United States Architectural & Transportation
Barriers Compliance Board
1331 F Street, N.W., Suite 1000
Washington, D.C. 20004-1111
(202) 272-5434 (Voice or TDD)

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.

AM Systems - 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. 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.

FEDERAL TECHNICAL REQUIREMENTS - 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 Accessible Buildings: 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.

Resources - 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) 8630 Fenton Street, Suite 820, Silver Spring, MD 20910-3876  - 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.

APPENDIX - 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.

This public document was found at http://www.faa.gov/arp/c1.htm, but they've since removed it from website. I have changed the format just a bit to make this document easier to read.