FFT spectrum analyzer · A-weighted dB · noise floor · record & playback · frequency sweep. No upload, no app.
This tool tests your microphone and speakers directly in your browser using the Web Audio API — nothing is uploaded or installed. For the microphone, it runs a 4096-point FFT analyser at a 48 kHz sample rate, displaying a real-time spectrum from 20 Hz to 20 kHz alongside an A-weighted decibel (dBa) meter that follows the same IEC 61672 standard used in professional audio measurement. For speakers, it generates precise sine-wave test tones at specific frequencies so you can verify your audio output quality.
The noise floor is the minimum sustained level the tool measures over a few seconds of silence — a good quiet room sits below –50 dB, while anything higher points to ambient noise, mic self-noise, or excess gain. The dominant frequency, meanwhile, shows the single strongest bin in the spectrum at any moment, which is handy for spotting hum or interference.
FFT (Fast Fourier Transform) decomposes your microphone input into individual frequency components, displayed as a real-time bar chart. It shows which frequencies (bass, midrange, treble) are present in the incoming audio signal.
A-weighted decibels (dBa) measure sound levels adjusted to match how human ears perceive loudness. The A-weighting reduces the influence of low and very high frequencies that humans are less sensitive to, making it a better measure of perceived loudness than raw dB.
Test tones generate pure sine waves at specific frequencies — typically 100 Hz (deep bass), 1000 Hz (midrange), and 10,000 Hz (high treble). Playing these reveals frequency response issues: if you cannot hear the 10 kHz tone, your speakers may have limited high-frequency response.
All microphones pick up ambient sound. The FFT will show noise floor peaks in the lower frequencies. For cleaner audio in calls and recordings, use a directional (cardioid) microphone and enable noise cancellation in your system settings or video call software.
Click "Start Mic Test" and speak — you should see the waveform move and the dBa meter rise. If nothing moves, check that the correct microphone is selected in the dropdown and that browser permission for microphone access is granted.
Ensure your volume is turned up and the correct audio output device is selected. Some Bluetooth headphones may mute certain frequency ranges. If you cannot hear 10 kHz tones, this is common in adults over 40 — high-frequency hearing loss is normal with age.
This tool gives a good general indication of microphone and speaker performance. For professional audio measurement, dedicated hardware analyzers provide more precise frequency response curves. This tool is best for quick verification and diagnostics.
A-weighting is an international standard (IEC 61672) that filters the dB measurement to match how human hearing perceives different frequencies. Human ears are most sensitive around 2–4 kHz and less sensitive at very low and very high frequencies. A-weighted dB (dBA) is more meaningful than flat dB for measuring perceived loudness.
High noise floor (above –40 dB) usually means: (1) ambient noise in your room (air conditioning, traffic), (2) cheap microphone with high self-noise, (3) gain too high in system settings, or (4) USB interference on the mic cable. For video calls, noise floor below –55 dB is ideal.
No. All audio processing runs in your browser using the Web Audio API. Nothing is transmitted to any server. If you use the Record feature, the file is generated entirely on your device and never leaves your browser.