INDEPENDENT TESTING
Microsuction noise, measured at the eardrum
Independent testing of Zephyr against a Zoellner sucker by the University of Salford. This page is where every noise claim Spoke Medical makes is verified: the method, every figure we quote, the report's own limitations, and how to obtain the report.
Key findings
- The University of Salford measured microsuction noise at the eardrum of an anatomical ear model, 30 simulated wet-wax removals per device, same suction pump, in report 07479 issued 8 October 2026.
- A Zoellner sucker averaged 118.3 dB(A) over the procedure. Zephyr averaged 93.4 dB(A): 24.9 dB quieter, about 5 times quieter in perceived loudness.
- On entry to the ear, the Zoellner averaged 108.5 dB(A) and Zephyr 64.4 dB(A) with its airflow control button fully depressed: 44.1 dB quieter, about 21 times quieter in perceived loudness.
- The Zoellner exceeded the UK Noise at Work exposure limit value for daily exposure in 17 of 30 runs and for peak level in 29 of 30. Zephyr exceeded them in 1 and 5 runs.
- The results are from a simulated scenario and cover acoustic effects only, in the report's own words.
Page maintained by Spoke Medical. Clinical review: Patrick Axon, Consultant Otologist, and Neil Donnelly, Consultant ENT Surgeon. Last reviewed 12 October 2026.
Determination of the noise emission levels at a simulated eardrum due to noise from earwax suction devices operated in a simulated ear-canal
Request a copy of the report →THE CLAIMS, AND WHERE THEY COME FROM
5× quieter microsuction. 21× quieter as it enters the ear.
Both figures are perceived-loudness conversions of decibel differences measured by the University of Salford at the eardrum of an anatomical ear model. The report states the rule of thumb used: a 10 dB change in level is perceived as twice as loud.
How each advertised figure is derived
| Claim | Zephyr | Zoellner 30° suction tube | Difference | Perceived loudness (10 dB = 2×) |
|---|---|---|---|---|
| “5× quieter microsuction” — full procedure, average LAeq | 93.4 dB(A) | 118.3 dB(A) | 24.9 dB | 22.49 ≈ 5.6×, published as 5× |
| “21× quieter as it enters the ear” — Phase 1, average LAeq, Zephyr’s airflow control button fully depressed | 64.4 dB(A) | 108.5 dB(A) | 44.1 dB | 24.41 ≈ 21.3×, published as 21× |
The same decibel differences can be expressed on other scales. As sound-pressure ratios (10dB/20) they are 17.6× and 160×; as sound-energy ratios (10dB/10) they are about 310× and 25,700×. Where this site says “16× lower sound pressure”, that is the 24.9 dB difference on the sound-pressure scale, rounded down. Advertising uses the perceived-loudness scale because it answers the question a patient asks: how much quieter does it sound.
Four of the 30 Zephyr entries were below what the microphone could detect, so the report treats Zephyr’s Phase 1 average as an upper limit. The true difference on entry is at least 44.1 dB.
RESULTS
Every figure the report gives, at the simulated eardrum
Arithmetic averages of 30 simulated wet-wax removals per device, with the standard deviation the report gives for each. A-weighted unless marked dB(C). Table 4 of the report.
| Measurement | Zephyr (SD) | Zoellner (SD) | Difference |
|---|---|---|---|
| Phase 1 · entry to the ear · average LAeq | 64.4 dB(A) (14.7) | 108.5 dB(A) (4.8) | 44.1 dB |
| Phase 3 · wax clearing · average LAeq | 95.2 dB(A) (21.6) | 119.0 dB(A) (18.1) | 23.8 dB |
| Full procedure · average LAeq | 93.4 dB(A) (18.1) | 118.3 dB(A) (8.2) | 24.9 dB |
| Full procedure · loudest 1/32-second level (Max-LAeq) | 114.1 dB(A) (16.4) | 136.9 dB(A) (7.4) | 22.8 dB |
| Full procedure · sound exposure level (LAE) | 105.8 dB(A) (18.2) | 132.0 dB(A) (8.2) | 26.2 dB |
| Full procedure · peak (LCpeak) | 129.7 dB(C) (13.6) | 150.6 dB(C) (5.5) | 20.9 dB |
| Daily personal noise exposure (LEP,d, 8-hour normalised) | 61.2 dB(A) (18.2) | 87.4 dB(A) (8.2) | 26.2 dB |
Mean procedure duration: Zephyr 17.5 s, Zoellner 23.3 s. The report gives no inferential statistics; the figures above are averages and standard deviations as published. Phase 2 (sucker in contact with the wax, airflow blocked) is not reported separately: the laboratory found those levels at the microphone’s self-noise floor of around 40 dB with random spikes and judged that presenting them as a comparison “is likely to be misleading”. Phase 2 is included in the full-procedure averages.
