ASSISTIVE LISTENING SYSTEMS
This technical assistance bulletin is one of a series prepared by the Architectural and Transportation Barriers Compliance Board (Access Board) to assist Federal agency personnel and other interested individuals and organizations to carry out the provisions of Title V of the Rehabilitation Act of 1973 (Public Law 93-112), as amended. The Access Board is authorized under section 502 of the act to provide technical assistance to persons and entities affected by regulations issued under Title V.
BACKGROUND Of America´s estimated 21 million persons with impaired hearing, approximately nine million have losses that cannot be corrected by surgery and/or hearing aids. Five to seven million are severely hearing impaired, meaning they have considerable difficulty understanding speech even with powerful hearing aids. Another two million are deaf - that is, they are unable to understand speech through the ear alone. Many individuals are aided in meetings and other large gatherings by assistive listening systems (ALS). Individual hearing aids function best in close settings when ambient noise or the noise on all sides is low. In large rooms, hearing-aid users have great difficulty hearing speakers since the aid not only amplifies the desired sound but also magnifies other sounds in the room. People with hearing impairments who do not use hearing aids often can understand speech of people near them in a quiet room, but cannot follow spoken information in larger, noisier environments. For these reasons, the nation´s four million hearing-aid users and fifteen million others who have hearing losses need some assistance from the room itself. This help can be provided through assistive listening systems which pick up sound at or close to its source, amplify it, and deliver it to the listener´s ear without extraneous sound, reverberation and distortion.
FOUR TYPES OF SYSTEMS -
There are four types of assistive listening systems that designers and managers of meeting rooms, auditoriums, and other large environments should consider. Hearing and hard of hearing listeners benefit from their use. These four ALS accept input from existing public address (PA) systems, thereby reducing cost. However, the type of microphone and its placement at the sound source is crucial for the ALS to be effective. (Example: use a condenser microphone 3" to 6" below the speaker´s chin, permitting speech-reading.) A variety of listening attachments (inductive telecoil couplers called neckloops, and the typical earbud or headphone type accessories) permit users of telecoil equipped hearing aids to join others in understanding more with the use of ALS.
1. FM Systems-
Sound, via microphone or public address system, is fed into an FM transmitter. It sends sound to small, individual FM receivers. Hearing-aid users whose aids have telecoils set the aid on the "T" setting and use a neckloop listening attachment; earphones are used by everyone else.
Major Advantages: FM systems produce an excellent sound quality. Users have freedom to choose their own seating locations. The systems are not subject to electrical interference and are highly portable, simple and inexpensive to install. Maintenance and operating costs are low because the systems are highly reliable. Also, several frequencies are available.
2. Induction Loops -
Major Disadvantages: The major disadvantages of an FM system are its initial equipment costs, which is greater than that for the AM system or the audio loop system, and restricted access (service is limited to the number of receivers). It transmits through walls so adjacent rooms should be equipped with other frequencies to avoid interference. Costs: Transmitters range from $350 to $2,000 each and receivers from $50 to $350. A typical system costs about $1,500.
A loop of wire circling the room (or part of the room) near a ceiling or floor, receives input from a PA or microphone through an amplifier and transmits the sound by creating a magnetic field within the loop. This field can be picked up by listeners with hearing aids on the "T" setting or with telecoil equipped receivers and an ear-piece. The receiver is equipped with an amplifier so that the sound level can be controlled by the user.
Major advantages: No special receivers are needed by people whose hearing aids are equipped with telecoils. Prepackaged systems can be easily installed in small and medium-sized spaces, are very inexpensive, and portable.
Major Disadvantages: Persons must sit within the loop and must have telecoil equipped hearing-aids or must be provided with loop receivers. Sound quality is often uneven throughout the looped area Fluorescent lighting can interfere with transmission. The electromagnetic field signal can "spill over" into adjacent areas at sides, above, and below. Temporary or portable loops are available but cannot be moved without difficulty. Systems for large areas are complex to install and a high-powered amplifier is required. Skilled professional installation is generally required in large areas, and labor to install a concealed or aesthetically acceptable large area system can be time-consuming and expensive. Costs: Loops range in cost from $350 for a small room to as much as $1,000 for a large loop and a powerful amplifier. Loop receivers cost about $75 each. A typical system costs about $1,000 or less.
