AUDIO FREQUENCY INDUCTION LOOP SYSTEMS

An induction loop system consists of an amplifier and a loop. The amplifier can be connected to a sound source such as a TV or Radio, a PA/VA system or a dedicated microphone. It then amplifies this sound signal and sends it out, in the form of an alternating current, through the loop. The loop itself consists of an insulated wire, one turn of which is placed around the perimeter of the room. When this alternating current from the amplifier flows through the loop, a magnetic field is created within the room. If a hearing aid user switches his hearing aid to the T position, the telecoil in the hearing aid picks up the fluctuations in the magnetic field and converts them into alternating currents once more. These are in turn amplified and converted by the hearing aid into sound. The magnetic field within the loop area is strong enough to allow the person with the hearing aid to move around freely within the room and still receive the sound at a good, comfortable listening level.

Why an induction loop?
In a noisy environment, or one in which reverberations and echoes are noticeable, we all find it difficult at times to hear and understand what is said. But for a person with impaired hearing, wearing a hearing aid, it can be almost impossible to hear and understand under such conditions.

Sound comes to the user in a pure, undistorted form, not affected by the distance the listener is from the sound source, nor by any interfering background noises in the room.

In the sheltered or residential environment, many modern TV sets have a SCART connection, which permits a direct connection to a loop amplifier, so that the hearing aid user can listen, via the magnetic field of the induction loop, without other persons in the vicinity being disturbed by sound from the TV (or radio). Some induction loop amplifiers are also available with facilities for doorbell or telephone ringing signals to be transmitted over the loop in such an environment.