What is an Induction Loop?
An induction loop allows users with a telecoil equipped hearing device (switched to the T or MT position) or anyone wearing an Induction Loop Receiver to listen inductively to sound transmitted through a magnetic field without the interference of airborne background noise.
The telecoil is familiar to many as the method used by the telephone companies to make it easier for a hearing aid user to use a telephone. The hearing aid picks up the sound via the magnetic field generated by the diaphragm coil in the receiver of a telephone.
In recent years, legislation has lead to induction loop systems have to be installed in public places such as hospitals, induction loop in civic centres, induction loop in town halls, libraries, induction loop churches, cinemas, and induction loop at service counters.
An induction loop can be used to increase the range of Sound Reinforcement Equipment; a PA system in a building can connect to the Induction Loop Amplifier and then via the Loop cable be transmitter to hearing air users.
The Inductive loop can also stand alone, being used just for the benefit of the hearing aid user.
How does an Induction Loop Work?
When an alternating current is passed through a circuit, a magnetic field is generated around the wire. If a second circuit is brought within this magnetic field, a corresponding alternating current is created within the second circuit; the technical term for this is "induced". Hence the term "induction loop”. This particular electromagnetic principle is the basis on which many everyday electrical products work.
An induction loop system "induces" hearing aids or an Induction Loop Receiver in the same way. An Induction Loop System consists of an amplifier and a loop. The amplifier is connected to a sound source such as a Public Address system or an audio devise i.e. Television Video or DVD player connected to the Induction Loop. It amplifies the sound signal and sends it out, in the form of an alternating current, through the loop. The loop itself consists of insulated wire, which is placed around the perimeter of the room. When the alternating current from the amplifier flows through the loop, a magnetic field is created within the room. The magnetic field "induces" the hearing aid.
If a hearing aid user switches to the T or MT position on their hearing device or if an individual is wearing an Induction Loop Receiver, the telecoil in the hearing device or Induction Loop Receiver 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 or the Induction Loop Receiver into sound. By using this method of sound reproduction the user is able to clearly distinguish sound and speech from the “induction loop” over an above the background noise.
Why use 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. For a person with impaired hearing wearing a hearing aid, it can be almost impossible to hear and understand under such conditions.
Sound from an induction loop system comes to the user in pure, undistorted form. It is not affected by the distance the listener is from the sound source, provided they are within the limits of the loop.
In a sheltered or residential environment, an Induction Loop system permits the hearing aid or Induction Loop Receiver user to hear without other individuals in the area being disturbed by the sound.
The disabled act of 1995 clearly defines the requirements for public buildings to not discriminate against anyone, this includes, the partially deaf, completely deaf and deaf blind. The careful use of Inductive Loops is one method of ensuring that legislation is complied with, and needs to be in place by Oct 2004.