3. Infrared -
Infrared systems use invisible, harmless light beams in the infrared range of the spectrum to carry information from a transmitter connected to a PA system or microphone to a special portable receiver worn by the listener and fitted with neckloops, earbuds or headphones to meet the user´s needs.
Major advantages: For persons with mild to moderate losses of hearing, the sound quality is good. The system is easy to operate and is not subject to electrical interference. It is contained within walls of the area and it´s the only system appropriate for confidential transmission.
4. AM Systems -
Major disadvantages: Infrared light is present in sunlight, incandescent light, and fluorescent light, so large amounts of such light in the room may produce interference. Receivers must be within line of sight of the transmitter. Costs: Receivers average about $120 to $300 each while transmitters are $1,300 to $1,800, depending on power and other characteristics. A typical system costs about $2,000.
AM systems are similar to FM systems. Receivers, which may be AM radios in some cases, pick up the signal broadcasted from an AM radio transmitter coupled to a microphone or PA system. Again, users need to have the appropriate listening attachments (neckloops, earbuds or headphones) on the receivers to meet the user´s needs.
Major advantages: The technology is both simple and inexpensive. Users have the freedom to choose where they want to sit. Users can bring their own personal AM radio and attachments and fine-tune to the broadcast.
FEDERAL TECHNICAL REQUIREMENTS -
Major Disadvantages: AM systems have relatively poor sound quality (they are subject to the same sources of interference that often disrupt AM radios) and they do not perform well in buildings with substantial amounts of structural steel. They are rarely used now and suppliers may be hard to find. Costs: Transmitters cost from $350 to $1,000 and receivers from $10 to $35.
Specifications for assistive listening systems in the current federal accessibility requirements under the Architectural Barriers Act are prescribed in sections 4.1.2, 4.33.6,4.33.7 and A4.33.7 of the Uniform Federal Accessibility Standards (49 Fed. Reg. 31528) issued August 7, 1984. 4.1.2
New Construction (18) Assembly Areas: (b) Assembly areas with audio-amplification systems shall have a listening system complying with 4.33 to assist a reasonable number of people, but no fewer than two, with severe hearing loss. For assembly areas without amplification systems and for spaces used primarily as meeting and conference rooms, a permanently installed or portable system shall be provided. If portable systems are used for conference or meeting rooms, the system may serve more than one room.
4.33.6 Placement of Listening Systems
- If the listening system provided serves individual fixed seats, then such seats shall be located within 50 ft. (15m) viewing distance of the stage or playing area.
4.33.7 Types of Listening Systems -
Audio loops and radio frequency systems are two acceptable types of listening systems. 4.33.7 Types of Listening Systems - A listening system that can be used from any seat in a seating area is the most flexible way to meet this specification. Earphone jacks with variable volume controls can benefit only people who have slight hearing losses and do not help people with hearing aids. At the present time, audio loops are the most feasible type of listening system for people who use hearing aids, but people without hearing aids or those with hearing aids not equipped with inductive pickups cannot use them. Loops can be portable and moved to various locations within a room. Moreover, for little cost, they can serve a large area within a seating area. Radio frequency systems can be extremely effective and inexpensive. People without hearing aids can use them but people with hearing aids need custom-designed equipment to use them as they are presently designed. If hearing aids had a jack to allow a by-pass of microphones, then radio frequency systems would be suitable for people with and without hearing. Some listening systems may be subject to interference from other equipment and feedback from hearing aids of people who are using the systems. Such interference can be controlled by careful engineering design that anticipates feedback and sources of interference in the surrounding area.
Information about assistive listening systems is available from several sources. Three national organizations are listed below and other local information sources are listed in the appendix. The Access Board does not endorse these organizations or any information they may provide. Self-Help for Hard of Hearing People (SHHH) 7800 Wisconsin Avenue, Bethesda, Maryland 20814 - A nonprofit educational organization of hearing impaired people with chapters in 48 states and a national demonstration center where assistive listening devices and systems are shown. SHHH publishes a bimonthly journal and disseminates information on a variety of topics including technical information on assistive listening systems: National Association of the Deaf (NAD) 814 Thayer Avenue Silver Spring, Maryland 20910 - A nonprofit organization of deaf people the NAD has an assistive devices center where assistive listening systems are demonstrated: National Information Center on Deafness Gallaudet University Washington, DC 20002 - The Center offers listings of assistive devices demonstration centers across the nation and technical assistance on installing assistive listening systems.
