by Cory Schaeffer
This articles presents the new rules that the US Department of Justice released in 2010 in regards to ADA compliance and assistive listening.
Assistive Listening and ADA Compliance
As the name applies, an Assistive Listening System provides an enhanced personal audio experience for those who might need extra assistance in hearing. This can be due to a hearing loss or the ambient acoustic environment. We’ve all experienced venues where, due to reverberation, poor acoustics, inadequate sound systems and/or poor microphone technique, it’s been a challenge to “hear”. We all experience some degree of hearing loss.
What audio sources should you put into an assistive listening system? Some AV integrators will send all audio through the ALS system, which causes intelligibility issues. There is no need to send sources other than voice through an ALS system. The best solution would be to use a separate output from the mixer. Allow for a separate mix to the assistive listening transmitter so that you can leave out things that are unimportant to these listeners. For example, the priority should be the channels which have an emphasis on speech. Many of the other channels can be greatly reduced or even completely omitted from the ALS mix.
There are three types of technology used for assistive listening: RF (radio frequency), IR (infrared) and IL (induction loop). All of these technologies produce much of the same result: the audio source transmitted wirelessly to a personal receiver or directly to a compatible hearing-aid.
In an RF system, the signal is transmitted over radio frequencies (specifically the FCC mandated 72 and 216 MHz bands) to a personal receiver. The advantage of RF technology is that there are no “line-of-site” issues and the technology can cover a wide area indoors or outdoors. This technology uses an antenna and the placement of the antenna is critical to the performance and range of an RF system. Ideally for optimum quality, the antenna should be in the vicinity of the receivers. The transmitter may be installed anywhere, however the antenna should be located at a high elevation relative to the receivers. An RF assistive listening system is typically the least expensive. For users with hearing aids that have tele-coil (T-Coil) capabilities, there is a neck loop that can be used with the personal RF receivers which allows the audio signal to be transmitted via magnetic field to the users’ hearing aid.
An IR system uses infrared light to transmit audio, just like a television remote control. The advantage of IR technology is that the system is secure and you can be confident that the audio signal will never leave the room the system is used in. Light does not transmit through walls as an RF system can. The challenge of IR is that the listener should be within “line-of-site” to the emitter/radiators. This will affect the range and coverage of an IR system. Range can be expanded with additional emitters/radiators. The shape of the room, the coverage and line-of-site requirements usually require more thought and consideration during the installation. The height of the emitters/radiators is a critical consideration as well. For users with a hearing aid that has tele-coil (T-Coil) capabilities, there is a personal neck loop that can be used with the personal IR receivers which will allow the audio signal to transmit magnetically to the users hearing aid.
In an Induction Loop system, an integral wire is connected to a loop driver and installed around the room in a variety of ways creating an induction field that can be picked up by hearing aids with a tele-coil (T-Coil). Many venues and users alike enjoy this type of an assistive listening system because the users’ disability is invisible as they simply use their hearing aids to receive the audio signal. There would be no need to ask for a receiver. There is also no need to wear something that draws attention to their hearing disability. Loop receivers can be added to an induction loop system to accommodate those that do not have a T-coil hearing aid or for those that do not wear a hearing aid.
There are new rules that the US Department of Justice released in 2010 in regards to ADA compliance and assistive listening. These new updated rules apply to all new construction and alterations since March 15, 2012 and are mandatory by law. The number of receivers and number of hearing aid compatible receivers depends on the total occupancy of the venue. http://www.hearingchattanooga.org/news_items/ADA%20Standards%20219%20+%20706ALDs%20%20.pdf
Please refer to the table below for the requirements
Table 219.3 Receivers for Assistive Listening Systems
|Capacity of Seating
in Assembly Area
|Minimum Number of
Contact Listen for customized quote to accommodate email@example.com
|Minimum Number of
to be Hearing-aid Compatible(using Listen LA-166)
|50 or less||2||2|
|51 to 200||2, plus 1 per 25 seatsover 50 seats*||2|
|201 to 500||2, plus 1 per 25 seatsover 50 seats*||1 per 4 receivers*|
|501 to 1000||20, plus 1 per 33 seatsover 500 seats*||1 per 4 receivers*|
|1001 to 2000||35, plus 1 per 50 seatsover 1000 seats*||1 per 4 receivers*|
|2001 and over||55 plus 1 per 100 seatsover 2000 seats*||1 per 4 receivers*|
*Or fraction thereof