Assistive Listening Systems for People who are Hard of Hearing
Assistive Listening Systems (ALS) and/or Assistive Listening Devices (ALD) are any technology developed to enhance the abilities of a person who is hard of hearing, to better hear and understand public presentations. These systems can be used with a television set, in small gatherings, in class or meeting rooms, and in venues like auditoriums and theatres.
What do they do?
ALS's and ALD's amplify sound. Because these systems and devices frequently tap directly into the source of the sound by using a microphone clipped to the speaker or suspended above a stage, they help to clarify sound by cutting down or eliminating ambient noise. But, primarily the job of the ALS or ALD is to make the source sound louder and give volume control to the individual.
Who uses Assistive Listening Systems?
America has an estimated 32.5 million adults who are deaf or hard of hearing. Of these, 19 million have some residual hearing that enables them to benefit from the use of assistive listening systems. 15 million people who can benefit from the use of an ALS do not use hearing aids and 4 million use hearing aids. *Source: Summary Health Statistics for U.S. Adults, National Health Interview Survey, 2003, tables 11, 12, 18 and 19.
How do Assistive Listening Systems Work?
There are two primary modes of transmitting sound: via radio waves and via infrared waves. There are basically four types of systems which all include a microphone, transmitter, receiver and headset. The mixer/amplifier and transmitter are frequently one unit.
The hardwire system is a closed system, meaning the sound is never broadcast outside of the cables. This is the type of system used in airplanes where the headset is plugged directly into the jack at your seat.
The induction loop system broadcasts via radio waves within an area encompassed by a big directional antenna. To get amplification the individual must be seated within the area the antenna circles.
The FM system operates just like a small radio station with pre-set frequencies, that the FCC has determined and restricted for use by assistive listening systems.
The infrared system is known as a "line of sight" system since the receiver must be in line of sight of the emitter because infrared waves will not go through a solid object.
Four Basic Systems: infrared, FM, loop, hardwire
Types of Headsets: over the head, under the neck, monaural, binaural, induction loop
Types of Receivers: two types of receivers
Visit the Kennedy Center's Accessibility Resource for more information on Assistive Listening Devices.
Directory of Manufacturers and Vendors
The following is a list of manufacturers and/or suppliers who carry assistive listening systems that are used in facilities and venues like classrooms or theaters. This is not a comprehensive list nor does inclusion on this list imply any kind of an endorsement of the company or product.
Call the manufacturer or supplier and find a vendor in your area who can sell, install, and help you maintain your equipment. Some manufacturers will sell directly to the public and some will not. (M=Manufacturer, S=Supplier)
All Systems
Audio Enhancement (S)
9858 South Audio Drive
West Jordan, UT 84081
(800) 383-9362
audioenhancement.com
Centrum Sound (S)
2384 Voltaire Way
Redding, CA 96003 USA
(888) 736-6005
www.centrumsound.com
Clearone Communications Corporation (M)
5225 Wiley Post Way, Suite 500
Salt Lake City, UT 84116
(801) 975-7200
www.clearone.com
FM and Infrared Systems Only
Listen Technologies Corporation (M)
14912 Heritage Crest Way
Bluffdale, UT 84065-4818
(800) 330-0891 Toll Free
(801) 233-8992
www.listentech.com
NADY Systems Inc. (M)
1260 Humbracht Cir
Bartlett, IL 60103
(630) 233-1521
www.nady.com
Sennheiser Electronic Corp. (M)
Germany
(877) 736-6434
www.sennheiser.com/en-us
Williams Sound (M)
10300 Valley View Road
Eden Prairie, MN 55344
(800) 328-6190
www.williamssound.com
Infrared Systems Only
ALDS, Distributing Inc. (M)
Langley, B.C., Canada V3A-7A3
(604) 533-9884
(866) 845-2537
www.alds.com
Audex (M)
PO Box 3322
Kilgore, TX 75663
(903) 987-1199
www.audex.com
Lightspeed Technologies
11509 SW Herman Road
Tualatin, OR 97062
(800) 732-8999
www.lightspeed-tek.com
Induction Loop
Oval Window Audio (M)
33 Wildflower Court
Nederland, CO 80466
(303) 447-3607 Voice/TTY/Fax
www.ovalwindowaudio.com
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