You Were Asking. . .
Loop SystemsThe Best-Kept Secret in Town!
© March 2004 by Neil Bauman
Question: Every once in a while I hear hard of hearing people talking about “loop systems.” What are loop systems? How can they help mea hard of hearing personhear better? Are they expensive?D. B.
Answer: Good questions. Glad you asked them. Loop systems are truly wonderful. They let hard of hearing people hear ever so much better, especially in group settings where they can’t get close to the person speaking. For some reason, even though loop systems give wonderful sound and are cost effective, they seem to be one of the best-kept secrets around. Few hard of hearing people have even heard of them. Listen up. I’ll let you in on this nifty secret.
Loop systems are a class of Hearing Assistive Technology (HAT)/Assistive Listening Devices (ALDs) that work together with hearing aids to help hard of hearing people hear better. Other classes of ALDs include such things as Personal Amplifiers (PockeTalkers), FM systems and infrared systems. Unlike the above systems, you do not have to wear anything extra in order to connect to, and use, a loop systemno neckloops, wires, silhouettes, receivers or headphones. All you need are your hearing aids equipped with telecoils.
Loop Systems Can Do All This and More
Imagine being able to hear your TV or stereo from anywhere in your house as you move from room to roomand the sound stays exactly the samesounding as if a person is talking directly into both your ears at the same time. A home loop system can do this for you. Also, you can hook your home phones into your loop system so you can hear on any phone in the house with both ears, whether the phone is amplified or not. In fact, you can put any signal you want into a loop system. In addition to your phone, that may be your TV, radio, stereo, computer, door bell or whatever produces a sound you want to hear. You can even set up a portable loop system outside on the grass for an outdoor meeting or family gathering.
Did you ever dream of riding in your car and hearing the radio clearly without road noise intruding, or clearly hearing the people in the back seat? This dream can come true if you loop your car (or motor home or boat).
Do you wish you could go to a public meeting or church service and hear the speaker/minister as clearly as if he were talking right into your earsno matter where you are sittingwithout having to hook yourself to some ALD? Loop systems will do this too.
With loop systems you don’t have to fuss around, hooking yourself up with wires, neckloops, silhouettes or headsets to some ALD receiver. Furthermore, there is no extra paraphernalia to lug around, nor do you have to worry about batteries dying at the most inopportune times and not having fresh ones with you.
Furthermore, loop systems will accommodate as many people as can sit/stand inside the loopall without any extra equipment or cost. Therefore, with loop systems, you never have to worry about there not being enough receivers to go around.
Did you ever get to a meeting late and find all the chairs at the front were taken so you had to sit at the back where you couldn’t hear? If the room is looped, this is not a problemjust switch to your hearing aids to their telecoils and you will be able to hear loud and clear from the very back row.
You can use loop systems almost anywhere. Typically permanent loop systems may be installed in various meeting areas such as public buildings and churches. In Europe, they are now installed in many forms of public transportationtaxis, busses, trains and ships. Small systems can be installed at ticket counters, bank counters, etc. You will also find loop systems in some schools and offices where there are hard of hearing people.
Here’s Why Loop Systems Give Such Clear Sound
Loop systems provide wonderfully clear sound. This results in dramatically increased comprehension and increased listening pleasure. Loop systems broadcast personalized sound to both of your ears at the same time. Therefore, listening to a good loop system is like having the speaker talking right into both of your ears at the same time.
Speech is made up of various frequencies of sound. Basically, low frequency sounds give speech its volume while high frequency sounds give speech much of its intelligence. When you hear all frequencies properly, speech is clear and easy to understand.
However, as the distance between the speaker and your ears increases, a number of things happen to degrade this clear speech.
First, as the distance increases, the volume decreases so you can’t hear as well. At the same time, higher frequency sounds attenuate (get softer) with increasing distance and finally disappear altogether, leaving only lower frequency sounds. Without the high frequency sounds, speech is distorted and becomes difficult to understand. Speech is further distorted by reverberation (echoes) in roomsespecially those with high ceilings and/or hard surfaces. Finally, when there is a significant distance between you and the speaker, sounds around you mix with the speaker’s voice, burying his voice in a jumble of noise.
Loop systems address all these factors. First, sounds no longer get softer the further you are from the speaker. In fact, the volume stays pretty much constant anywhere inside the loop. Second, since the speaker is speaking into a microphone held about 3 or 4 inches from his mouth, high frequency sounds are not lost in the air. Thus, it sounds like the speaker is speaking right into both your ears. Third, reverberation is cut to a minimum as the sound of the speaker’s voice goes directly into the microphone rather than bouncing all around the room before reaching your ears. Finally, since the microphone is so close to the speaker’s lips, little extraneous sound gets into the sound system. Thus, the end result is clear speech.
