Approved Document No. DAU0000050 Rev
2
• Page 4
Microphones
One microphone is
supplied with the DL50
and this is sufficient for
most applications. It is
normally positioned where
it will best pick up general
conversation and/or the
sound of telephones or
doorbells ringing.
Loop cable
The loop cable (supplied) should be run around the perimeter
of the room. It should be located at least 1.2 metres away
from the nearest hearing aid and is therefore best tucked under
the edge of the carpet or fixed to skirting boards or the ceiling.
Should you encounter a doorway, window or passageway,
run the cable up and over (using cable clips) or below the
obstruction but try to keep such deviations to a minimum.
Ensure that the cable is adequately protected from being
crushed in walkways and by furniture.
Audio input
Most televisions, DVD
players, etc, can be
connected to the DL50
using the SCART-to-Phono
lead supplied.
Amplifier location
The amplifier should be sited
as close as possible to the equipment
to which it is connected. Due
consideration should be given to
ensure any microphones you wish
to use have long enough leads to
reach the required sound source.
Planning the system
Careful planning of the induction loop system prior to installation is essential. Please refer
to the diagram below and the hints and tips section on the adjacent page to help avoid
poor performance and the need to re-position the amplifier or loop cable at a later stage.
A typical DL50 domestic loop system
Detailed connection
diagrams and system set-up
information can be found
later on in this manual.
Approved Document No. DAU0000050 Rev
2
• Page 9
When testing the installation, you may
hear a slight ‘humming’ noise in the
background, especially if using an
induction loop test receiver. This IS NOT a
fault with the induction loop system but a
common occurrence caused by mains
wiring. This hum will normally NOT be
heard by hearing aid users as most modern
hearing aids are equipped with built-in
filters which cancel this noise out.
Check that the loop strength meter
is not permanently lit red. The meter is
designed to light progressively from
1 to 3 (green to yellow to red) in line
with the loop signal strength. If it is
continually lit red, the signal will be
distorted and the amplifier may overheat.
If necessary, re-adjust the loop signal
control accordingly and re-test the sound
quality following steps 4 and 5.
8
Important note
Adjust the tone control to suit the user.
Turning the control clockwise usually
improves speech intelligibility and makes
the sound more ‘natural’. Turning it anti-
clockwise makes the sound ‘warmer’.
Large turns in either direction may lead to
you having to adjust the loop signal control
accordingly (see step 4).
TIP:
If the user is not present, plugging a set
of headphones into the amplifer’s socket
will indicate the effect of any adjustments.
6
If two microphones are used, more
emphasis can be given to one over the
other by turning the amplifier’s
microphone priority control clockwise or
anti-clockwise to suit. When the control is
in the centre position (its default setting),
equal emphasis is given to both
microphones.
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