Hearing Assistance Systems and the ADA

About twenty years ago there were a sets of regulations outlined that addressed the needs of persons with special handicaps. These needs are handled differently in various countries around the world, but the general intent is to assure that buildings and facilities are equally accessible by everyone. In the United States this is commonly referred to as the ADA, or Americans with Disabilities Act. The standards can be found in the Code of Federal Regulations (CFR), Part 36 (www.ada.gov). The ADA addresses many aspects of the workplace, public spaces, and entertainment venues. It is extensive and sometimes not very well understood.

This discussion is to center about the implementation of Assistive Listening (or sometimes called Hearing Assistance) systems. The 1991 Standards, at section 4.1.3(19)(b), require assembly areas, where audible communication is integral to the use of the space, to provide an assistive listening system if they have an audio amplification system or an occupant load of 50 or more people and have fixed seating. The 2010 Standards at section 219 require assistive listening systems in spaces where communication is integral to the space and audio amplification is provided. The new code does not define the minimum occupancy of the space.

As an AV consultant, we see many different types of assistive listening systems installed. The two most common and easily upgradable are the types that use Infrared light (IR) and FM radio transmission (RF). The hard-wired (systems with headphone jacks in the chairs) and Induction Loop type systems are much less frequently used due to installation and long-term maintenance issues. More information about Induction Loop systems can be found here: www.hearingloop.org

Beyond the selection of the signal transmission method, which I will discuss below, there are other considerations to be thought-out in order to arrive at a system specification that will satisfy all of the operational needs of both the owner and the end-users.

• Ergonomic considerations: There is a fairly strong correlation between the population requiring assistive listening devices and those that may also have other physical impairments. A fully able-bodied person can generally use just about any headphone, ear bud, or telecoil coupler that is available in the marketplace, however, persons with other physical disabilities must have devices provided that suit their ability to operate the receiver controls, make connections, if any, and don the listening appliance. Many products on the market are not well-suited for use by this segment of the population. A panel of the typical end-users should be assembled to introduce them to the various options available and to involve the product selection process.
• Equipment Availability considerations: The ADA is very clear about the type of signage, illumination of the signage, and the location of signage that informs the incoming patrons that there is assistive listening equipment available and where it can be obtained. This means that the devices must be located where someone can readily access them and distribute them to those that request them. The equipment can’t be locked away in a cabinet in an office that is in another building that is closed after normal operating hours.
• Equipment Management considerations: There should be a clean place to store the devices when not in use, and a means to keep them charged and ready to use. There is usually a system to check-out the equipment that involves the exchange of a student ID or some other place-holder to assure that the equipment is returned after the event. Equipment must be cleaned so that proper hygiene practices are observed for community shared devices.
• The audio mix for the assistive listening system should be carefully monitored so that it does not include too much sound effects, music, or other sound that is detrimental to the clear understanding of the primary speech and/or singing (this is particularly important in theatrical, music, and sporting venues).
• The Assistive Listening System must be interfaced to the existing audio system so that both microphones and pre-recorded material can be heard.
• The speed of sound is significantly less than the speed of light (RF waves and Light waves), so it is usually necessary and beneficial to add a means to delay the Assistive Listening System signal so that the sound from the PA system arrives at the ears of the listener about the same time that the sound from the earphones is produced, otherwise there will be an echo perceivable by the user that can further impair their ability to understand what is being presented.
• If the equipment is to be used in more than one venue around a campus or school district, it is highly recommended that it all be sourced from the same manufacturer to ensure inter-compatibility. Although there are some standards upon which the manufacturers build their products, there is no guarantee that brand A receivers will function properly with brand B transmitters.

RF transmission systems generally operate in a special FM radio band that is designated for this purpose by the FCC (it is not in the normal FM radio band used by local broadcasters). As a radio-based device, the transmitters broadcast a signal that can be received through walls and have a reception range that can sometimes be as far as 1,000 feet from the transmitter. This means that if adjacent classrooms or theatres are to use the same types of systems, then the frequencies (channels) must be carefully coordinated so that the proper program is heard in each space. Some FM-based systems can operate up to 16 channels without interfering with each-other, while others are limited to just one or two channels of simultaneous operation. The receivers used by the listener must be tuned to the proper channel that matches the program source they are interested-in. The FM transmitter (Radio Signal Modulator) is usually mounted in an equipment rack along with the rest of the audio system for a room. The antenna typically should be located remotely from the transmitter so that it can be positioned where it broadcasts the best signal coverage to the audience area(s). Proper mounting and orientation of the antenna is very important so that the radio waves do not reflect off of nearby metal (widow frames, conduits, pipes, metal wall studs, rebar, tile grid, etc.), and so the antenna directs the RF waves in the proper direction.

IR transmission systems utilize invisible light to transmit the signal. Unlike the RF antenna that can be hidden from sight, the IR emitter panel(s) must be located ‘line-of-sight’ to the audience. The size and quantity of the emitter panels vary by the shape and size of the room to be ‘illuminated’ by the IR light. The advantage that this transmission method has is that the signal stays in the room and will not disrupt similar systems in adjacent rooms. This allows the same receiver to be used in any room that is equipped with IR emitter panels. This is very helpful if there are students that will move between rooms, as they can take the receiver with them as needed. Many commercial venues rely in IR systems so that the program cannot be recorded from outside the performance space.

Similar to the FM systems, there is usually a signal processor that resides in the audio equipment rack, and then the signal is connected to the emitter panel(s) via a coaxial cable. Each system manufacturer has different wiring and powering requirements, so the specific wiring method cannot be predetermined unless the transmitter & antenna / emitter product is selected.

Other considerations are to determine where throughout the campus the assistive listing systems are to be installed. The ADA requires these systems in performance venues of any seating capacity, so lecture halls, gymnasiums, cafetoriums, gymatoriums, theatres, and auditoriums all fall in this category. Based on this new standard, it appears that classrooms now require them if there are audio systems present, however, since an AV system is a very common component in most modern classrooms, so the inclusion of an assistive listening system in the AV layout and design of these spaces should always be considered.

Outdoor venues like soccer fields, football fields, baseball fields, and amphitheatres also require assistive listening systems. These present a bigger challenge as they are much larger spaces and they are typically inherently outdoors and used under full daylight. IR type systems do not work in full sunlight as the sun emits IR energy that is much stronger than the assistive listening system emitter panels can produce. These venues can only use an RF based (FM or Induction Loop) transmitter system. Just as with the adjacent classrooms, adjacent outdoor venues must be designed to operate on different channels.

In schools where multi-lingual events occur, a multi-channel IR or FM Assistive Listening System can be utilized and interpreters can relay the program to the foreign language listeners.

The retrofitting of an entire campus or school district with a quality Assistive Listening System can be a complex project that will require careful integration of the equipment with the existing systems. Each room will undoubtedly have unique issues with the proper placement of equipment, storage and charging facilities, and in the case of RF based systems – frequency coordination. Additionally, the training of staff regarding the proper use and maintenance of the equipment will have to be a part of the project specifications. A professional independent AV Consultant can provide an objective systems design and product specification that can be equitably bid and installed by the successful contractor, and can provide project administration that will assure the school that their funds are responsibly applied.