WELCOME TO THE INDUCTION LOOP PAGE
Induction loops are a mystery to many people including architects, designers and electrical contractors who regularly seem not to understand the concept and bravely go ahead and specify perimeter loops - usually in the ceiling space, in adjacent or vertically stacked rooms. Later when the client tries to use these facilities there are major problems with overspill from room to room. Often the requirement will be to install the loop approximately 1 metre in from the wall "to reduce the overspill". This is not a solution that will work satisfactorily, if at all. Sadly by this time the client has spent good money on systems that are not fit for purpose, and to rectify the problem is even more costly as it will require proper loop designs (see the photograph below) and the removal of furniture and the full floor covering back to the original, and a clinically clean floor surface. The client will also need additional equipment to make it work. The only other solution as a retro-fit would be to go down the infrared route which is quicker to install, but the equipment is considerably more expensive and will still need the microphone and audio inputs as necessary.
The equipment required for a single room low spill loop* would be a pair of loop amplifiers with a phase correction unit and of course the audio source. In most types of meeting rooms this would normally be a boundary type microphone installed in an appropriate position, possibly in the ceiling, and depending on the requirements maybe an additional audio source from a laptop PC or a data projector.
The advantages of a loop over an infrared system is that the loop can/should remain on at all times so that anyone needing the loop facilities will be able to make use of the facilities just by turning their hearing aid to the "T" position. An infrared system should also be on at all times, but the user will need to obtain a neck loop listener/IR receiver from an administrator as these items are rarely left on charge in the relevant rooms due to their high value and the likelihood of the user forgetting to return it after use.
The above loop system was installed in conjunction with ScanAudio Ltd and is a complex three-room arrangement as the dividers can be clearly seen. This photograph shows only one of the dividing sections completed with the section further back yet to be filled in. This system comprised of 10 loop amplifiers, 1 pair per room area and a pair of amplifiers for each of the divider in-fill loops. Because of the complex design, each room loop would cut off at the divider, but when the rooms were opened up there would have been completely dead areas aproximately 1m wide and across the room at each divider position. A switching arrangement was configured to allow the rooms to operate in total isolation or in various combinations.
To date PA Hire & Install in conjunction with ScanAudio Ltd are the only installers to undertake phased array loops on both floors and ceilings in a three floor installation in Daventry for the Salvation Army where each floor could select which system to use depending on the program content from adjacent floors.
So, if in doubt seek advice before specifying a basic induction loop - it may not be appropriate!
*A single room low spill loop is in fact an array of two loops of flat copper tape that follow a pattern specific to the design of the room and laid out using a laser to precise measurements, and hence the need for two amplifiers per room.
Via the Contact Us page or on