Hearing Protectors

[Don]

Hi,

Jim if you add -2 and +2 the result is zero. Cancellation devices do just
that--BUT and this is a big but--only at selected frequencies (usually
quite low frequencies i.e 1500 hertz and below). They also at the moment
are limited to a drop of say 15 db.


At 10:27 PM 10/16/98 EDT, you wrote:
>
>In a message dated 10/16/98 6:16:07 PM, nhunt@jagat.com wrote:
>
><<". . A harmful noise level without use of a noise canceling device is
>just as harmful with the use of one."
>
>Jim, this is not true.">>
>
>Newton;
> As calmly as I can I must insist that it is.  The devices we are speaking of
>are noise 'cancelling' devices and not a form of hearing 'protection'. What
>these jewels do is remove a perceptible noise and  keep the noise, i.e. sound
>waves, from 'perceptibly' reaching the eardrum. They work by creating a
>reverse, or mirror image, of the sound frequency (ies) you want to attenuate
>as perceived or audible sound. They do nothing about keeping these sound
>waves, both of them, from reaching your eardrum.
> If these dillys worked for 'protection' as well as they work for
>'cancellation' they would be mass marketed with a zeal and perspicacity the
>likes of which have yet to be seen.
>Jim Bryant (FL)
>
>
>
Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T.
"Tuner for the Centre of the Arts"
drose@dlcwest.com
http://www.dlcwest.com/~drose/
3004 Grant Rd.
REGINA, SK
S4S 5G7
306-352-3620 or 1-888-29t-uner