Woman behind a podium giving a speech in an auditorium

What is a Telecoil in a Hearing Aid?

What is a telecoil in a hearing aid? Telecoils are still effective in hearing aids today, even though they have been used for a long time. The main reason for this is that they combat one of the biggest complaints of hearing loss –  understanding speech in the presence of background noise. 

What is a Telecoil in a Hearing Aid?

A telecoil is a small copper wire wrapped around a rod and located in the hearing aid. It is added to the hearing aid to expand the functioning of the hearing system. The telecoil (sometimes referred to as “T-switch” or “T-coil”) is sensitive to magnetic fields and induces an electric current in the coil when it is in the presence of a magnetic field. Usually, a hearing aid microphone will pick up sound from the environment and amplify it. With a telecoil, however, it works as a small receiver that picks up signals, instead of the microphone, from a loop system that transmits an electromagnetic field. It then converts this electromagnetic field into a sound signal. The telecoil function must be activated either by manually adjusting the hearing aid (moving a switch to the “T” position) or by changing the program mode. However, newer hearing aid models can automatically switch from the microphone to the telecoil function when it detects an electromagnetic field. 

How does it work?

What is a telecoil in a hearing aid.

Telecoils were originally designed to work with telephones which have coils to amplify the signal. The phone can create a magnetic signal that transmits to the coil in the hearing aid, and the hearing aid will connect to the phone via these coils. When the connection occurs, the hearing aid will receive the signal from the phone, send it to the amplifier to be processed and amplified. It will then send it to the receiver where it will be delivered into the ear. This reduces the chance of having feedback when speaking on the phone compared to using the normal microphone on the hearing aid.

The telecoil functionality has since expanded to work with an “induction loop system”. An induction loop system is a big copper wire that is placed around the circumference of the room that creates an electromagnetic field. This magnetic field is picked up by the telecoil in the hearing aid and provides amplified sound to the user. If someone is speaking on a sound system in a room that has an induction loop system – you will hear them through the telecoil of your hearing aid, not the microphone. 

Where can you find telecoils?

Induction loop systems are commonly found in public spaces, as well as churches, concert halls, universities, and airports. They are even installed in some taxis.

If a loop system is available a sign will indicate its availability. For the loop system to work, you have to ensure that it is switched on and your hearing aid is on the telecoil setting.  

This is the symbol to look out for:

What are the advantages of a telecoil for hearing aids?

You might ask with technological advances, are telecoils still effective in today’s modern world? The answer is, yes! One must understand that hearing aids alone do not usually address all challenges that are created by hearing loss. A major complaint of hearing loss is understanding speech in the presence of background noise. This is particularly problematic in public venues that are characterized by background noise, reverberation, and a large distance between the speaker and listener. A huge advantage of a loop system is that only the sound source that is transmitted through the loop is received by the telecoil in the hearing aid, helping to minimize background noise and reverberation and to overcome distance issues.  Multiple studies have shown that a telecoil can make a significant difference in sound quality, compared to the standard hearing aid microphone and that patients are more satisfied with hearing aids when using a loop system. The majority of Behind-the-Ear (BTE) hearing aids have a built-in telecoil, where In-the-Ear (ITE) and In-the-Canal (ITC) hearing aids usually would not have a built-in telecoil due to their small size. 

What else is available?

Enhanced technology has led to the development of multiple assistive listening tools, such as Bluetooth, FM systems, and infrared technology. Bluetooth is fantastic in providing assistive listening when paired to a TV, portable music device, or a cell phone that is connected directly to the hearing aid. This, however, is less practical in a public setting, such as a cinema or even a large meeting room because all hearing aid users will first have to “pair” their hearing aid via Bluetooth in these different locations.

FM technology uses the signal from a transmitter microphone and converts it into an FM radio signal. This radio signal is then wirelessly transmitted from the transmitter to the receiver that is connected to the hearing aid. This signal can then be picked up by anyone with an FM receiver dialed into that frequency. It only needs a little installation and can be broadcasted over large distances and through walls.  Keep in mind that it is only useful if the information is not confidential as anyone can pick up this information from a distance.

Infrared technology uses an infrared signal (infrared light waves) to transmit sound. Infrared technology also requires only a little installation and can be configured to cover a large area. This requires a separate receiver to pick up the signal as it is not pre-fitted in the hearing, as opposed to the telecoil. It also cannot be used in all environments, daylight can interfere with the light signal, and this makes it not optimal for outdoors during the day. 

What are the shortfalls of telecoils?

Telecoils also have some shortfalls. Installing the wiring can be challenging when trying to fit it in an existing room, and the telecoil can pick up magnetic interferences from improperly installed wiring. This can present a buzzing noise in the hearing aid user’s ear. However, induction loops are the most user friendly as they are simple, discreet, and effective. Although induction loop systems are not available in all areas, they continue to gain popularity due to their simplicity and effectiveness. 

In conclusion, the telecoil is already installed in the majority of hearing aids and requires no frequency change or the need to pair to any device, and this makes it an effective assistive listening system that is practical, convenient, and reliable. Telecoils are therefore still recommended for most hearing aid users.

Image of post writer Lisa Brown.

Written by Lisa Brown

MA Audiology; B.Communication Pathology Audiology



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