- Assistive Listening Systems - Demonstration Centers: This list was developed by Fellendorf Associates, Inc., 7 Skyview Circle, Keene NH 03431 and SHHH, The list is not necessarily complete and is subject to change. Assistive listening systems are intended to help adults and children to cope more effectively with their hearing impairment at home, at work, at school, and in their communities. While hearing aids are an example of a personal listening device, generally they are not included in demonstration centers such as those listed here. Demonstration centers are open to the hearing impaired public and those who work with them. They provide an opportunity to try out various devices and systems which might prove helpful. Some centers dispense devices and systems as well as demonstrate them. ARIZONA - Sunburst Tele-Comm, Inc. 1016 North 32nd St., Suite 6A Phoenix, AZ 85008 Tel: (602) 274-0203 (v) Contract: Saul H. Moss; Tucson Hearing Society University of Arizona Dept. of Speech and Hearing Tucson, AZ 85721 Tel: (602) 621-7070 (v) Contact: Anne Lanshe-Oyler; CALIFORNIA - House Ear Institute 256 South Lake Street Los Angeles, CA 90057 Tel: (213) 483-4431 (v) 484-2642 (TDD) Contact: William F. House; H.E.A.R. Center Providence Speech & Hearing 1301 Providence Avenue Orange, CA 92668 Tel: (714) 639-4990 (v) Contact: Donna Greenfield; Hearing Society for the Bay Area 20 Tenth Street, Second Floor San Francisco, CA 94103 Tel: (414) 863-4710 (v) 863-2550 Contact: John Darby; COLORADO - The Hearing Store 2308 South Colorado Blvd. Denver, CO 80222 Tel: (303) 757-4327 (v) Contact: Bruce D. Schachterle; DISTRICT OF COLUMBIA - Gallaudet Assistive Devices Center Dept. of Audiology Gallaudet University Kendall Green Washington, DC 20002 Tel: (202) 651-5328 (v) Contact: Cynthia Fernandez; FLORIDA - Ralph J. Baudhin Oral School Nova University 3375 S.W. 75th Avenue Fort Lauderdale, FL 33314 Tel: (305) 475-7075 (v) Contact: Barbara Packer; Hearx 412 Hollywood Mall Hollywood, FL 33021 Tel: (305) 981-8233 (v) Contact: Donna Taylor; ILLINOIS - Charles Siberman AD Center Chicago Hearing Society 10 West Jackson Blvd. Chicago, IL 60604 Tel: (312) 939-6888 (v) Contact: Daria Popowych; Sound-Resources, Inc. 201 East Ogden Hinsdale, IL 60521 Tel: (312) 323-7970 (v) Contact: Barbara Carlson; KANSAS - Institute of Logopedics 2400 Jardin Drive Wichita, KS 67219 Tel: (316) 262-8271 (v) Contact: Karen Black Kramer; MARYLAND - Demonstration Center of ALDS The John Hopkins Hospital, 4th floor Carnegie Building, 600 N. Wolfe Street Baltimore, MD 21205 Tel: (301) 955-6151 (v) (243) 966-5157 (TDD) Contact: Hiroshi Shimizu; Hearing and Speech Agency of Metropolitan Baltimore, Inc. 2220 St. Paul Street Baltimore, MD 21210 Tel: (301) 243-3800 (v) 243-1274 (TDD) Contact: Clifford Lull; Self Help for Hard of Hearing People, Inc. 7800 Wisconsin Avenue Bethesda, MD 20814 Tel: (301) 657-4112 (v) 657-2249 (TDD) Contact: Julius Kopit; Potomac Telecom, Inc. 1010 Rockville Pike Rockville, MD 20852 Tel: (301)762-0851 Contact: Patricia Relihan; National Association of the Deaf 814 Thayer Avenue Silver Spring, MD 20910 Tel: (301) 587-1788 (v/TDD); MASSACHUSETTS - The Boston Guild Demonstration Center The Boston Guild for the Hard of Hearing 283 Commonwealth Avenue Boston, MA 02114 Tel: (617) 267-4730 (v) 267-3496 (TDD) Contact: Kevin Donahue; The Clarke School for the Deaf Round Hill Round Northampton, MA 01060 Tel: (413) 584-3450 (v) 586-2879 (TDD) Contact: B. David Shea; MISSOURI - Timbre Hearing and Speech Centers Bannister Mall 5600 East Bannister road, #189 Kansas City, MO 64137 Tel: (816) 765-7772 Contact: Charles Johnston; NEW YORK - Hearing Rehabilitation Center Albany Medical Center Hospital New Scotland Avenue Albany, NY 12208 Tel: (518) 445-3125 (v) Contact: Donna Wayner; Mill Neck Foundation P.O. Box 200 Mill Neck, NY 11765 Tel: (516) 822-3880 (v) Contact: Louis Frillman; Manhattan Eye, Ear & Throat Hospital 210 East 64th Street New York, NY 10021 Tel: (212) 605-3739 (v) Contact: Joseph Montano; NY League for the Hard of Hearing 71 West 23rd Street New York, NY 10010 Tel: (212) 741-7650 (v) 255-1932 (TDD) Contact: Joshua Gendel; Assistive Devices Demonstration Center Meeting House, Oceanside Free Library Davison Avenue Oceanside, NY 11572 Tel: (516) 457-6400 (v) 545-7514 (TDD); National Technical Institute for the Deaf One Lomb Memorial Drive P.O. Box 9887 Rochester, NY 14623 Tel: (716) 457-6400 (v) 457-2181 (TDD) Contact: William Castle; Burke Rehabilitation Center 785 Mamaroneck Avenue White Plains, NY 10605 Tel: (914) 948-0050 (v) Contact: Kate Halvorson; OKLAHOMA - Hearcare 5077 South Yale Tulsa, OK 74135 Tel: (918) 333-8910 (v) Contact: Karen Cox; OREGON - Eugene Hearing and Speech Center 1202 Almaden Street P.O. Box 2087 Eugene, OR 97402 Tel: (503) 485-8521 (v) Contact: Craig Ford; Sound Solutions 5210 S.E. 52nd Portland, OR 97206 Tel: (503) 774-3751 (v) 774-7247 (TDD) Contact: Barbara Power; PENNSYLVANIA - Johnson ENT Associates 321 Main Street Johnstown, PA 14901 Tel: (814) 536-5161 (v) Contact: Mary Lou Astorino; Hearing Resource Center Chestnut Hill Hospital, Med. Off. Bldg. 8815 Germantown Avenue, Suite 16 Philadelphia, PA 19118 Tel: (215) 247-4400 (v) Contact: Shelly Jackson; Berks County Association for the Hearing Impaired 223 North 6th Street Reading, PA 19601 Tel: (215) 373-6992 (v) 374-7300 (TDD); TENNESSEE - Bill Wilkerson Hearing and Speech Center 1114 19th Avenue South Nashville, TN 37212 Tel: (615) 320-5333 (v) Contact: Judy Vendress; TEXAS - Callier Center for Communication Disorders University of Texas at Dallas 1966 Inwood Road Dallas, TX 75235 Tel: (214) 738-3000 (v) Contact: Carolyn Musket; WASHINGTON - Medico, Inc. 625 Peach Portal Drive Blaine, WA 98230 Tel: (206) 332-6114 (v) Contact: Reni Saffran; Let´s Talk Assistive Devices Demonstration Center 921 Lloyd Building, 603 Stewart Seattle, WA 98101 Tel: (206) 340-8255 (v) Contact: Carol Killingsworth; Services for Deaf & Hard of Hearing People North 1206 Howard Street Spokane, WA 99201; WISCONSIN - North Central Technical Institute Program for Hearing Impaired People 1000 Campus Drive Wausau, WI 54401 Tel: (715) 675-3331 (v) 675-6341 (TDD) Contact: David Pagel; CANADA - The Canadian Hearing Society 271 Spadina Road Toronto, Canada M5R 2V3 Tel: (416) 964-9595 (v) Contact: Peggy Hewitt;