Induction Loop Systems
| (sometimes known as Audio Frequency Induction Loops - AFILS) Induction loop systems are often used as an effective way of communicating with people with hearing disabilities. The recipient needs a hearing aid with a “T” switch (stands for telecoil) . On some digital aids no switching is required as the reception is automatic. |
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How they work
The sound source, usually a microphone but it could be any audio source, drives a loop of cable via a special amplifier that creates an electro-magnetic field within the loop. The sound source may be derived from the mixer or pre-amplifier stage of the existing sound system or if necessary it may use a dedicated input source installed at the same time as the loop. The listener within that field uses the hearing aid telecoil facility to convert it back into audio.
The cable is typically installed around the perimeter of the area to be covered but this is by no means the only method used. It is possible to design complex loops to meet particular requirements for example to ensure even field strength coverage throughout the reception area or low-spill loops to limit the radiation outside of the loop area either for security reasons or to prevent interference with other loops in adjacent rooms.
Where they are used
Public facilities such as halls, conference facilities, ticket offices and reception desks are often fitted with induction loop systems and a sign (as shown above) will indicate the presence of a system.
Since the Disability Discrimination Act:1995 was introduced many more induction loop facilities have been installed and it is fairly common technology although not always installed with the care and knowledge required.
Installation of loop systems
Loop systems should be installed to current technical standards to ensure that the system performs to an acceptable standard and this requires technical know-how, knowledge of the standards and the right equipment.
It will usually be necessary to conduct a site survey prior to designing the system to determine the physical constraints of the system e.g. the building construction, type of floor, presence of metal in the floor or ceiling as this will directly affect the design of the system, where the loop cables will be laid etc.
Testing
After the loop is installed the system will need to be commissioned and tested using a field strength meter and test receiver. Measurements should be taken at points throughout the loop area to check for even coverage and to identify any weak areas.
RK Sound Engineering design and install induction loop facilities to BS EN 60118-4:2006 or can upgrade, maintain or repair existing systems.
For a no obligation quotation contact us or call us on 01727 756999 to discuss your needs.