Re: Engine thrust noise at GLR

On Jan 7, 1:48�pm, "NC" <N...@invalid.com> wrote:

"Desert Shadow" <rch49...@cox.net> wrote in message

news:cc54b6aa-25dc-4fb7-b597-71c00f8bdd60@s31g2000yqs.googlegroups.com...

I ran out to the perimeter of Area 51 just to see what was going on.
Usually there is not much action on our side. Now the interesting
part, we both heard this strange noise. I have been to the GLR warning
signs at least 40-45 times and never heard anything like this before.
It sounded like a rumble just past the first set of hills. I thought
it sounded like a hot air balloon when they pull the cord to fill it.
It sounded like engine thrusting but there was nothing in the sky. It
would last 12-15 seconds at a burst and then stop suddenly. This
happened at least 3-4 times. Is it possible to hear engine thrust
testing from Groom at the GLR warning signs. To me it seems way too
far. I was able to capture this sound twice on my digital camera. The
video quality sucks! The loudest sound is my camera. If you
concentrate on the background sound you will hear the rumble. It was
quite noticible at the GLR. Everybody heard it and questioned what it
was. If you watch the two videos a few times you can hear the sound.
Any thoughts???

Video 1
http://www.youtube.com/watch?v=eeS5QmESmkw

Video 2
http://www.youtube.com/watch?v=8Udvostg6ew


Thrust noise can travel 20 miles or more. Especially at night. But that is
over flat country here in Florida. Folks in Jupiter can hear Pratt & Whitney
testing that is 20 miles out in the swamp.


And the desert can be extremely quiet. The one time I drove down to
the front gate with snow on the ground, it was so quiet I could hear
their radios crackling. Kind of like the first edition of Half Life
when you have to battle the camo dudes.

Somewhere around 1998 or 1999, I was at the foxtrot 4 gate near Cedar
Pass and heard engine testing. Unknown if it was the TTR or Groom
Lake, but probably TTR.

I was at the F4 crash near Rachel once when it was unbelievably quiet.
The guy I brought there swore he could hear the blood pumping in his
head. I didn't sense that, but I know people who have been in anechoic
chambers that they get that sensation.

I've done recordings when I think I hear distant jet noise using my
Zoom H2 recorder. You really need a directional microphone for this
application. I searched this a while ago and concluded a certain
Sennsheiser microphone is best for this work. (I can dig up the model
number if anyone is really interested.) It is a matter of the
microphone being both directional and itself very quiet. But you
really don't need the ultimate set up. I've used an Audio Technica
shotgun and it's very effective. There are also some Rode microphones
that are very quiet and similarly priced to AT.