How good are loop systems? I’m no stranger to loop systems so at a recent SHHH meeting, I decided to experiment a bit and find out. The speaker was using two microphones. One was hooked into the room’s public address system and the other was hooked into my portable loop system. Using my hearing aids’ microphones, I could hear the speaker fine as far as volume was concerned. However, the clarity of his speech was poor. Distance let the high frequencies fall off and that, coupled with the reverberation and echoes in the room, made understanding him difficult. In fact, I needed to speechread him in order to get his messageand I was sitting in the front row! When I walked to the back of the room, the reverberation and noise combined with the increased distance made understanding him even more difficult.
In contrast, when I switched my hearing aids to their telecoils, I could hear everything the speaker said loud and clear. It was so clear I didn’t even have to speechread. The difference was dramaticlike night and dayno matter where I stood in the room.
How Loop Systems Work
Loop systems consist of three basic partsa microphone or other input device, a loop amplifier and a loop of wire. That’s it for the transmitting side. Your own hearing aids equipped with telecoils make up the receiving side.
To set up a loop system, all you do is plug the loop amplifier into a wall socket, plug the input device or microphone into the loop amplifier, string a loop of wire around the perimeter of the room or area you want looped and connect the ends of the wire to the loop amplifier and turn it on. That’s it.
Audio signals are picked up by the microphone or directly from some sound source like your TV or stereo. They are amplified by the loop amplifier and then travel through a loop of wire that surrounds the listening area. The wire loop is used instead of regular loudspeakers. When the sound signal travels through the loop of wire, it produces a magnetic field in the looped area that mirrors the frequency and intensity characteristics of the original sound signal. At this point, the loop system’s job is done.
Now, it is your hearing aids’ job to convert this magnetic signal into sound you can hear. When you switch your hearing aid from its microphone to its telecoil, all you are doing is connecting a small coil of wire to the input of the hearing aid’s amplifier instead of its microphone. This tiny coil of wire is sensitive to nearby magnetic fields such as the one produced by the loop system. The changing magnetic field in the room loop induces a corresponding electrical signal into the telecoil. The hearing aid amplifier then amplifies this signal and you hear a faithful reproduction of the original speech signal.
This process of inducing an electrical current in one wire as a result of current flowing in a nearby wire is called inductionhence the term induction loop systemor just “loop system” for short.
Since any electrical current will result in a magnetic field, depending on their location, loop systems may be prone to interference. This interference is usually a buzzing or humming sound. This resulting buzz or hum may be so loud that you can’t use the loop system in certain places. Typically, interference can come from nearby electrical wires, fuse boxes, TVs, computer monitors and fluorescent light fixtures.
In order to tell if the area you want to loop is free from interference, all you need to do is switch on your telecoils, turn up the volume on your hearing aids and listen. If you hear loud buzzing, that is not a good place for a loop system. As you move around, you will notice that the interference level changes. Set up your loop system where the interference is non-existent or negligible.
Telecoils: The Other Half of the Loop System
The loop wire is the transmitting half of the loop system. The receiving half is the telecoils in your hearing aids.
What Are Telecoils?
A telecoil is just a tiny coil of wire inside your hearing aid that picks up electromagnetic signals given off by various devices including loop systems and telephone handsets.
There are a variety of names by which people refer to telecoils. They may call them T-coils, T-switches, telecoils, telephone coils or audio coils. It doesn’t matter. All refer to the same thinga tiny coil of wire in your hearing aid.
In order to use a loop system, you must have hearing aids equipped with telecoils. Unfortunately, a good number of hard of hearing people do not even know whether their hearing aids have telecoils installed or not. Before you buy a hearing aid, you should insist that it have good preamplified telecoils installed.
Telecoils got the name “T-switch” from the switch on the analog aids that typically switched between “M” for microphone, and “T” for telephone.
Ideally, your hearing aids should have a three position switch (for analog aids) or three programmable modes (for digital aids). These three modes are “M” for microphone only, “T” for telecoil only and “MT” for both microphone and telecoil together.
This combined microphone/telecoil mode is important. Here’s why. When you have your hearing aids in the “T” mode, you can only hear what comes through your telecoils. For example, if you are in a meeting and the person sitting next to you asks you a question, you won’t hear him at all. You’d have to switch your hearing aids back to the “M” setting and have the person repeat the question. In the meantime, you’ll be missing anything coming through the loop system.
With the “MT” position, you’ll be able to hear both through the loop system and people talking around you through your hearing aids’ microphones. This is a nice feature. For example, you may be listening to your TV at home though a loop system. If it is quiet and you have your hearing aids set to the “MT” position, you can listen for the baby crying or the doorbell or phone ringing at the same time you are hearing the TV.
