How to Install a Hearing Loop

I have had a significant hearing loss for most of my life. It is a common affliction in my family. I purchased a pair of high-end digital hearing aids several years ago, but I have not worn them regularly. The main reason for not wearing my aids was that I often listen to recordings on an mp3 player using ear buds. It is difficult to use hearing aids while listening through ear buds. Recently my hearing loss has begun to severely impact my ability to interact with friends. I decided that I should find a way to wear my hearing aids and still be able to listen to recordings on my mp3 player.

My answer was to utilize the telecoil that is built into most modern hearing aids, including mine. Usually one needs to switch between telecoil and the microphone input. Telecoils were originally developed to magnetically transmit the audio from telephones to hearing aids. In Europe, and more recently in the US, the audio system in many churches, meeting places, theaters, etc., have been equipped with loop antennas that transmit to telecoils. These setups are commonly called hearing loops. (See, e.g., http://www.hearingloop.org/) For basic info about telecoils, see:

http://hearingloss.org/sites/default/files/docs/HLAA_Telecoil_Brochure_0.pdf

I decided that, as part of my solution, I would install a hearing loop in my living room to transmit the TV and stereo audio directly to my hearing aids. My hearing loop system consists of a loop of copper wire around the perimeter of the room, which isconnected to a loop amplifier. The amplifier is, in turn, connected to the speaker connectors on my stereo receiver and to 120 VAC power.

List of Materials:

Loop America LAD15 Loop Amplifier (purchased from loopamerica.com)

~120 ft 22AWG insulated, stranded copper wire (purchased on Ebay)

1 pair of 3’ speaker leads with male RCA adapter plugs (purchased from gpsmart on Ebay)

I chose the LAD15, because it was the lowest priced amplifier I could find that I thought would do the job. A search on the Internet identified several alternative amplifiers. I used the 22-gage wire because I had lots left over from another project. Terry at Loop America recommended 18-gage wire, but he thought the 22-gage wire would work. (It seems to work fine.) The LAD15 requires input leads with male RCA plugs. My stereo receiver needs leads with bare ends. The folks at gpsmart were incredibly cooperative in providing high quality leads of the correct length.

List of Tools:

wire pusher (home made tool)

putty knife

My living room is carpeted. My plan was to use the pusher to shove the wire along the edges of the room down between the carpet and the baseboard. I made the wire-pusher tool from a piece of 12AWG copper wire by

1. Stripping off an inch, or so, of insulation

2. Grinding the end of the wire flat, and

3. Filing a small groove in the end of the wire, as shown in the photo:

It took a couple of hours to install the loop. First I laid the wire on the carpet around the perimeter of the room.

Starting close to the planned amplifier location, I pushed the wire beneath the baseboard, and then just worked my way all around the room. It just took patience. I had to push down small segments, say ~2”, at a time. Larger segments would be loose and would pop back out. Be sure to leave enough wire at the start to connect to the amplifier.

I used a putty knife and the pusher to get the wire beneath the metal strip at the junction between the kitchen vinyl flooring and the carpet.

The wire does not want to stay below the carpet where the carpet abuts the hardwood flooring of the entryway. I may dry a few droplets of a rubbery glue, e.g., Amazing Goop, around the wire to see if they will help keep wire in place.

When I got back to the starting point, I ran both ends of the wire loosely through a 1/8”x1” piece of shrinkwrap tubing to complete the loop.

Then, connect the two ends of the loop to the output connectors on the amplifier.

Next, connect the audio source to the RCA Plug speaker leads and plug the leads into the amplifier.

Finally, plug the amplifier power supply into a 110 VAC outlet and plug the power supply cable into the amplifier.

.

Turn on the amplifier and enjoy the interference-free sound.

I was concerned that the metal strip at the kitchen entry might cause a gap in the electromagnetic field created by the loop, but it does not seem to cause any problem. I was also worried about a place along one wall where coax cables carry the satellite TV signal. Again, there is no noticeable degradation of the signal in that area of the room.

I have only noticed two problems with the system:

1. My hearing aids lack a volume control. Sometimes the telecoil transmitted sound is so loud that it is uncomfortable. My only recourse is to turn down the LAD15 power setting.

2. Our old TV produces electromagnetic emissions that are picked up by my hearing aid telecoils, if I am very close to the TV. A separation of 4 or 5’ is enough to eliminate the interference.

One nice plus is that the hearing loop signal penetrates through the floor of our wood-frame home, and the telecoil signal is actually stronger in the basement below the living room than it is in the living room.

Now that the installation is done, the last thing is to put up the hearing loop logo :-)

Installing the hearing loop, alas, does not address my problem with ear buds. However, telecoils are still part of the solution. Several firms market devices that replace ear buds with small telecoil transmitters. I’m trying two: Music Link from tecear.com and the Inductive Loop from Conversor (via amazon.com). The Music Link transmits wonderfully to my hearing aids. The Inductive Loop also works well, but it is monaural, so stereo recording channels are blended together. Time will tell which is more convenient to use.

There is an alternative solution to the ear bud problem that does not involve telecoils. “Audio shoes” are available for my hearing aids. They are small adapters that snap onto the bottom of my behind-the-ear aids. The shoe has an outlet for a tiny 3-wire connector. Leads are available that connect the shoes to a sound source. The shoes work, but are less convenient and more expensive than the Music Links or Inductive Loop. I've given up on the shoes because my fingers are not small and coordinated enough to reinstall a contact cover that is peculiar to my aids.

Progress Report, 11/30/14

The hearing loop continues to function perfectly. The biggest disadvantage of my loop-telecoil system relative to my Sennheiser TR120 wireless headphones is that the phones have a built-in volume control, so one can adjust the volume on the fly to compensate for changing background noise. One other advantage of the phones is that they work outside the loop, e.g., in my yard or garage. The primary advantage of the loop-telecoil is that I'm wearing my hearing aids, so I understand conversations better if I switch the aids from telecoil to microphone.