From: Jonathan Spencer, [EMAIL PROTECTED]
In an earlier post, I said:
>I have measured the sound pressure levels of
>all of these (the BP 'rifle' was a riot gun firing CS and plastic baton
>ammo) and the pressure curves of HV rifles exceed everything else.
and [EMAIL PROTECTED]
>It wasn't so much the sound pressure level as the frequency curves. The
>Noisebreakers have a baffle system that lets some frequencies through
>better. Very high frequencies, like bird song, are hardly attenuated at
>all.
It's my understanding that it is the high frequency noise that does the
damage. I'm open to correction on this, as ever.
>I would be interested to see your results, if you have them online or
>electronic.
Here are some figures. If anyone uses these, courtesy requires you to quote
the source (Jonathan Spencer of Keith Borer Consultants). I don't have
frequency of SPL the graphs we produced.
(outdoor) (indoor) (indoor)
9mm S&W 5946 124.1 124.0
9mm GLOCK 17 128.5
H&K MP5 standing 121.9 120.1 126.0
H&K MP5 prone 122.4 126.0
S&W .38 124.3 120.4 126.0
Rem 700 7.62 kneeling 124.8
AR 180 5.56 127.1
L85A1 5.56 129.7
FN 7.62mm 130.5
Rem 870 12ga buckshot 124.4
Rem 870 12ga slug 125.8
S&W 100P 12ga 131.0
Schermuly 37mm 125.9
1�" L67 122.5
--Jonathan Spencer, firearms examiner
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