On Tue, 31 Oct 2017 11:18:04 +0700, John B.
wrote:

On the other hand is the alternate is a 1,000 ft drop off the side of
the mountain it has a sort of comforting sound :-)

Not to worry. NASA is working on a solution:
https://www.nasa.gov/sites/default/files/thumbnails/image/ed15-0373-32.jpg

"Jake brake contest 2014 (Full)"
https://www.youtube.com/watch?v=pHTrEwRk0MU

The winner delivered about 130dB SPL which is what a jet taking off
produces at 100 meters:
http://personal.cityu.edu.hk/~bsapplec/Fire/SPL01.jpg
http://elephanttech.com/wp-content/uploads/2013/11/decibel-levels-erar-plugs.jpg

Don't get too carried away with those decibel charts. The sound of a
jet engine at full throttle is very noticeably different depending on
where you are standing. In an engine test cell where you can walk
around the running engine standing a distance in front of the engine
results in very much lower sound levels then standing the same
distance behind the engine.

Yep. The noise is somewhat proportional to the change in air
velocity. The exhaust velocity is much higher than the intake.
I have no idea which end of the engine the 133 dB SPL refers to.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558