Listen to This!
By Will Craig
Those ubiquitous white cords that snake up to the ears of returning students
this fall should remind us of the effects and necessary remedies of prolonged
exposure to high volume sound. While OSHA rates permissible noise exposure for
8 hours as high as 90 dB, many experts favor an 85 dB cap on long-term noise.
And, let’s face it, nobody plays their music at what audiologists view
as a safe level. No wonder a recent Newsweek article (May 2005) cited a study
that estimates as many as 5.2 million students in the United States have hearing
damage from prolonged exposure to loud sounds.
The Americans with Disabilities Act (ADA) requires lecture halls and other
rooms “where audible communications are integral to the use of the space”
with fixed seating that seat 50 or more _OR_ have an audio amplification system
be equipped with a permanently installed assistive listening system. Such a
system may utilize infra-red, induction loop, or radio frequency broadcasts,
but the number of receivers must equal or exceed four percent (4%) of the total
seats, with a minimum of two (2).
Several of my recent experiences with assistive listening systems may be instructive:
Have somebody else try it before you buy it.
Demonstrations of assisted listening equipment frequently consist of putting
earphones on people with normal hearing (usually the people involved in making
an acquisition decision) and playing music and spoken word content to them through
a wireless system. Aside from technical glitches, I’ve never heard much
difference between different manufacturer’s systems--sure, there are small
differences in the amount of background noise, or in frequency response--but
even with back-to-back listening through different systems, they’re hard
to differentiate.
I recently conducted an evaluation of assistive listening systems in conjunction
with the State of Minnesota Department of Human Services’ Deaf and Hard
of Hearing Division. We invited several leading assistive listening manufacturers
to bring their best products, and had evaluators on-hand with a broad range
of hearing losses, from mild to profound. Not only could the evaluators discern
important differences between the systems, they found that one particular manufacturer’s
equipment, which sounds great to listeners with normal hearing, was completely
unacceptable due to lack of available gain/volume. Just because it sounds fine
to the person in the purchasing office d'esn’t mean it will work for students
(or faculty) with hearing loss.
Density makes a difference.
On a recent project, we were specifying a large number of systems for proximate
rooms (a common situation in campus buildings with large numbers of classrooms
and lecture halls). The users requested FM-based assistive listening systems,
with neck loop option for T-coil users and headphones for everyone else. Most
standard FM assistive listening systems have 10 wide-band channels. When there
are more than 10 rooms in close proximity and cross-over interference is possible,
FM system users must move to narrow-band receivers (many standard transmitters
can broadcast wideband or narrowband). The construction and composition of the
walls, as well as any need for privacy, can also drive whether FM (wideband
or narrowband) is an appropriate solution. This requires up-front planning and
careful specifying to ensure that the units delivered will be compatible with
each other and that users in nearby rooms are not adversely affected.
4% and a sign – enough?
A pre-design report for the renovation of a major University’s 500-seat
auditorium called for providing two (2) assistive listening receivers. Some
may object to buying 20 receivers for this type of room, saying that receivers
are rarely (if ever) requested. Assistive listening is something that people
have to want to use, and, they have to ask for help in order to get it. The
ADA requires that an approved sign be posted wherever assistive listening systems
are available, but who are students going to ask to get the receivers from?
Who is going to make sure that the batteries are charged between classes? There
are a number of details to be worked out in making an assistive listening solution
workable--otherwise, the equipment sits on a shelf in the back room, collecting
dust.
Hopefully these thoughts will be useful for those seeking ways to make classrooms
accessible to all students. Please contact me with your thoughts and/or experiences
on assistive listening systems.
Will Craig d'esn’t own an iPod but d'es play his car stereo too loud on
his way to work as a consultant for Elert & Associates, a multi-disciplinary
technology consulting firm based in Stillwater, MN.
