When the Gerald R. Ford International Airport decided to install hearing loops at every terminal and gate, they called upon the experts at ASCOM to design and install the system. Why trust your hearing to anyone else? We are not happy until EVERYONE can hear!
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When the Gerald R. Ford International Airport decided to install hearing loops at every terminal and gate, they called upon the experts at ASCOM to design and install the system. Why trust your hearing to anyone else? We are not happy until EVERYONE can hear!
But how does all of this work? Many people may not have heard of induction loops, and do not have any idea of the great help an induction loop system can be in compensating for an audio disability.
If a hearing aid user switches their hearing aid to the telecoil (T) position, the telecoil receives the loop signal and the hearing aid converts it into sound. The magnetic field within the looped area is strong enough to allow a hearing aid user to move freely within the looped area and still receive clear sound at a comfortable listening level.
How does an Audio Frequency Induction Loop work ?
In the most basic form, an audio induction loop system consists of a loop of wire around the perimeter of an area that is connected to an induction loop amplifier. An input signal is provided to the induction loop amplifier, and the induction loop amplifier drives an audio current (note current not voltage) through the loop in the form of a strong alternating current. As the alternating current from the amplifier flows through the loop, it creates a magnetic field within the looped area and “induces” the telecoil in a hearing aid , or specifically design induction loop receiver , within the looped area.
When a hearing aid user switches their hearing aid to the “T” position on the hearing aid, the telecoil in the hearing aid picks up the fluctuations in the magnetic field and converts them back into alternating currents. The alternating currents are amplified and converted by the hearing aid into sound.
The input to the induction loop amplifier can be a sound source such as a television or stereo, a public address or sound reinforcement system, a dedicated microphone, or any sound source that users inside the looped area wish to hear more clearly.
Not all loop layouts are a simple single wire surrounding a room, but this explanation illustrates the basic principles.
See the diagram below:
Why use an Audio Induction Frequency Loop ?
People who suffer from hearing loss require more than just increasing the volume of sound into their ears. The loss of hearing is generally associated with the brain’s neurological processing of information. For people with normal hearing, a signal to noise ratio of 6dB is required for a reasonable level of speech intelligibility. This represents quite a noisy background, and includes sounds such as reverberation, air conditioning, ventilation systems or background noise such as those associated with a crowd of people.
When a person loses about 80% of their hearing, they generally need a signal to noise ratio of 15 to 20dB for a reasonable level of speech intelligibility. This can be difficult to achieve unless the desired signal is taken straight from the basic source and transmitted directly through the loop system to avoid any reverberation or additional ambient noise. Delivering a pure, clean signal directly to the hearing aid maximizes the benefits of digital hearing aids and delivers the best possible sound possible to the hearing aid user.
Audio Frequency Induction Loops have the following advantages:
- Using the built-in T coil in the hearing aid means hearing aid user always has their “receiver” with them
- Utilizing the internal tonal correction of the hearing aid maximizes the benefit of the hearing aid
- No additional receiver / headset is needed which eliminates dispensing, retrieving and maintaining receivers / headsets at venues
- Hygiene problems / concerns are eliminated
- Operates in conditions of bright light (both interior or direct sunlight)
- Are the most cost efficient assistive listening technology
Where are Audio Induction Frequency Loops used?
There are two basic environments in which induction loops are used:
transient and
extended time. In both environments, the telecoil capability in the hearing aid is used to listen inductively, which eliminates background noise and greatly increases speech intelligibility for the hearing aid user.
In transient use locations it is impractical to issue and retrieve a receiver / headset and these are often among the worst areas for problems related to speech intelligibility and background noise. The use of an individual's hearing aid is a major step to bringing people with hearing loss back into full contact with their environment. Utilizing a telecoil, the hearing aid user always has their “receiver” with them. Only audio frequency induction loop systems provide this capability.
Typical areas of Transient Use include:
- Drive-thru and pick-up windows such as those founds at restaurants, pharmacies and banks
- Point of sale locations such as ticket counters and check outs
- Reception desks and information kiosks
- Public areas in airports, railway stations, subways, shopping malls etc.
- Elevators, lifts
- Cars, buses, coaches, trams, trains, airplanes, cruise ships
- Museum exhibits
Typical areas of Extended Time Use include:
- Theatre and Performing Arts facilities
- High School and College Auditoriums
- Church Sanctuaries and Worship Centers
- Board rooms and meeting rooms
- Banquet Facilities
- Court rooms and Government chambers
- Sports facilities - Gymnasiums, Natatorium, Stadiums
In extended time use locations there often exists sufficient degradation of signal to seriously effect speech intelligibility. By using an audio frequency induction loop system, no additional equipment, i.e. receivers / headsets, is required if a hearing aid is telecoil equipped. By simply switching to the “T” setting on the hearing aid, the audio signal is received. This eliminates the need for a facility to pass out, retrieve and maintain equipment, as well as eliminating hygienic concerns.
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