36 CFR Parts 1190 and 1191 ADA and ABA Accessibility Guidelines - Preamble (Discussion of Comments and Changes)

706 Assistive Listening Systems

Section 706 provides specifications for assistive listening systems. Assistive listening systems pick up sound at or close to its source and deliver it to the listener’s ear. This more direct transmission improves sound quality by reducing the effects of background noise and reverberation and, as needed, increasing the volume. These devices serve people who are hard of hearing, including those who use hearing aids. Assistive listening systems are generally categorized by their mode of transmission. Acceptable types of assistive listening systems include induction loops, infrared systems, FM radio frequency systems, hard-wired earphones, and other equivalent devices. A definition for "assistive listening systems" has been included in the final rule (section 106). Provisions address receiver jacks (706.2), compatibility with hearing aids (706.3), and system quality and capability (706.4 through 706.6).

Comment. Receivers are required to have a c inch standard mono jack so that users can use their own cabling as necessary. The proposed rule allowed other types of jacks where compliant adapters were provided (706.3). Comments strongly supported the requirement for the c inch mono jack. Some commenters noted that this type of jack should be provided in all cases and that alternative types should not be allowed to avoid issues such as who is responsible for the provision of adapters.

Response. In the final rule, the Board has specified that receivers include a c inch (3.5 mm) standard mono jack and has removed language concerning other jack types and adapters (706.2).

Section 706.3 specifies that receivers required to be compatible with hearing aids (25%) must be neck loops since this type interfaces with hearing aid T-coils. Many comments supported this provision and no changes to it have been made in the final rule.

The performance of assistive listening systems is a concern among users. The quality and capability of systems largely determine the quality of sound transmission. Sound quality, internal noise, signal-to-noise ratio, signal strength, and boost vary among products. As a result, some systems do not adequately meet the needs of people who are hard of hearing. For example, the boost of some products may amplify sound adequately for people with mild hearing loss but not for those with profound hearing loss.

In the belief that standards should be developed to provide guidance in selecting products of sufficient quality and capability, the Board funded a study on assistive listening systems that was completed in 1999. Conducted by the Lexington Center, this project included collecting information on assistive listening systems, a review of the state-of-the-art with respect to assistive listening systems, and a survey of consumers, service providers, dispensers and manufacturers to determine how effective assistive listening systems are at present and what the major problems, limitations, and complaints are regarding existing systems. With this information, the researchers developed objective means for specifying the overall characteristics of any assistive listening system, from sound source to listener’sear, to be able to predict how well the system will work in practice and to determine objective criteria for establishing guidelines or recommendations for the use of assistive listening systems in public places.

The criteria recommended by this research include:

• a signal-to-noise ratio of at least 18 decibels measured at the earphones

• the capability of receivers to deliver a signal with a sound pressure level of at least 110 decibels and no more than 118 decibels with a dynamic range on the volume control of 50 decibels

• peak clipping levels at or below 18 decibels down from the peak level of the signal

Comment. The Board sought comment on whether the criteria developed through the Lexington Center research should be included in the final rule (Question 30). Commenters overwhelmingly supported the inclusion of specifications for the performance and sound quality of assistive listening systems.

Response. The Board has included performance criteria for assistive listening systems based on the Lexington Center research that address the sound pressure level (706.4), signal-to-noise ratio (706.5), and peak clipping level (706.6).

A report from the Lexington Center on this research, "Large Area Assistive Listening Systems: Review and Recommendations," is available from the Board and its website at www.access-board.gov. Additional resources stemming from the project, including a series of technical bulletins on assistive listening systems, are also available.

Section 706 provides specifications for assistive listening systems. Assistive listening systems pick up sound at or close to its source and deliver it to the listener’s ear. This more direct transmission improves sound quality by reducing the effects of background noise and reverberation and, as needed, increasing the volume. These devices serve people who are hard of hearing, including those who use hearing aids. Assistive listening systems are generally categorized by their mode of transmission. Acceptable types of assistive listening systems include induction loops, infrared systems, FM radio frequency systems, hard-wired earphones, and other equivalent devices. A definition for "assistive listening systems" has been included in the final rule (section 106). Provisions address receiver jacks (706.2), compatibility with hearing aids (706.3), and system quality and capability (706.4 through 706.6).

Comment. Receivers are required to have a c inch standard mono jack so that users can use their own cabling as necessary. The proposed rule allowed other types of jacks where compliant adapters were provided (706.3). Comments strongly supported the requirement for the c inch mono jack. Some commenters noted that this type of jack should be provided in all cases and that alternative types should not be allowed to avoid issues such as who is responsible for the provision of adapters.

Response. In the final rule, the Board has specified that receivers include a c inch (3.5 mm) standard mono jack and has removed language concerning other jack types and adapters (706.2).