Later, if there is a lot of noise around you (the kids are up making a racket near you), you can switch to the “T” position and cut out all this interference and just hear through the loop system. This way you can have the best of both worlds!
If you cannot get hearing aids equipped with a “MT” function, all is not lost. At home you can work around this by hooking both a microphone and a TV, for example, into your home loop system. The loop system’s microphone will pick up the kids crying, the doorbell ringing or any other sounds around you and superimpose these sounds on top of those from the TV and you will hear both though your hearing aids’ telecoils.
Orientation of Telecoils
Few people are aware that the orientation of your telecoils in your hearing aids is important. Normally, you just buy your hearing aids and never give a thought as to how the telecoils are physically installed in your hearing aids.
Orientation is important because maximum coupling occurs between two coils (for example, between a telecoil and a room loop) when both coils are oriented in the same plane as each other. Thus a horizontally-mounted telecoil works best when using the phone while a vertically-mounted telecoil works best when using a room loop or neckloop.
Often hearing aid manufacturers compromise and set the telecoils at an angle so they will work both with the phone and with room loopsbut this is done at the expense of optimum volume.
If there is a strong loop signal, this may not matter at allespecially if you have preamplified telecoils (telecoils with a tiny amplifier attached). However, if you are sitting where the signal is weaker, you may notice that you hear better with your head held at a certain angle. Experiment a bittilt your head at different angles and discover the best angle at which to hold your head for the strongest signal. In one looped meeting, I noticed that if I held my head up, I could hear well, but whenever I looked down to make some notes, the signal almost faded away.
Setting Up a Loop System
Setting up a portable loop at a meeting or gathering is easy. Just string the loop of wire around the roomand tape it down with masking tape or duct tape wherever people may walk so they won’t trip over it. Attach both ends of the loop wire to the loop amplifier. Plug a microphone into the loop amplifier and clip it on the speaker. Turn the amplifier on. Now anything the speaker says will be transmitted through the loop to anyone wearing hearing aids equipped with telecoils.
At home, you can run the wire loop around the edge of a roomstringing it over doorways or you can place it under the edge of a carpet. If you loop your whole house, the easy way to do this is to staple the loop around the edge of the ceiling in the basement. That way you will be able to hear anywhereboth on the main floor and in the basement.
Depending on the power of your loop amplifier, you can loop a room, several rooms or your whole house. That way you can move around in the looped area and still hear what you want to hear.
If you just want to loop your favorite chair (or car seat), setting up a personal loop system is as simple as putting a special loop pad under the cushion of your favorite chair or under the seat of your car and plugging it into the loop amplifier.
Getting a Loop System for Yourself
What does a home loop system cost? The good news is that home loop systems are relatively inexpensivein the neighborhood of $200.00.
Loop systems are especially nice whenever there are two or more hard of hearing people together. With a loop system, each person doesn’t need any extra equipment.
You could accomplish the same thing a loop system does with an FM system for example, but each person would need an FM receiver and a neckloop to connect the receiver to their hearing aids. With more than one person, this quickly gets expensive. The whole loop system only costs about 1/3 to 1/2 of what a basic FM system would cost for just one person, yet the loop system can handle as many people as you want to pack into the looped area at no extra cost.
There are several loop systems on the marketsome are big systems for large public buildings and others are small systems suitable for home and portable use. One of the best (or perhaps the very best) of these home systems is the Univox 2A. This is the system I use and like.
You can use the Univox system in your home using the supplied wall plug. For your car or other vehicle, just plug it into a cigarette lighter socket. Furthermore, you can use the Univox with a wire loop or a loop pad for personal listening (or both).
The Univox has three neat features. You can adjust the treble and bass characteristics of the loop to fit your particular hearing needs. Furthermore, you can control the power going into the loop to match any listening situation.
To learn more about the many features of the Univox 2A, or to order one for yourself, go to www.hearinglosshelp.com/univox2a.htm You do not have to continue to strain to hear. If you’re like me, once you have used a loop system, you’ll never want to go back to hearing with just your hearing aids alone.
Neil Bauman, Ph.D., was born with a severe hereditary hearing loss. He is a hearing loss coping skills specialist, researcher, author and speaker. He is not a medical doctor and does not prescribe/endorse treatment for medical problems. This educational article is for your information only. If you suspect that you have a medical problem related to your hearing, please seek competent medical help. Use the information here to help you make informed decisions, not as a substitute for any treatment that your doctor may prescribe. Send your questions to him at firstname.lastname@example.org or visit his web site at www.hearinglosshelp.com.
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