About fixmic
fixmic is a free microphone test that does one thing well: tell you what is wrong with your mic in plain English.
Why this exists
Every other mic-test site shows you a moving bar and calls it done. That tells you the mic is connected — it does not tell you whether your audio will sound good on a call. fixmic measures four real problems (clipping, background noise, weak signal, electrical hum) and explains exactly which one is hurting you.
How it works
When you click 'Start test', your browser asks for permission to use the microphone. The audio data is processed entirely in your browser using the Web Audio API — nothing is uploaded to any server, ever. When you close the tab or click 'Stop', the microphone access is released.
What we measure
Six raw measurements: peak level, RMS average, noise floor, dynamic range, dominant noise frequency, and hum prominence. Nine diagnostic findings translate those numbers into plain language — for example, 'your signal is too loud and clipping' or 'there is an electrical hum near 100 Hz; try a different USB port'.
How we set the thresholds
Every verdict comes from a fixed number rather than a guess. The grade is based on the ratio between your voice and your room — the dynamic range — and not on absolute loudness, because the absolute level depends entirely on your gain setting. Clipping is only reported once 5% of your speech frames hit the digital maximum, so a single loud word cannot trigger a false alarm. Electrical hum is judged by how sharply a peak stands out from the broadband noise around it, not by how loud it is. The full list of readings, healthy ranges and thresholds is published on the home page under 'What the numbers mean'.
How the guides are kept accurate
Every technical claim in the troubleshooting guides is checked against the vendor's own documentation — Microsoft, Apple, Zoom, Google, Discord — and each guide carries the date it was last reviewed. Menu paths move with every OS release, so a guide that is correct today can be wrong in six months. When a step no longer matches the current interface, we correct the page instead of leaving it standing.
Why it's free
Hosting, the domain, and development time aren't free. The plan is to support the site through Google AdSense — the same advertising network that pays for most independent websites — which is what makes the tool free for users and signup-free. Advertising is not yet running; when it goes live, the test itself will keep running entirely in your browser (the Web Audio API does not expose anything to ad scripts), and we will never sell, share, or have access to your audio.
Who built it
An independent developer who got tired of mic-test sites that did not actually help. The architecture is deliberately simple: React + Vite + static site generation, hosted on Cloudflare Pages.
Try the diagnostic
The fastest way to understand what fixmic does is to run it on your own mic.
Run the microphone test