What are Assistive Listening Devices
Assistive Listening Devices (ALDs) are specialized tools designed to improve the ability of individuals with hearing loss to hear with clarity and understand sounds with direct sound amplification or visual or vibrotactile alerts.
Assistive devices include an array of technology: Television and telephone aids, alerting or signaling devices, and personal or large-area assistive listening systems. These devices are crucial in ensuring accessibility in environments where there is a lot of background noise, in public spaces, or during meetings and presentations.
Types of Assistive Listening Devices (ALDS)
Assistive devices are also known as auxiliary aids, assistive listening devices or ALDs.
- FM Systems: These use radio frequency signals to transmit sound directly from the source to the wearer's ear, minimizing background noise.
- Infrared Systems: Similar to FM systems, but use infrared light to transmit sound. Ideal for maintaining privacy in settings like courtrooms or movie theaters.
- Induction Loop Systems: Utilize electromagnetic energy to transmit sound. They are often installed in public spaces and work with the telecoil setting in many hearing aids.
- Personal Amplifiers: Portable devices that amplify sound close to the listener while reducing background noise.
When they are required?
Under the Americans with Disabilities Act Accessibility Guidelines (ADAAG) certain fixed seating assembly areas that accommodate 50 or more people or have audio-amplification systems must have permanently installed assistive listening systems. Other assembly areas must have permanent systems or an adequate number of electrical outlets or other wiring to support a portable system. The minimum number of receivers must be equal to four percent of the total number of seats, but never less than two. Additionally, a special sign indicating the availability of the system is required.
Sample signage can be found on our website (https://www.sf.gov/get-disability-access-posters-and-signs).
Why Are They Required?
In some settings permanently installed assistive listening systems are not available; however, when it is expected that 50 or more people will be in attendance or an accommodation request has been made a portable assistive listening device should be provided. The assistive listening device usually uses a microphone to capture an audio source near its origin and broadcasts it wirelessly over an FM (Frequency Modulation) transmission, IR (Infra Red) transmission, IL (Induction Loop) transmission, or other transmission method. The person who is listening may use an FM/IR/IL Receiver to tune into the signal and listen at his/her preferred volume.
Resources
Questions and inquiries about the portable assistive listening device can be addressed to MOD. For additional resources for hard-of-hearing individuals, you can contact the following resource:
Hearing and Speech Center of Northern California 1234 Divisadero Street
San Francisco, CA 94115
Phone: 415. 921.7658