FFT spectrum analyzer Β· A-weighted dB Β· noise floor Β· record & playback Β· frequency sweep. No upload, no app.
This uses the Web Audio API with a 4096-point FFT analyser at 48kHz sample rate. The dB meter applies A-weighting β the same standard used in professional audio measurement β which weights frequencies according to how the human ear perceives loudness. The spectrum display shows frequency bins from 20Hz to 20kHz in real time.
The noise floor is measured by tracking the minimum sustained level over 3 seconds of silence. A good quiet room is below β50 dB. The dominant frequency shows the strongest bin in the FFT at any given moment.
This tool tests your microphone and speakers directly in your browser using the Web Audio API. For the microphone, it shows a real-time FFT (Fast Fourier Transform) spectrum analyzer and an A-weighted decibel (dBa) meter. For speakers, it generates precise test tones at specific frequencies so you can verify your audio output quality.
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 β 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 β 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 β 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.