Re: Engine thrust noise at GLR

On Jan 8, 2:06�am, Hiram <deerhunter...@gmail.com> wrote:

On 08/01/2010 07:01, Lumpy wrote:

I live in the suburbs of Phoenix.
At night, when there's no traffic on the roads,
I can hear the fire station doors opening and the
trucks starting. They are right at 3/4 mile away
from me.

Any time of the day, I can hear the F-16/F-15s
landing and esp taking off at KSDL which is
three miles away. They refuel there on weekends
when the Air Force is closed. That noise is loud
enough to make it hard to talk on the phone, not
just faint and "hear it if you listen hard enough".
And that's talking on the phone inside the house.
My house is concrete block construction.

I can hear horses and burros at least three miles
away in our subdivision.

My hearing is horrible. I have a lot of high
freq loss in both ears, and extremely bad in
my right ear.

So for people with good ears, in an area with
very little ambient noise, I would certainly
expect something as monsterous as a jet engine
to carry many, many miles indeed.

Craig 'Lumpy' Lemke

www.n0eq.com


Doesn't sound travel further when its cold?


The speed of sound has a temperature component to it. [There all all
sorts of patents for acoustic thermometers.] I don't know about it
going further. If you have cloud cover, that will reflect sound.

The thing with the winter is the surroundings are more sound
absorbent. With snow, this is really true, but anything that makes the
surface softer helps to absorb sound. [Think of sound absorption is
the inverse of being aerodynamic. That is, you really want drag,
friction,etc so that sound gets converted to heat.] Now all the sound
is getting this same treatment, including what you want to hear, but I
think the reduction in ambient noise is the key.

I was at that "desert overlook" on Mt. Charleston  in the winter. I
could hear the rock fracturing and falling to the ground.