Against the UK Control of Noise at Work Regulations 2005
The report compares each run with the limit values in the regulations. They govern employees rather than patients; the report uses them as the recognised benchmark for the hearing risk the measured levels represent. The Exposure Limit Value is the level the regulations say must never be exceeded.
| Daily exposure, LEP,d | Limit | Zephyr runs over | Zoellner runs over |
|---|---|---|---|
| Lower exposure action value | 80 dB(A) | 2 of 30 (6.7%) | 24 of 30 (80.0%) |
| Upper exposure action value | 85 dB(A) | 1 of 30 (3.3%) | 21 of 30 (70.0%) |
| Exposure limit value (must never be exceeded) | 87 dB(A) | 1 of 30 (3.3%) | 17 of 30 (56.7%) |
| Peak, LCpeak | Limit | Zephyr runs over | Zoellner runs over |
|---|---|---|---|
| Lower exposure action value | 135 dB(C) | 14 of 30 (46.7%) | 30 of 30 (100%) |
| Upper exposure action value | 137 dB(C) | 10 of 30 (33.3%) | 30 of 30 (100%) |
| Exposure limit value (must never be exceeded) | 140 dB(C) | 5 of 30 (16.7%) | 29 of 30 (96.7%) |
Zephyr did exceed the exposure limit value in some runs, “by a much lower amount, and in a much smaller number of procedures” (report §11.3). Highest values recorded: Zephyr 89.1 dB(A) LEP,d; Zoellner 98.4 dB(A) LEP,d and 159.3 dB(C) LCpeak.
METHOD
How the measurements were made
No noise test code exists for devices used inside the ear canal, so the laboratory developed its method with reference to ISO 3744:2010. The laboratory is UKAS-accredited to ISO 17025 for standard tests; this bespoke test falls outside the scope of that accreditation and was run under the same quality system.
Test environment
Hemi-anechoic chamber at the University of Salford. The ear model was mounted on a tripod with the ear canal 1.25 m above the floor.
Ear model
A 3D-printed, true-to-life pinna and ear canal based on CT anatomy, printed in soft polymer resins by Cosa Ltd. Canal diameter about 5.8 mm (about 5 mm with skin); 30 mm from tragus to a closed tympanic membrane. A medical speculum was mounted at the canal entrance, as in a real procedure.
Microphone at the eardrum
Brüel & Kjær Type 4182 probe microphone, 50 mm probe tube, inserted through a sealed hole so its tip was flush with the inner surface of the simulated eardrum. Calibrated before the session with a B&K 4230 and inspected after every batch of ten runs. Recorded on a B&K PULSE analyser.
Wax simulant
Identical 3 × 3 × 6 mm aliquots of synthetic “wet wax”, 3D-printed in gel-matrix material to a moist, firm consistency, placed about 1 mm from the eardrum. One wax consistency was tested.
Suction source
The same Vacate 7325 portable medical suction unit for both devices, outside the chamber, at its maximum setting of 500+ mmHg. Zephyr and the Zoellner were the only variable.
Devices and operator
30 single-use Zephyr units with the standard tip, and 30 Zoellner 30° suction tubes with 6-gauge tips, tested in batches of ten. Every removal was performed by a fully qualified surgeon practised in earwax removal, using medical loupes, with Zephyr’s airflow control button fully depressed on entry.
What was recorded
1/32-second A-weighted levels and one-twelfth-octave spectra from 77 Hz to 21.75 kHz for the whole of each run, plus the C-weighted peak. Phase 1 (entry), Phase 2 (in contact with wax) and Phase 3 (wax clearing) were identified from each run’s time history.
Averages reported
Each parameter is the arithmetic mean of the 30 runs, with its standard deviation. The LAeq figures are averages of the 1/32-second values over each phase and over the full procedure. Daily exposure (LEP,d) is normalised to an 8-hour shift from each run’s level and duration.
