VALIDATION DATA

Every tone behind Measured Accuracy: forecast level versus the level delivered at the eardrum, for every device we have measured. Compare earbuds with over-ear headphones, the two measurement campaigns, left and right ears, and each device on its own.

Tones measured915
Devices 2026 / 20243 / 3
On target100%
Mean offset−0.20 dB
Spread (sd)±0.9 dB

On target = within ±3 dB to 5 kHz and ±5 dB above, the accuracy range ANSI S3.6 specifies for audiometers. Both ears of every device are measured.

Delivered vs forecast

Error by frequency, dB at the eardrum

2026 mean2024 mean±1 sdtarget range
±3 dB±5 dB-6-4-20+2+4+6125 Hz250 Hz500 Hz1 kHz2 kHz4 kHz8 kHz16 kHz

Across 915 tones on our top 3 reference devices, 500 Hz to 8 kHz, 100% were delivered on target, within the accuracy range the ANSI S3.6 standard specifies for audiometers (±3 dB to 5 kHz, ±5 dB above), with a mean offset of −0.2 dB.

Devices
Type
Band
Run
View
How far each tone landed from its forecast
Count of tones per 0.5 dB · purple = inside ±3 dB · values beyond ±10 dB collected in the end bars
-10 dB-5 dB-3 dB0 dB+3 dB+5 dB+10 dB

FullScale is not an audiometer and makes no medical claim. The ANSI S3.6 tolerance is used only as a reference for accuracy.

Top 3 reference devices, 2026: Technics EAH-AZ80, Apple AirPods Pro (2nd gen), KEF Mu3. 2024: Technics EAH-AZ60, Apple AirPods Pro (2nd gen), KEF Mu3. Other devices are shown without names.

One placement per device, no adjustment, measured on a GRAS ear simulator with an Audio Precision APx500. Tones at the microphone noise floor and frequencies a device cannot reach are not counted. Measured in October 2024 and on 27 October 2026.