Hearing loop vs FM, infrared and Auracast: which assistive listening system fits

Every assistive listening system carries a clean feed from the sound system to listeners who struggle with distance, noise and reverberation. They differ in who can use them without borrowing anything, how far the signal travels and what the venue has to look after. This guide compares them from the installer's side.

Key points

• A telecoil user needs nothing extra in a looped room: they switch their hearing aid or cochlear implant processor to T.
• FM and infrared need a receiver for each listener; telecoil users can wear it with a neckloop.
• Auracast™ broadcast audio reaches listeners' own devices: hearing aids and implant processors with Auracast, and supported phones with LE Audio earbuds. Others borrow a receiver.
• Infrared stays inside the walls. A loop's field reaches past the wire, and the layout can limit how far. Radio, Auracast included, passes through walls.
• Many rooms are best served by a loop and Auracast fed from the same mix.

Four systems side by side

The biggest practical difference is what the listener has to do. A telecoil user presses one button. An Auracast listener picks the broadcast in a phone menu or hearing aid app. Everyone else asks staff for a receiver, so someone has to keep a charged, clean set ready.

Hearing loops

A loop driver sends the audio as a current through wire or copper tape around or under the listening area. The magnetic field it creates reaches the telecoil in a hearing aid or cochlear implant processor directly, without room noise or reverberation and with essentially no delay. Listeners without a telecoil can use a loop receiver. What is a hearing loop and how does it work? covers the parts.

The design work is in the field. It weakens with distance from the wire, sags in the middle of wide rooms and loses strength and treble over steel. Phased arrays and an allowance for metal loss handle most of that; the step-by-step design method walks through each choice. The field also reaches past the wire, which matters next to another looped room or a confidential space (see hearing loop overspill).

Loops have a long-established performance standard, IEC 60118-4, with targets for field strength at listening height, how evenly it covers the listening area, frequency response and background magnetic noise. Each can be measured and recorded at handover (see Commissioning a hearing loop). Hearing Loop Designer helps at the planning stage: it models the field at listening height and checks the design against IEC 60118-4 field-strength and frequency-response targets, metal loss included, before any wire goes down. Installed performance is confirmed by commissioning.

Limits to plan around: not every hearing aid has a telecoil, some listeners have never had theirs switched on, and the wire or tape needs a route under carpet, in the floor or in a ceiling.

FM and other radio systems

A radio transmitter takes a feed from the sound system, and listeners borrow receivers with headphones, or with a neckloop if they use a telecoil. FM is usually the simplest system to install, and its range suits large halls, outdoor events and tours.

The venue keeps a receiver fleet to charge, clean, lend and collect. Radio passes through walls, so anyone nearby with a receiver on the channel can listen, and neighboring systems need separate channels. Other radio sources can interfere.

Infrared

Emitters fill the room with invisible light, and receivers turn it back into sound. Walls stop the light, so infrared suits courtrooms, boardrooms and other rooms where the program has to stay put. Several channels can run at once, which suits interpretation.

Infrared needs the receiver to see an emitter, directly or by reflection off light-colored surfaces. A receiver in a pocket, or a listener turned away from the emitters, can lose the signal, and bright sunlight can swamp it. Balconies and the seats under them often need extra emitters, and uncovered windows let the light out. As with FM, each listener needs a receiver.

Auracast broadcast audio

Auracast is Bluetooth LE Audio broadcast at 2.4 GHz. A transmitter fed from the sound system sends one or more streams, such as the main program and a second language. Listeners join with Auracast hearing aids or implant processors, or a supported phone and LE Audio earbuds; others borrow a receiver, with a neckloop for telecoil users. Bluetooth SIG rules have public transmitters send at least one Standard Quality stream, a format every Auracast receiver, hearing aids included, can play.

A broadcast can be open, or closed with a code that listeners enter before they can hear it. The signal still passes through walls: the code protects the content, not the signal.

Limits today: phone and hearing aid support is still growing, joining takes a menu or app step, the sound arrives a few tens of milliseconds late, and walls, bodies and a busy 2.4 GHz band shape coverage, so placement needs planning and a walk test. Loops have IEC 60118-4; the matching IEC performance standard for 2.4 GHz audio streaming to hearing aids, IEC 60118-17, is still in preparation, with publication forecast for late 2027. BroadcastPlan Pro, our sister product, is planning software for Auracast broadcast audio.

Delay: a worked example

Example, with assumed numbers: in Community Hall a listener sits 14 m (about 46 ft) from the front loudspeakers. Sound travels about 343 m/s, so the room sound reaches that seat roughly 41 ms after it leaves the loudspeakers.

• The loop signal arrives essentially at once, about 41 ms ahead of the room sound.
• Suppose the Auracast stream arrives 40 ms after the audio leaves the mixer. The real figure depends on the transmitter, its settings and the listener's device. In that seat it lines up with the room sound; nearer the front it lags, further back it leads.
• Some transmitters can also flag a stream so that receivers which support the flag play it sooner. It is meant for rooms where the stream would otherwise arrive after the room sound.
• Feed either system from after the delay that time-aligns rear loudspeakers, and that delay is added for every listener.

So take both feeds from an output with no loudspeaker delay.

Pairing a loop with Auracast

Running both from the same feed serves telecoil users and personal-device users at once. HLAA advises hearing aid and cochlear implant users to make sure their devices have both Auracast and a telecoil, and expects existing systems such as loops to stay in use for some time.

1. Build one assistive listening mix: speech-forward, steady in level, without the reverb and effects meant for the room.
2. Split it to the loop driver and the Auracast transmitter, from an output with no loudspeaker delay.
3. Set each input level on its own: the loop for field strength, the transmitter for its stream level.
4. Sign both: the loop symbol with a T, and the broadcast name (and code, if closed).
5. Commission both: measure the loop against IEC 60118-4 targets at listening height, walk-test the broadcast with several types of device, and hand over one record.
6. Keep loan receivers for listeners with neither a telecoil nor an Auracast device.

Example: choosing for Community Hall

Community Hall, a synthetic example, has a 300-seat main hall, a meeting room next door used for private meetings, and a lobby where latecomers wait.

• Main hall: a loop for the seating, designed at seated listening height (1.2 m) and laid out to limit the field in the meeting room, plus Auracast from the same mix, with the transmitter placed so coverage includes the lobby.
• Meeting room: a second loop means planning both layouts so that each loop is heard as little as possible in the other room. For confidential meetings, infrared stays inside the walls; a closed Auracast broadcast protects the content but not the signal. Test from the hall side either way.
• Receivers: a small loan kit with headphones and neckloops.

Accessibility rules where the venue is located set receiver numbers, signs and other details, so check them on each project.

Hearing Loop Designer and BroadcastPlan Pro are both made by Equal Access Audio, which designs, installs and commissions hearing loops and Auracast systems.

Common questions

Will Auracast replace hearing loops?

Not soon. HLAA expects loops, FM and infrared to stay in use for some time, alongside Auracast or on their own, and many hearing aids and implant processors worn today have a telecoil but no Auracast. Where a loop works, adding Auracast from the same feed is a practical next step.

Which system suits a confidential meeting room?

Infrared is contained by walls, as long as the windows are covered. A loop can work with a layout chosen to limit the field outside the room, measured from next door at handover. A closed Auracast broadcast needs a code to listen, but the signal itself passes through walls.

Do telecoil users need a receiver with FM, infrared or Auracast?

With FM and infrared, yes: a receiver with a neckloop. With Auracast, listeners whose hearing aids or processors support it join directly; others need a receiver with a neckloop. In a looped room they need nothing extra.