LIMITATIONS, IN THE REPORT’S WORDS
What these measurements can and cannot tell you
“The measurements presented here are obtained from a simulated scenario and may not be the actual values obtained in a real scenario with a real patient, therefore they should be considered to be an indication of the potential acoustic levels at the eardrum.”
“The results are also limited to measurements of the acoustic levels observed during the experiment, and implications can only be drawn on potential acoustic effects. No assessment can be made, or conclusions drawn, from these results on any other effects on patient hearing that are related to non-acoustic effects (for example the effect of the air flow itself).”
“The Zephyr unit produces a significantly lower exposure in this simulated scenario, although it does also exceed the Exposure Limit Value in some instances (by a much lower amount, and in a much smaller number of procedures).”
“The standard deviation of the Zephyr measurements is higher than the standard deviation of the Zoellner measurements … This is likely to be due to the fact that the noise created by the Zephyr unit is affected by the manual operation of the unit by depressing the button to activate or control the airflow.”
Spoke Medical adds: one wax consistency was tested; the comparator was one model of Zoellner sucker; and the report contains no statistical tests, so any claim of statistical significance you see elsewhere is a calculation from the report’s per-run data, not a finding of the laboratory.
WHAT THE DATA SHOWS
Three things the measurements make clear
Entry is where the difference is largest
With a conventional sucker, airflow is already running as the tip travels through the speculum, and the eardrum sees a steady 108.5 dB(A), about the level of a live concert on the report’s reference scale. With Zephyr’s airflow control button fully depressed, the average was 64.4 dB(A), about ordinary conversation, and four of the 30 entries were below what the microphone could detect.
Clearing the wax dominates the exposure
For both devices the loudest part of the procedure is Phase 3, when the wax begins to clear and air flows again. That is why the whole-procedure difference, 24.9 dB, is smaller than the difference on entry: the report notes that exposure “is dominated by phase 3”. Zephyr is still 23.8 dB quieter there.
Operator control is the mechanism
The report describes the Zoellner as offering “no control for the operator”, and attributes Zephyr’s wider spread of results to the clinician’s use of the button. The airflow “can be incrementally reduced by the operator by depressing the button … so that the smallest airflow necessary is used”.
QUESTIONS
Microsuction noise: the questions people ask
How loud is microsuction at the eardrum?
In University of Salford testing on an anatomical ear model, a conventional Zoellner sucker averaged 118.3 dB(A) at the simulated eardrum over a wet-wax removal, with a peak of 150.6 dB(C). On the report's reference scale 110 dB is a live concert and 130 dB an aeroplane taking off 100 m away.
Is Zephyr quieter than a Zoellner sucker?
Yes. Over the full simulated procedure Zephyr averaged 93.4 dB(A) against 118.3 dB(A) for the Zoellner, 24.9 dB lower, and on entry to the ear 64.4 dB(A) against 108.5 dB(A), 44.1 dB lower, measured at the eardrum of an anatomical ear model with the same suction pump.
What does "5× quieter" or "21× quieter" mean?
They are perceived-loudness conversions of the measured decibel differences, using the rule stated in the Salford report that a 10 dB change is perceived as twice as loud: 24.9 dB is about 5.6 times, published as 5×, and 44.1 dB about 21.3 times, published as 21×. As sound-pressure ratios the same differences are 17.6× and 160×.
Who carried out the testing, and was it independent?
The National Institute of Airborne Acoustic Metrology at the University of Salford carried out the measurements and wrote report 07479, issued on 8 October 2026. Spoke Medical commissioned and paid for the work; the laboratory designed the method, took the measurements and authored the report.
Does the testing show that microsuction damages hearing, or that Zephyr is safe?
Neither. The report measures sound levels in a simulated ear and states that its results are an indication of potential levels at the eardrum and that conclusions can be drawn on acoustic effects only. It compares the levels with the UK Noise at Work limit values: the Zoellner exceeded the exposure limit value in 17 of 30 runs and Zephyr in 1 of 30.
How can I check these figures?
Every figure on this page comes from Tables 4, 5 and 6 and section 11 of University of Salford report 07479. Request a copy from info@spokemedical.com; qualified reviewers can also ask for the 30 per-run results for each device.
TERMS USED ON THIS PAGE
Reading the acoustic figures
- dB(A) and dB(C)
- Decibels weighted for human hearing. A-weighting follows the ear’s sensitivity at ordinary levels and is used for average and exposure figures; C-weighting is flatter and is used for peaks.
