Assistive Listening
Systems
There are approximately 21 million people in the United States
with hearing impairments. Many of these individuals use hearing
aids to supplement their hearing. However, individual hearing
aids function best in close settings when ambient noise is minimal.
In larger rooms, hearing aid users have difficulty hearing speakers,
presenters, or performers because the aid not only amplifies the
desired sound, but also other noises in the room. Assistive listening
systems, on the other hand, pick up sound at, or close to, its
source and delivers it directly to the listeners ear without extraneous
noise, reverberation, or distortion.
Types of Assistive Listening Systems
Conventional Induction Loop
Amplifier drives an induction loop that surrounds the listening
area.
Advantages:
- Requires little or no administration of receivers, if most
people have telecoil equipped hearing aids. Induction receiver
must be used where hearing aids in use are not equipped with
telcoils.
- Induction receivers are compatible with all loop systems.
- May be used separately or integrated with existing P.A. systems.
- Portable systems are available for use with small groups
of listeners.
Disadvantages:
- Signal spill-over to adjacent rooms.
- Susceptible to electrical interference.
- Limited portability.
- Requires installation of loop wire. Installation may be difficult
in pre-existing buildings.
Typical Applications:
- Service Counters
- Ports of Transportation
- Public Transportation vehicles
- Tour Buses
- Meeting Rooms
- Conference Rooms
- Classrooms
3D Loop System
Amplifier drives a 3D mat that is placed under the carpet of
the listening area.
Advantages:
- Requires little or no administration of receivers, if most
people have telecoil equipped hearing aids.
- Induction receivers are compatible with all loop systems.
- May be used separately or integrated with existing P.A. systems.
- Three dimensional reception of loop signal regardless of
telecoil position.
- 3D loop mats must be separated by 6 feet to avoid signal
spill-over.
Disadvantages:
- Requires installation of 3D loop mats. Installation may be
difficult in pre-existing buildings.
- If listener does not have telecoil-equipped hearing aid then
requires administration and maintenance of receivers.
- Limited portability.
- Susceptible to electrical interference.
Typical Applications:
- Service Counters
- Ports of Transportation
- Court Rooms
- Museums
- Meeting Rooms
- Conference Rooms
- Classrooms
Infrared Light
Amplifier drives emitter panels covering listening area.
Advantages:
- Transmission does not travel through walls or other solid
surfaces.
- Insures confidentiality.
- Infrared receivers compatible with most infrared emitters.
- May be used separately or integrated with existing P.A. systems.
Disadvantages:
- Receivers required for everyone. Requires administration
and maintenance of receivers.
- Ineffective in direct sunlight.
- Careful installation required to insure entire listening
area will receive IR signal.
- Lifetime of emitters varies with company.
- Susceptible to electrical interference when used with induction
neckloop/silhouette.
Typical Applications:
- Indoor Service Counters
- Churches and Temples
- Court Rooms
- Indoor Arenas
- Meetings Requiring Confidentiality
- Conference Rooms
- Classrooms
- Sport Stadiums (indoors only)
FM Broadcast
FM base station or personal transmitter broadcasts signal to
listening area. The Drake Audio Accent and ALT72 systems are FM
broadcast systems.
Advantages:
- Highly portable when used with body-worn personal transmitter.
- Easy to install.
- Multiple frequencies allow for use by different groups within
the same area (e.g. multi-language translation).
- May be used separately or integrated with existing P.A. systems.
Disadvantages:
- Signal spill-over to adjacent rooms.
- Receivers required for everyone. Requires administration
and maintenance of receivers.
- Some systems more susceptible to radio wave interference
and signal drift than others.
- Susceptible to electrical interference when used with induction
neckloop/silhouette.
Typical Applications:
- Service Counters
- Churches and Temples
- Court Rooms
- Indoor or Outdoor Guided Tours
- Tour Buses
- Theaters
- Museums
- Theme Parks
- Arenas
- Retirement/Nursing Homes
- Hospitals
- Auditoriums
- Meetings Rooms
- Conference Rooms
- Classrooms
- Sport Stadiums
