Copper foil tapes, available in 3 widths, intended for induction loop systems where the loop has to pass under carpets or be located where conventional cable is unsuitable. To make corners, the tape can be simply folded across itself.
The wire for these hearing loop systems should be installed in a loop, covering the area in which it's needed. For example, in a church, the loop needs to surround the area of the pews and font but isn't needed throughout the whole church.
Prior to installation, it is important to check if there will be any equipment in the vicinity that may interfere with the loop’s magnetic field, such as large transformers, high power cables or substations. It is also important to ensure that no equipment will be adversely affected by the loop field, such as sensitive data or signal cables. In these cases, it may not be possible to cover some or any of the required area with an induction loop.
The cable gauge will depend upon the total length of the induction loop. Usually, the loop will be installed around the perimeter of the listening area. However, there are various techniques which can be employed to build arrays to vary the shape and strength of the field. In general, calculations outlined here are based upon a perimeter installation.It is recommended to use good quality insulated pure copper cable for the induction loop.
The cable gauge used will need to be determined by the total length of the cable run. The LA-series loop amplifiers are designed to operate with a load of between 0.2Ω and 2Ω.
Total loop length 60m max = Cable width 1mm2
Total loop length 1100m max = Cable width 1.5mm2
Total loop length 200m max = Cable width 2.5mm2
The wire may be run in plastic conduit but not in any metal containment so as not to impair the magnetic flux.
The ideal height to install the cable depends upon the width of the loop (i.e. the narrowest dimension relative to the listener). The optimum output will be achieved if the cable is installed 14% of the loop width higher or lower than the plane of listening (ear height). In practical terms, the loop is usually installed onto skirting boards, under flooring or at ceiling height so that it is unobtrusive.
It is recommended to avoid varying height levels as much as possible to avoid anomalies in field strength. For irregular shaped areas or larger than the loop amplifier’s capacity, multiple induction loops may be required for coverage. Connecting further loop amplifiers using the Slave connection will enable multiple loops to be used together.