Infrared systems use light waves to carry sound. Transmitters flood the space with invisible IR light and users pick up an audio signal using an IR receiver.
These systems are ideal for venues where confidentiality is important as the sound waves can’t travel through doors, walls or glass. IR systems are also perfect for venues where users move between rooms that have different sound sources.
Radio frequency systems use wireless radio waves to transmit sound. Users listen to the sound through a receiver unit with headphones or, if they wear a hearing aid, through an inductive neck loop.
Unlike IR systems, RF signals can be transmitted through walls, glass partitions, ceilings or other obstacles. They can be used in:
Clear barriers installed for infection control or security can cut sound levels by up to 15db.
Window intercoms transfer speech from one side of the partition to the other, removing the need for raised voices. These are especially important in settings like hospitals or banks, where confidentiality needs to be maintained.
There are other assistive listening technologies being developed, such as Bluetooth, but these are some way from being considered in the same light as the options above.
The International hearing Loop Manufacturers Association (IHLMA) has a complete guide to assistive listening technologies, available to download from its website.