Sound Business ... or is it ?

          SOUND BUSINESS OR IS IT?
                  By George Schank

      We usually think of noise as any unwanted sound.   Something we don't
care to listen to.   But occupational health professionals tend to define
noise in terms of an environment in which sound levels are high enough to
cause degradation and eventual degeneration of a person's ability to hear
properly.

      As we all know, sound levels are measured in units of decibels.   The
maximum steady noise in a workplace is 90 decibels.   Exposure to levels
above that number can, over time, cause permanent and irreversible
hearing damage.   Even a one-time exposure to levels in excess of  90 dB
can be enough to cause at least temporary damage to hearing.  The bones
in the inner ear are so tiny and fragile, that, once damaged, they can
never be completely repaired.   For some people,  levels well below 90 dB
can cause damage.  Once lost, the only way a person may ever hear, as
they once did, is by artifical means.

     Occupational safety and health studies have shown that noise can also
cause fatigue, irritabilty or safety-compromising distractions.   It can
also be the cause of headaches, nausea and impairment of memory and
concentration.   Any environment where normal speech cannot be carried
on, due to the amount of noise present, can cause an increase in the
number of errors in a given task.  We all remember the WKRP television
series where you see Venus Flytrap or Johnny Fever jamming with their
"cans" on and their eyes closed; seemingly lost in another dimension, and
oblivious to what's going on around them.

     There are two types of noise that can have the effects described above.
The first is noise from a source in our environment such as speakers or
motors.   The other is noise that we expose our ears to intentionally,
such as when we put on a pair of earphones.   In most of our broadcast
and sound studios, we install speakers and amplifiers capable of
generating sound levels well in excess of the allowable 90 dB level.
Even though I used to be a jock, and maybe because I was, I'm extremely
sensitive to high vloume levels in a studio.   I can't count the times
I've actually reached over and turned the monitor volume down, myself, so
that I could carry on normal conversation with an operator who wouldn't
do it himself.  

     Speakers, however, at least keep the source of the noise at some distance
from the ears of those in proximity to them.   Headphones, unfortunately,
bring the source right up to the ear; and are most responsible for the
loss of hearing experienced by many in broadcasting and sound support.

      I've flown Air Force and general aviation aircraft where noise levels
were anywhere  from 70 to 100 dB.   At those sustained levels, hearing
protection becomes mandatory for both good communication and safety.   To
perform both of these functions, we wear headphones that trap out the
surrounding noise and allow us to hear the audio material we need to hear
in order to communicate.   When I was in C-130 cargo aircraft, the crew
wore headphones, and ear plugs were issued to every passenger.   I always
felt the the earplugs had dubious value given the sustained exposure to
the noise of the aircraft; but, they were better than nothing, I guess.
I flew general aviation aircraft for many years before I started using a
headset.   Compared to the C-130, it just didn't seem necessary.   I
realized, too late, that I could have never been more mistaken.

     One advanced type of headset beginning to make it to market is known as
an Active Noise Reduction headset.   ANR headsets generally reduce the
noise level an additional 20-30 dB by electronically manipulating the
sound waves entering the ear.   The net result is a noise reduction of an
additional 40-50 dB.   Look for these type of headsets to eventually be
mandated by OSHA for anyone who has to wear headphones.   This includes
announcers, operators and engineers.   Of  course, no one will ever
mandate good sense when it comes to exposure to high noise levels.   If
you didn't practice it when you were younger, chances are the damage has
already been done.  The important thing is to take measures now, to
prevent further hearing loss by utilizing the tools available to you
today.   Hearing is a vital element of the Communications process and the
essence of our profession.   Without it you can only do your job half as
well.
                                                            George Schank

Copyright 2000 - SBE Chapter #105 - Houston - All rights reserved