|
Andrew
Stewart has been installing loop systems for 20
years. He is hearing impaired and has two hearing
impaired children – all use a loop to watch
TV at home. Andrew helps us to unravel the mysteries
of loops.
What is a loop?
An AUDIO INDUCTION
LOOP SYSTEM consists of a microphone (or TV etc), a special amplifier
and, in the place of a speaker, a loop of wire placed around the room.
Sound waves from the speaker's voice going into the microphone (or the
TV signal) is changed into an electric current, amplified, and then sent
through the loop, which emits a magnetic field in the room. The field
is picked up by the "T" switch of a hearing aid, amplified,
and converted back into sound. Hearing aid users sitting within the loop
system can pick up the speaker's voice or TV without distortion and no
background noise, simply by turning on the "T" switch on their
aids. The loop is fully adaptable to television, radio, stereo, tape recorder
or movie projector.
Why would parents install
a loop in their home?
Most people think
that hearing aids are perfect (especially some professionals). They think
that once a person has hearing aids, all their hearing difficulties are
solved. What the hearing aid does is pick up all the sounds. This enables
the hearing aid user to hear all the sounds around them, and solves the
problem of volume.
However, the ear of
a hearing impaired person has lost the ability to "focus" on
a sound. For example, in a noisy room hearing people can focus on the
one person they are trying to hear, even though the background noise can
be nearly deafening (pun intended)!
The hearing aid cannot
provide that focus (although directional microphones do help).
In a room that has
no background noise, hearing is still a problem. When I talk to someone
face to face, I can hear and understand them very well with my hearing
aids (normally).
If I then stand 10
feet away, I can still hear them, as my hearing aids give me volume, but
I struggle to understand the words. The words sound mumbled, and turning
my hearing aids up only makes the mumble louder.
The reason for this
is that when someone talks from 10 feet (or more) away, their voice bounces
of the walls, floor, furniture etc, and blurs the sound. Hearing people
can differentiate the direct sound from the reflections, whereas hearing
impaired people struggle.
To overcome this problem,
I either have to move closer to the sound source, such as the person speaking
or the TV or radio or I can put a loop or FM on the person speaking or
the TV or radio.
The result of this
is that my hearing aid receives direct sound without any reflections,
and is giving the hearing aid the best possible signal with which to work.
A lot of hearing impaired
people don't know what they are missing out on until they try it. I have
had some kids come round and try the loop at my home and I see their face
light up.
Also, the clearer
a child can hear, the more he/she can focus on what they are hearing,
rather than on trying to hear. This means that more is taken in, and literacy
can also improve as a result.
What are the differences
between a loop and an FM system?
When correctly supplied
and installed, the loop and the FM are almost identical, except using
the microphone on the FM or a microphone with the loop amp may pick up
some background noise. A direct connection from either of the Loop or
FM is definitely preferred.
The main difference
between the two is the way in which it is used. With the loop system my
kids (and I) can sit almost anywhere in the room. I simply switch the
telecoil (T switch) on my hearing aid on, and hear the TV. We don't have
any of the battery or maintenance issues as with the FM. Also, and most
importantly, the kids can feel "normal". They don't have to
wear an extra device to hear the TV.
Are there other advantages?
In some cases, connecting
to the ‘audio out’ on the TV means that we can turn the sound
off on the TV and it still comes through the loop. So, I often turn the
sound off when I get home from work so my wife and I can talk, without
the TV blaring, and my children keep listening on the loop. Certainly
for me, without the loop I have to ask my wife to repeat a lot, which
drives her up the wall. With the loop it is so clear, and we can both
just sit back and enjoy the program.
With the loop I have,
I also get an alarm tone when the phone rings, and a different alarm when
the doorbell goes. This is necessary for older kids and adults, because
when on the T switch, the microphone on the hearing aid is switched off,
providing crystal clear sound but this does mean that you cannot hear
other sounds around you.
Who can benefit from a loop?
Hearing aid and cochlear implant users with a
T switch can use a loop.
Any problems?
• Interference - I normally resolve that issue when I do an installation.
Many people think that interference comes from fluorescent
lighting but the problem comes from the power cabling, particularly if
there are two - way switches for the lights. The
best way to monitor loops is with a loop receiver. Unfortunately, the
reasonable units are $290.00. Basically, the person putting the loop in
should identify the presence of interference and where to avoid, or resolve
it.
• I should
also mention, that connecting the loop or the FM to the audio out on TV
doesn't always work with videos. It is a case of try and see. In these
cases the only option is for the microphone for the FM or loop to be ‘blu-tack’ed
in front of the speaker.
• Cinemas -
loops in only some of them work. You need to make sure you find out which
seats are covered by the loop.
Where can you purchase a loop for your home?
Loop systems cost
between $290 and $405. (Depending on type of floor – wood or concrete,
and size of area).
The loop amplifier is totally portable. I recommend that the loop cable
be installed permanently. The roll of cable costs around $40 and I recommend
that new cable is laid if you move home.
The following organisations
sell different home loop systems:-
Printacall
Deafness Resources Australia
WA Electronics
Word of Mouth Technology
For further enquiries,
contact Andrew Stewart (Technical Manager) at Printacall
Ph: (02) 9809 2392 TTY: (02) 9809 1283 Fax: (02) 9809 2345
Email: astewart@printacall.com.au
|
