Most loops that buzz, fade or fall silent can be fixed. We measure, find the cause and fix what’s broken, usually without starting over.
Short answer
Most hearing loops that go silent, buzz or turn weak in some seats can be repaired. The cause is almost always findable with a field-strength meter and a methodical search: a cut wire, a lost audio feed, metal the design didn’t allow for, or a failed driver. Replacing the system is rarely the first answer, and never the right one before the cause is known.
This page is for whoever gets the complaint: the facilities manager, the sound volunteer, the library or city hall staff member, the integrator with a job that won’t pass. The same faults turn up in churches, council chambers, courts and libraries, senior living chapels and TV lounges and theaters, and we work on systems from any installer.
Each symptom points to a short list of causes, and each cause leaves a trace a meter can find. Treat the table as a starting point, not a verdict: two different faults can sound the same to a listener, which is why we measure before anyone replaces anything.
| Likely causes | What we measure | |
|---|---|---|
| Silent everywhere | A cut or broken wire, often from flooring work; a failed driver; no audio reaching the driver (a muted or re-patched mixer output). | Loop resistance and leakage to ground; the signal at the driver input; the driver’s output current. |
| Buzz or hum | Magnetic noise from lighting, dimmers, transformers or wiring, which telecoils pick up directly; or hum in the audio feed, sometimes a ground loop. | Background noise with the loop off, then on. Hum that stays with the loop off is the building, not the loop. |
| Weak in some seats | A perimeter loop too wide for the room; steel or rebar under those seats; a dead section of a phased array; a seam where two areas cancel. | Field strength across the seating at the listening height (about 4 ft seated), against the ±3 dB window. |
| Muffled, consonants lost | Metal absorbing the high frequencies, with no correction set; a driver running out of voltage on a long loop; heavy compression in the feed. | Frequency response at 100 Hz, 1 kHz and 5 kHz against the 1 kHz level; driver headroom on speech peaks. |
| Works some days, not others | Tape fatigued by a flexing wood floor; a slab crack that is still moving; a poor splice or loose connection. | The loop circuit section by section while the route is walked; every joint we can reach. |
| Stopped after new flooring or a renovation | Tape cut and covered over by the flooring crew; new metal such as a steel ceiling grid; electrical work that added noise or moved the feed. | Continuity and leakage to ground, section by section; a fresh field map against the original report, if one exists. |
| Fault light on the driver | On many drivers, the loop is open, shorted or outside the load the driver expects. In a phased array, one of two drivers may have failed. | Loop resistance against the driver’s rated load, each channel on its own. |
| Heard next door or on stage | No spill control in the design; cancellation loops sized by rule of thumb, or too close to a stage, where they can make things worse. | Spill in the next room or on stage. IEC 60118-4 sets no spill limit, so we measure against the project’s target. |
| Meter says fine, users can’t hear | The feed: the wrong mix, missing microphones, or compression that flattens speech. Or the hearing aid: no telecoil, or its program not turned on. | What is actually in the feed, by listening on a receiver; field strength at the seats people complain about. |
| Auracast drops out or hearing aids can’t join | A 48 kHz-only broadcast hearing aids can’t use; bodies absorbing the signal in a full room; a muted source; busy Wi-Fi in a large venue. | The transmitter’s on-air settings and packet loss; a walk test; join tests with a phone, a hearing aid and a receiver. |
IEC 60118-4 references field strength to 400 mA/m at 1 kHz (0 dB). A system designed and verified to it holds the listening area within ±3 dB of that level, keeps the response from 100 Hz to 5 kHz within ±3 dB of the 1 kHz level, and has low background magnetic noise: IEC 60118-4 recommends background magnetic noise of about −47 dB(A) re 400 mA/m or quieter, and treats up to −32 dB(A) as acceptable in some rooms. The outer 2 ft of the loop area is left out of the flatness figures.
A driver’s metal-loss correction can restore treble lost to steel; it can’t fill the spatial dip in the middle of a wide perimeter loop. Two linked drivers usually mean a phased array, not a figure-8, so each channel is checked on its own, and overlapping arrays need drivers from the same series. We never generate the test signal and measure it on the same device.
Five safe checks often find the problem or narrow it down. None involves opening equipment, lifting flooring or touching electrical wiring. Write down what you find and take photos; that alone can save an hour on site.
Stop here and call
Don’t open the driver, change its level or tone controls, lift flooring, or cut and splice the wire. The settings were set by measurement, and changing them by ear usually makes some seats worse (see why turning it up isn’t a fix). Send us your notes and photos of the driver, the mixer outputs and the room, plus any drawings or old test report.
Every repair visit follows the same five steps. The measuring comes before any opinion about what to replace, and the last step gives you before-and-after numbers in writing.
What do people hear, where, and since when? Your notes, photos, drawings and any old report, plus what changed.
Field strength across the seating, frequency response, background noise with the system off, the feed, and the loop circuit.
What’s installed against what was designed: route, splices, phase, metal, driver settings, audio chain.
Reconnect, re-route, reset or swap a part, then measure again. Bigger changes get modeled first.
What we corrected, what’s left, what each fix costs, with before-and-after readings.
In plain English: first find out whether the loop makes any sound, then whether it’s even, then what’s wrong with the sound. Each answer points to a different fix.
