? I used to work in it but haven't seen any jobs for it, for years