Induction Loops & Induction Loop Systems
Audio Frequency Induction Loop Systems are designed to work in conjunction with a hearing aid. They are not designed to replace the hearing aid and only work if the hearing aid is fitted with a “T” switch. When the switch is in the “T” position the hearing aid microphone is switched off and the user only hears the sound from the induction loop system.
All sounds in an area will be heard whether they are the desired sounds or not. The hard of hearing person finds it more difficult to separate the sounds from unwanted background noise. A standard hearing aid will amplify all sounds and although this can assist in hearing, it does not help in an environment where there is significant background noise.
An Induction Loop system comprise of a microphone, amplifier and loop of wire. The microphone must be situated close to the speaker as this increases the level of the sound relative to background noise. The amplifier converts this sound into an electric current, which is driven through the loop of wire. The magnetic field from the loop is received by the hearing aid which converts it back to sound for the listener – with the switch in the “T” position.
The key point to remember is that the hearing aid user hears what goes through the microphone – both the speaker’s voice and any background noise. To benefit from induction loops the speaker’s voice must ALWAYS be close to the microphone to ensure that it predominates over background noise.
Typical applications for Induction Loop systems cover hotel counters, reception desks, airport check-in desks, small or large conference rooms, churches, taxis, buses and trains.
They can interface with audiovisual systems and can be used in conjunction with the telephone. Loops are also available for domestic use with the TV or telephone or even at the dining table.
For Room systems (otherwise known as Room Loops) it is important to have answers to many questions before starting, such as;
- The size of the room.
- How is the room to be used and will you have audience participation? i.e. in a cinema there is no audience communication but at a conference questions will be asked from the audience. This will indicate the microphone requirements.
- Where the loop can or must be fitted.
- Is there a suspended ceiling – is it a listed building.
- If there is not a suspended ceiling can the loop be fitted to the skirting boards?
- The construction of the building and whether there are steel girders that can distort the magnetic field.
- What about air-conditioning systems as they can interfere.
- What is the floor – is it carpeted or solid – these factors affect the acoustics.
- Is there any equipment now or in the future that will produce magnetic interference – such as lifts, stage lighting, under floor heating, electronic dimming equipment etc.
- Does the system have to integrate with an AV system?
- What about fire alarm input.
- Installation is very important and so is the selection of the microphones for the application. It has to be neat and tidy and carefully planned and tested properly when completed.