Controlled digital signals
Output tools use the Web Audio API to create known oscillators, sweeps, channel panning and polarity relationships. Each source receives a short fade-in and fade-out to reduce clicks. The app-level master gain starts at −18 dB and is capped below full digital level.
The browser still passes audio through its own mixer, operating-system processing, driver, digital-to-analog path, amplifier and physical transducer. The site cannot control or calibrate those stages.
User-confirmed observations
A digital left-channel signal proves what the page requested, not which physical speaker produced it. The user therefore confirms side, audibility, balance and distortion. An unanswered question is omitted rather than treated as a pass.
Ranked diagnostic rules
The diagnosis engine maps explicit symptoms and confirmations to a small set of plausible causes. Results use “likely,” “possible,” or “check” language and show the evidence behind the ranking. They are troubleshooting hypotheses, not automatic hardware determinations.
Browser and measurement limits
| Signal | Browser knows | Browser does not know |
|---|---|---|
| Output tone | Frequency, waveform, digital channel and app gain | Physical loudness, driver health, room response or perceived side |
| Microphone | Relative samples, dBFS and browser sample rate | Calibrated sound pressure or flat microphone response |
| Spectrum | Relative FFT-bin energy | Laboratory frequency response or source identity |
Audio safety
Every test requires a user gesture and begins at reduced app gain. Tone generation is bounded to 20 Hz–20 kHz and the site warns against hearing-threshold tests. System and hardware volume remain outside the browser’s control, so users must begin low and stop if sound is uncomfortable.
Local processing and retention
Output signals stay on the device. Microphone samples are analyzed locally. Optional microphone recordings last no more than ten seconds and remain only in current page memory. Compact diagnostic sessions contain answer and cause codes, are stored locally for up to ninety days, and can be cleared at any time.
For analytics details, see the privacy policy.
Last reviewed: August 3, 2026.