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Subject: Re: Any ideas on measuring radiation in the home ?
X-Newsreader: Microsoft Outlook Express 5.00.2919.6700
Date: Fri, 11 Oct 2002 00:40:08 GMT
NNTP-Posting-Date: Fri, 11 Oct 2002 00:40:08 GMT
Organization: AT&T Worldnet
"milne_v" wrote in message
> "News2020" wrote in message
> > There are even more sources of noise in a small urban neighborhood.
> > Last night I found three more sources of 'weird' sounds and some other
> > sources of loud sounds at night.
> > One was a slow repeating bubbling sequence at midnight; one might
> > to be a washing machine cycling slowly; it was quite loud enough to
> > sleep. I went outside to check. The neighbor at the far end had his
> > left open. The noise was coming from inside, getting reflected from the
> > opposite building and reaching my house almost without loss of strength.
> > Initially I thought it must be the washing machine inside. But, on
> > inspection, I found that it was not. It was coming from the water-heater
> > area nearby. Possibly a hidden speaker set/transducer there ?
> > Another was the new lighting outside the garage doors. Most of the old
> > small bulbs have been replaced with compact coiled (antenna like)
> > flourescent tubes. One of them was giving out a directional high-pitched
> > audio tone pointed down the road.
> > Even a community street light (yellow) (or its lamp post ?) was emitting
> > strong tone.
> > Area utility transformers seemed to be emitting a buzz that could be
> > 10 - 20 ft away - that was not too loud.
> > Passing cars and trucks are significant sources of noise at night ! They
> > very loud. I found that garbage trucks are an order of magnitude louder
> > even that. Those trucks have something wrong with their construction.
> > One interesting difference I noticed between last night and the night
> > was the total lack of background noise. The night before I had heard a
> > very loud background roar that I assumed was due to 'freeway traffic' -
> > mile away. Last night that noise was completely missing ! I think this
> > new source of noise that is yet to be identified. It is probably
> > originating from the airport area (farther away) and not at all traffic
> > noise from the freeway ! It is hard to imagine heavy traffic at night
> > freeway that would be needed to create such loud noise.
> > Noise reduction/elimination must be made part of every design.
> > homes, neighborhoods, even aircraft. < Passing aircraft completely
> > the whole area with noise of all kinds of frequencies ! >
> > I believe this is achievable with today's technologies.
> What is HSS?
> HyperSonic Sound Technology is simply the most revolutionary sound
> reproduction system of this century. Not since the development of the
> "cone" loudspeaker more than 75 years ago has any technology provided
> such significant departure from conventional loudspeakers and such a
> remarkable new approach to the reproduction of sound.
> The directivity (narrowness) of any wave producing source depends on
> the size of the source, compared to the wavelengths it generates.
> Audible sound has wavelengths ranging from a few inches to several
> feet, and because these wavelengths are comparable to the size of most
> loudspeakers, sound generally propagates omnidirectionally. Only by
> creating a sound source much larger than the wavelengths it's
> producing can a narrow beam be created.
> Clearly, having loudspeakers twenty metres wide is not very useful.
> therefore ...
> to make a narrow beam of sound from a small acoustic source, we
> instead generate only ultrasound.
> The ultrasound, whose wavelengths are only a few millimetres long, are
> much smaller than the source, and consequently travel in an extremely
> narrow beam.
Thanks for the post.
The author of the paper does describe it fairly well with history and
mechanical detail as well.
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