Anyone with a receiver can ask the same three questions. No sound and no input at the driver means the feed; input but silence means the wire or the driver. Sound that varies from seat to seat is a coverage problem. Even but bad sound is noise, lost treble or an intermittent joint, and each has its own measurement.
Turning up the driver raises every seat by the same amount. It can’t flatten an uneven layout, restore treble lost to metal, remove magnetic noise, correct a phase error or clean up a bad feed. It usually trades one complaint for another: the weak seats improve while others get too loud or heard next door.
In plain English: turning the loop up lifts every seat by the same amount, so the weak middle improves while the side seats get too strong. The shape of the line never changes.
Extra current has one legitimate use: bringing a system that was set too low back to the reference level, with a meter, not by ear. Past that it adds clipping, heat and spill. Here, even the ideal setting leaves about a fifth of the room outside the window; the fix is a different layout.
Repair when the system could meet IEC 60118-4 when it was new and something has since broken or changed. Redesign the part that’s wrong when the layout could never have covered that room. Even then it’s rarely all or nothing: drivers, feed cables and the rack connection can often stay.
Usually a repair
Usually needs redesign
How we decide: we model your room in Hearing Loop Designer, the design software we build, to see whether the existing layout could ever have met the standard there. If it could, we chase the fault. If not, we show you the model prediction beside our measurements and price the smallest change that fixes it. If that’s a new layout, here’s how we design and install a loop.
When a loop works for years and then fails, the cause is usually physical and often preventable. These lessons come from David Harmon’s more than 15 years of installing and repairing loops.
It’s a common myth that concrete corrodes loop tape. Dry concrete never does. The trouble is moisture trapped under vinyl-backed flooring that can’t dry out. Water wicks into tiny cracks in the tape’s thin insulation, current leaks to ground, and the tape can eat itself to an open circuit.
Field rule of thumb: highest risk is a slab on soil, under vinyl-backed flooring, near an entrance where salted snow is tracked in.
Even experienced carpet installers commonly cut loop tape. Before new flooring goes down, we brief the general contractor and the flooring crew and leave a loud cut-wire alarm on the circuit, with a fresh battery and a phone number on it, so a cut gets reported instead of covered.
A cut reported while the floor is open is a short solder repair. A hidden one means tracing it and lifting finished flooring.
On wood floors, boards that flex against their neighbors fatigue the tape until it cracks, and the fault comes and goes with foot traffic. On concrete, a crack that’s still moving can snap tape years later, so at a live crack we fold the tape back on itself to leave slack.
Even small flexes between neighboring boards are enough to fatigue copper tape.
Every repair under a floor ends the way a new install does: we prove each circuit works with a test driver before anything is covered, because a sealed-in mistake is the expensive kind.
We work on loops and Auracast systems from all major brands, whoever installed them. If yours is still under the original installer’s warranty, call them first; we’ll tell you if we think that’s the right move. We’re glad to work alongside the original installer, and we report what we measure without running anyone down.
Most Auracast problems we see are settings and placement, not broken hardware. Small rooms with one transmitter rarely give trouble; the problems show up in larger venues.
How we design and walk-test Auracast systems
Photos and a short conversation come first, at no charge. Most repairs then start with a diagnostic visit, the same visit as our Loop Health Check: $500 within about an hour’s drive of Buffalo Grove, or anywhere on a day we’re already in your area (longer trips are quoted first), credited in full toward the repair if you book it within 90 days. Once we know the cause, we quote the repair in writing.
After a major repair, you may want the system measured and documented again: how we test a loop to IEC 60118-4.
Usually one of two things. Telecoils pick up any magnetic field, so lighting, dimmers, transformers and building wiring can hum in a listener’s ear even with the loop off. Or the hum is in the audio feed, sometimes from a ground loop between the mixer and the driver. The quick test: if the hum is still there with the driver switched off, it’s the building, not the loop.
Most often it’s the layout. A simple perimeter loop sags in the middle, and the wider the room, the deeper the dip: about 7.5 dB at the center of a long loop 66 ft wide, before any metal. Rebar under part of the room, a dead section of a phased array, or a seam where two areas cancel can do it too. A seat-by-seat field map shows which.
Something changed. Tape under vinyl on a slab can corrode from trapped moisture, wood floors flex until tape cracks, and flooring crews cut tape during renovations. Just as often the feed changes: a new console or a re-patched output stops sending audio to the loop. Drivers fail too. Tell us what changed in the building and roughly when the problem started.
Usually. We locate the fault with meters before anything is lifted, so only the flooring near the break comes up. Carpet tile is the easy case: a few tiles. Sheet carpet can often be pulled back from the nearest wall or seam by a carpet installer. Where a long run has corroded under glued flooring, a new route, sometimes in the ceiling below, can cost less than patching.
Yes, including systems a venue set up itself. The usual causes are a muted source, a broadcast format hearing aids can’t use, too little coverage for a full room, and busy Wi-Fi in large venues. We read the transmitter’s actual settings, walk-test the room and run join tests. See how we plan and verify Auracast systems.
We reply within 2 business days. The quickest start is a text with photos of the loop driver’s front panel and the mixer: we can often say what’s wrong from those, and some problems are fixed by phone before anyone travels. If a service, meeting or performance is coming up, say so, and we’ll tell you honestly the earliest date we can be there.
A few lines and photos of the driver and the room are enough to start. You’ll hear back from David within 2 business days. Prefer a scheduled check-up? Book a health check visit.