On Oct 11, 7:46 pm, Larry Dighera wrote:
On Thu, 11 Oct 2007 15:57:17 -0700, daffy
wrote in . com:

Quite a good article in the Nov/Dec AARP magazine titled "Listening
for Quiet".
It talks about a silent sanctuary in Washington's Olympic National
park. The article
concluded by someone complaining about the silence broken by a small
plane.

The article said "The small plane flying north more than doubles the
ambient sound,
and we react to the intruder as a threat, drawing in, tracking the
source, hunching for
cover until the last traces of engine noise finally die away."

Did the article happen to mention the duration (in seconds) that the
noise from this "intruder" was detectable? There is little question
that small airplanes are noisy, but they are usually only audible for
about 20 seconds. In the area in question, it may be longer, but the
sonic impact of the occasional lone aircraft is nothing compared
living adjacent to a busy street. Perhaps we should consider closing
all the roads in residential neighborhoods. :-)

I live directly below the traffic pattern of a busy GA airport in
Dayton, and there are four airports closeby. I am sensitive to noise,
and I go to great lengths to keep my environment noise-free. I have
noticed that the airplane noise is nowhere close to the noise from all
the lawnmowers that seem to constantly run from April to October.
Airplane noise lasts about 30 seconds. A lawn mower runs for an hour
or two. Sometime the noise never ceases as each neighbor fires up
their lawnmower in turns. It would be interesting to do a measurement
and identify the average contribution from all the noise souces. With
a digital recorder and some signal processing software this ought to
be doable. One also has to consider the impact of noise on the human
ear. Widely varying pitch is worse than a constant dull hum. A
chainsaw noise is worse because of all the "vroom vroom" accelerations
and decelerations.