headphone to telecoil review: Music Link vs HATIS EPIC bakeoff

Giganews Newsgroups
Subject: headphone to telecoil review: Music Link vs HATIS EPIC bakeoff
Posted by:  zafd…@yahoo.com
Date: Mon, 6 Oct 2008

I=92ve used Music Links for a year or two.  I=92ve only had the HATIS for
a few days, but feel confident on the following comparison.  If there
are others comparable devices to these, post them here, maybe I=92ll
give them a try next time I have money burning a holde in my pocket.

Executive summary, The HATIS work very well, the music links are OK,
with a small DIY modification they should be much improved. If you=92re
short on coin, you might try the music link mod, or even build you own
(at the bottom).

The Music Links are tiny.  Imagine 75mm of wire coat hanger bent into
a hook that hangs on your ear.  The coupling coil is very small in
diameter and is fully contained in the diameter of the hook.  They are
also very light.  When ideally positioned against a BTE coupling is
good to excellent.  The problem is that they are so small and light
they are difficult to keep in the optimal location.  If they pivot
even a 5 or 10 mm coupling will be reduced, often significantly, the
sound will become greatly diminished (or even be gone completely).  If
you are other then sitting with your head still, you can bet sooner or
later, you will be reaching to your ear to reposition the Music
Links.  The hook design does not keep the coil aligned to the hearing
aid and as a result you find getting them placed optimally is more
then just hooking them on the ear, you will need to move them around
until you hit the =91sweet spot=92.  Since the Music Links are so
sensitive to placement, there will be variability as well with the BTE
being used (they may work better or worse for you).

The HATIS are big compared to the music links.  Imaging a very large
BTE squashed down to ~4mm thick and that=92s the size of the HATIS.
Like the Music Links, they hook on the ear but since it is shaped like
a BTE,  so it sits right next to your instrument and cannot cower
around the back of the ear like the music links.  I have=92nt taken them
apart, but it certainly looks like they coil is laid out in the
opposite direction of the music links.  For you Maxell fans, this puts
the field directly through the BTE.  The result is the coupling is
better when anecdotally placed compared to an optimally placed Music
Link.  In fact I am surprised the telecoils can even sound to good!
The HATIS tends not to move around as much as the music links due to
their size and weight, I suspect they would even be OK for a running.
While they are large, I am able to wear them comfortably even while
wearing eyeglasses (my BTE is an America Hears Freedom, which is a
very large instrument).  If you are already tight behind the ear, the
HATIS may be a problem where the Music Link will fit without a problem
in the tightest space.

Secondary items:
The HATIS has to be run =91inboard=92 or =91outboard=92 of the BTE due to i=
t=92s
design, I find both work equally well.  Running it outboard makes it
more difficult to get at the adjustments on the instrument and also
make it more visible.  The ML are small and move around enough you
don=92t even know weather they are inboard or outboard at any one time.
In fact the way they stay in place best is to place the hook across
the earhook of the BTE rather then over the ear itself.  On my large
instruments, this reduces coupling, but may work well for smaller
instruments.

The HATIS has beefy overmolded strain reliefs where the wire goes into
the earpiece or headphone jack.  The music link has no such strain
relief on the earpiece.  I did have my music link =91disemboweled=92 when
my dog jumped up on me and the coil was ripped out of the hook.  The
overmold on the HATIS looks beefy enough that it would have been
intact (then again, my ear would be the loser here!).  The wire used
on the HATIS is stiffer and thicker, making it harder to coil and put
away. When it is uncoiled, it tends to keep its coiled shape somewhat,
making it harder to manage.  The Music Links use a thinner wire and
the insulation is more rubbery, it coils and stores nicely.  The
length of the cord on the music links is adequate for most use; about
3=92.  When I use my cargo pants and put my ipod in the lower pocket,
this is too short though.  The HATIS cord is around 5=92; longer then
you should ever need.  The longer length and stiffer wire make the
coiling and storage of the HATIS the only area where the Music Links
have a big advantage.

If you=92re not concerned what they look like, you might try one of the
following DIY projects.

Easy DIY Project (Music Link mod)
Now that I have tried both, I think the Music links could be easily be
improved as a DIY project just by building a widget to position it
better.  Before I got the HATIS I was thinking of trying to build a
clip for them to keep them on the instrument optimally.  Now that I
see how well the HATIS stays put due to it=92s size and weighting, there
should be no reason the Music Link could not be likewise positioned.
Position the Music Link optimally and have someone take a photo of
where it rests on your instrument.  Now your job is to get the ML
attached to something that will hang off your ear and naturally be in
this location.  Hot melt it to a cleverly cut piece or plastic, imbed
it in modeling clay so it fits perfectly against your ears, there are
probably many other options.  I suspect this will improve the ML
significantly, but I think the HATIS will still have the edge due to
the orientation of the coil.

Hard DIY Project (Roll your own)
You may think these devices are some high tech magic based on their
high prices.  Nope.  They=92re simply coils of wire encased in plastic,
one for each ear.  If you have the time and patience, you should be
able to make one for scratch.  The toughest part will be winding the
coils.  You will need hundreds of turns of fine wire.  They do make
special wire for this called magnet wire, but finding someone to sell
you a few hundred feet may be tough.  If you=92re interested in doing
this, read up on DIY coil winding.  Don=92t worry so much about the coil
inductance, but shoot for about 25 ohms for each of the coils.  You
may be able to get creative and use a sewing machine bobbin winder to
help you wind the coil.  Wind the coil on a bobbin that will allow you
to form the coil such that the windings on the coil roughly trace the
perimeter of your instrument.  Once the coil is formed, epoxy or
otherwise immobilize the wires or it will surely become a tangled mess
in no time.  BTW, if the wire breaks or you get a single point where
the wires short to each other in the coil, the whole coil is useless.
Build a widget that will hold the coil such that the coil when hanging
on your ear traces the perimeter of your instrument, cut the speakers
off an old set of headphones & connect.  You should have something
comparable to the HATIS.

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