There are two basic components.
Firstly. the loop itself - a thin wire which runs around the
perimeter of the area where the hearing aid listeners will
The wire must be run on a level
plane in order to generate the required magnetic field and
can be under the flooring or above the doors. It doesn't
need to go around the whole room, just the area where the
people needing to hear usually sit or stand. E.g. it doesn't
have to go around the whole of a Church, just the area where
the Pews are and perhaps also the Font.
The loop plugs into the second
component, a 'loop amplifier'.
Microphones can be plugged directly
into the loop amplifier or you can take a feed directly out
from your PA system via the PA's aux out socket. This is the
best way to get the right balance between people listening
directly to the PA and using their hearing aids.
When in use, the hearing aids are
simply switched to the 'T' setting and the users hear both
speech and music with crystal clarity, as though they were
wearing headphones plugged in to a Hi Fi system.
Smaller loops are available for
office or desk situations, and personal loops are also
available for a person to wear around their neck.
See some of the range available in
the online shop >>
More detailed information
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.
As a quick reference, refer to the table below.
Cable CSA (mm sq) / Total Loop Length
1.0 / 60m max.
1.5 / 110m max.
2.5 / 200m max.
4.0 / Over 200m
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 (if present) will enable multiple
loops to be used together.
Further installation advice is
available in the product manual.
If you need a Hearing Loop
system please give us a call on 01375 892317 or email
firstname.lastname@example.org as not all products are shown
on our website at present.