Hearing loop (or induction loop) systems use electromagnetic energy to transmit sound. A hearing loop system involves four parts:
- A sound source, such as a public address system, microphone, or home TV or telephone
- An amplifier
- A thin loop of wire that encircles a room or branches out beneath carpeting
- A receiver worn in the ears or as a headset
Amplified sound travels through the loop and creates an electromagnetic field that is picked up directly by a hearing loop receiver or a telecoil (see sidebar), a miniature wireless receiver that is built into many hearing aids and cochlear implants. To pick up the signal, a listener must be wearing the receiver and be within or near the loop. Because the sound is picked up directly by the receiver, the sound is much clearer, without as much of the competing background noise associated with many listening environments.
Some assistive loop systems are portable, making it possible for people with hearing loss to improve their listening environments, as needed, as they proceed with their daily activities. A hearing loop can be connected to a public address system, a television, or any other audio source. For those who don’t have hearing aids with embedded telecoils, portable loop receivers are also available.