- LAeq
- The A-weighted equivalent continuous level: the steady level that would carry the same sound energy as the varying sound over the same time. In this report it is the average of 1/32-second readings over a phase or the whole procedure.
- Max-LAeq, 1/32 s
- The loudest single 1/32-second reading in a run. Called LAmax in some earlier descriptions of this data.
- LAE (sound exposure level)
- The total sound energy of an event expressed as if it had lasted one second, so events of different lengths can be compared.
- LCpeak
- The highest instantaneous C-weighted sound pressure in a run, with no time averaging. The regulations set peak limits because impulsive sound can damage hearing on its own.
- LEP,d (daily personal noise exposure)
- A worker’s noise dose normalised to an 8-hour shift, defined in the Control of Noise at Work Regulations 2005. The report calculates it from each run’s level and duration as a benchmark; the regulations govern employees, not patients.
- Exposure limit value
- The level the Noise at Work Regulations say must never be exceeded: 87 dB(A) daily exposure and 140 dB(C) peak. The lower and upper exposure action values (80 and 85 dB(A); 135 and 137 dB(C)) trigger employer duties short of that.
- Hemi-anechoic chamber
- A room whose walls and ceiling absorb almost all sound, over a reflecting floor, so that what the microphone records comes from the source rather than the room.
- Perceived loudness
- How much louder a sound seems to a listener. The report applies the common rule that a 10 dB increase is perceived as a doubling of loudness; the 5× and 21× figures use it.
CONTEXT
Why this research matters
Microsuction is the gold standard for cerumen removal, but noise generated during the procedure has been associated with serious adverse outcomes. See microsuction noise levels and noise-induced hearing loss for clinicians in the learn centre.
Documented Risks of Microsuction Noise
- Noise-induced hearing loss
- Tinnitus (new onset or exacerbation)
- Vertigo
- Patient discomfort and anxiety
Regulatory Context
- ENT UK 2024 guidance identifies noise as a clinical risk during microsuction
- Control of Noise at Work Regulations 2005: hearing protection must be worn above the 85 dB(A) upper exposure action value; 87 dB(A) must never be exceeded
- The conventional sucker averaged 118.3 dB(A) at the simulated eardrum over the full procedure
Sources
- Lomax C, Stocks R, Spencer A. Determination of the noise emission levels at a simulated eardrum due to noise from earwax suction devices operated in a simulated ear-canal. Report 07479. National Institute of Airborne Acoustic Metrology, University of Salford; issued 8 October 2026. Available on request from Spoke Medical.
- The Control of Noise at Work Regulations 2005, SI 2005/1643.
- ISO 3744:2010, Acoustics: Determination of sound power levels and sound energy levels of noise sources using sound pressure. Engineering methods for an essentially free field over a reflecting plane. The reference standard for the report’s method.
- RNID, How loud is too loud? The everyday-sound scale the report uses for context.
- World Health Organization (1999), Guidelines for community noise. Source of the 140 dB peak and 110 dB(A) limits the report cites for acute hearing damage.
- Lutman M, Davis A, Ferguson M (2008). Epidemiological evidence for the effectiveness of the noise at work regulations. HSE Research Report RR669.
- Brookhouser PE, Worthington DW, Kelly WJ (1992). Noise-induced hearing loss in children. The Laryngoscope 102(6): 645–655. doi:10.1288/00005537-199206000-00010
- Voss SE, Horton NJ, Fairbank KE, Xia L, Tinglin LRK, Girardin KD (2020). Measurements of ear-canal cross-sectional areas from live human ears. J Acoust Soc Am 148(5): 3042. Source of the ear-canal dimensions used for the model.
How to verify these claims
- Every figure on this page is taken from Table 4, Table 5, Table 6 and section 11 of report 07479, which also contains the 30 per-run results for each device.
- Request the report by email: info@spokemedical.com. Qualified reviewers may ask us for the per-run data in spreadsheet form.
- Perceived-loudness multipliers use the rule stated in the report (section 10.1): a 10 dB change is perceived as twice as loud, so a difference of d dB corresponds to 2d/10.
- To cite the report: Lomax C, Stocks R, Spencer A. Determination of the noise emission levels at a simulated eardrum due to noise from earwax suction devices operated in a simulated ear-canal. University of Salford, report 07479, 8 October 2026. To cite this page: Spoke Medical, “Microsuction noise, measured at the eardrum”, spokemedical.com/research/, reviewed 12 October 2026.
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