What Is An Induction Loop And How Does It Help Hearing Aids?


One of the most fascinating aspects of hearing aids is that they are often exceptionally complex, but many elements of how they function are both deceptively simple and highly effective, as well as being small enough to fit in a form factor that is practically invisible.

The best example is the T-switch setting on hearing aids, used to listen to an audio induction loop or hearing loop frequency. It is a standard feature on almost every hearing aid you can buy in the United Kingdom, as it allows for clear audio, something often required for giving and receiving instructions.

Most people with hearing aids know about them and know to switch to either the T or MT setting when in a taxi, a post office, certain parts of a train station or at the vast majority of churches, as well as many other buildings as a reasonable adjustment required by the Equality Act 2010.

However, to understand how they can benefit you, it is important to understand how they work and where they came from, as well as why the induction loop setting is marked with a “T”.


How Does An Induction Loop Work?

An induction loop works through two interesting and surprisingly simple technologies.

The first is the physical loop of electric cable, which circles a particular designated area (either a room or a part of a building. This loop generates a small electromagnetic field that works effectively as an amplifier for sound when linked to the second part of the technology.

A hearing aid fitted with a compatible pickup coil then picks up the electromagnetic field directly, allowing for specific sources of sound to be delivered to the ear directly.

This allows for a hard-of-hearing person to more clearly hear an announcement, music concert, event, member of the court or delegate of a meeting without the effects of interference or background noise getting in the way.

This makes it easier, more comfortable and less frustrating to hear vital pieces of communication and respond accordingly, making everyday life far easier as a result.

The original form of the induction loop was known as the telecoil or T-coil, which is the reason why hearing aids to this day mark the induction loop with a “T”.

It was invented by Joseph Poliakoff and his Multitone Electric Company initially as a way to pick up the magnetic field generated by telephone coils, designed to make it easier for people using hearing aids to hear a telephone conversation without a lot of feedback and background noise.

This concept had expanded by 1937, when the first magnetic induction loop was patented, and dispensed with the need to speak to someone through a telephone, instead delivering sound directly through the electromagnetic field.

It is the primary type of assistive listening technology in the UK, although in the United States, a competing “neck loop” system that used FM radio waves to deliver audio became more popular, albeit less convenient for users. An infrared system is also used in cases where an induction loop is impractical.