How do Hearing Aid Loop Systems and Telecoils Work?

Loop Systems

The first magnetic induction loop communication system was created by Joseph Poliakoff in 1937. The first wearable hearing aid that included a telecoil was the Multitine VMP in 1938. Induction loop usage became popular, but then declined after improvements were made to AM, FM and infrared technologies. Currently, loops are an economical way of strengthening the performance of hearing aids. 

How do Loop Systems Work?

Loop systems are composed of three parts: a microphone or another device that creates an electrical signal that you want to hear (for example a TV), a loop amplifier, and a loop wire. In some instances, the amplifier and the loop are placed in one single device (neck-loop or a silhouette). This is the side that controls the transmission. Your hearing aids that have the telecoils are the receiver. 

Audio signals that are gathered by the microphone or straight from the source of the sound, like your TV or stereo. The electrical option is intensified by the loop amplifier, which transmits through a loop wire that encloses the surrounding area. When the sound signal moves through the loop of the wire, a magnetic field is created in that loop area which imitates the frequencies of the original sound signal. 

Hearing aids convert sound signals into sounds that you can hear and comprehend. When changing your hearing aids from a microphone to the telecoil, it links the small coil of wire (t-coil) to the hearing aids’ amplifier rather than in the microphone. This tiny coil can easily pick up magnetic fields, like the one that is created by the loop system. The hearing aid amplifies the signal and you can hear a close reproduction of the original speech sound.
  
Induction is the method of inducing electrical currents in a wire that is the result of currents moving through a nearby wire. This is where the term induction loop system or simply “loop system” comes from. 

Telecoils
 
A telecoil is a very small coil of wire located inside of a hearing aid. It gathers electromagnetic signals from devices like loop systems and telephone handsets. 

The word telecoils has many monikers including T-coils, T-switches, telecoils, telephone coils or audio coils. 

A loop system usage requires hearing aids that have telecoils. Many who are hard of hearing are unaware if their hearing aids feature telecoils. Prior to making your hearing aid purchase, decide whether or not you want telecoils installed. Be aware that telecoils do use up space in the hearing aid, so they won’t be featured in the smaller hearing aid devices.

Hearing Aids that have Telecoils should have a Switch

In the U.S., there are no more 30 to 40 percent of current hearing aids that include telecoils. Telecoils only fit in the in-the-ear (ITE) and behind-the-ear (BTE) hearing aid styles. 

If your digital hearing aids feature a telecoil, there should be three programs that you can switch between. The three modes are “M” for microphone only, “T” for telecoil only, and “MT” for both the microphone and telecoil working at the same time. 

Hearing aids that are only switched in the “T” mode, only allows you to hear sounds that come through the telecoils. For example, if you are with a group of family members and the person seated next to you asks you a question, you will not be able to hear them at all. You would need to switch your hearing aids back to the “M” mode and the person would need to repeat themself. While in the “M” mode, you’ll miss any sounds that are being collected by the loop system.   

The “MT” mode allows you to hear through the loop system and other people who are speaking around you by using the microphones that are built into the hearing aids. You can listen to your TV with a loop system. If it’s very quiet and the hearing aids are set to the “MT” mode, you’ll be able to hear your phone ring while watching and listening to your TV.  

The “T” mode can be used when there’s a lot of commotion surrounding you. It blocks out all of the interference, so that you only hear sounds through the loop system. 

Tips on Telecoil Usage

While using telecoils, if you tilt your head as you hear a room loop the sound’s volume shifts. It may not matter if there is a strong loop signal, particularly with amplified telecoils. If you are seated in a space where the signal is weaker, you might notice that you hear better when your head is positioned at a certain angle. You may feel silly, as though you are treating your head like an antenna. Try tilting your head in different angles to find out which angle you should use for the best signal. 

You can do the same thing with a phone. Holding a phone up to your telecoils can affect how loud you can hear the person on the other end. Some hearing aid users need to position the ear-piece behind the ear instead of directly over the ear. This depends on what type of phone you use and where the telecoil is positioned in the hearing aids.

If you, or a loved one, are in need of hearing aids, please contact us at Pure Sound Hearing Aids for a free hearing test and consultation. 

Please be aware that Pure Sound services will only be available by appointment and for essential visits at this time. Essential visits include all appointments that require new hearing aid fittings, repairs and re-fittings. We ask that you please wait in your car, while wearing your mask, and place your hearing aids in a clean zip lock bag.  We will come to your car to get them. If you are having any problems with your hearing aids, or need supplies for your hearing aids, please call us before visiting one of our offices. 

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