Audio / Measure
Online Audio Spectrum Analyzer and Spectrogram (Microphone)
Watch the frequencies in sound from your microphone in real time: a live spectrum on a logarithmic axis from 20 Hz to 20 kHz, a scrolling waterfall spectrogram, and the loudest frequency with its nearest musical note.
Online Audio Spectrum Analyzer and Spectrogram (Microphone): The microphone signal is analysed with a fast Fourier transform of 8,192 samples, splitting it into bins about 6 Hz wide at 48 kHz. The level of each frequency is drawn on a logarithmic scale, the strongest peak is refined between bins and named as a note, and each new spectrum scrolls into the waterfall below, brighter for louder. Runs 100% locally in your browser with zero server file uploads.
- Category
- Everyday tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
The analyser takes the microphone signal through a fast Fourier transform of 8,192 samples, giving bins about 6 Hz wide at 48 kHz, and draws the level of each frequency on a logarithmic axis from 20 Hz to 20 kHz. The waterfall below scrolls the spectrum over time, brighter for louder. Phone and laptop microphones roll off at the low and high ends, and the level is relative, not calibrated dB SPL. Nothing is recorded or sent.
Reading the spectrum
A sung or played note shows a peak at its fundamental and smaller peaks at whole-number multiples, the harmonics that give each instrument its sound. Mains hum shows at 50 or 60 Hz and its multiples, depending on the country.
Testing with a tone
Play a known frequency from the tone generator on another device: the peak should appear at that frequency, which also shows how your microphone responds across the range.
How to use it
- Press start and allow the microphone.
- Make the sound you want to analyse.
- Read the spectrum, the waterfall, and the loudest frequency.
Privacy & limitations
The microphone is analysed in your browser; nothing is recorded or sent.
Related tools
Frequently asked questions
What can I use it for?
Finding feedback and room resonance frequencies, checking an instrument's pitch and overtones, spotting electrical hum at 50 or 60 Hz, and seeing how speech or birdsong looks.
Are the levels in dB SPL?
No: they are relative to the microphone's full scale, and phone and laptop microphones are not calibrated. Use the sound level meter for an estimate of loudness.
Why is there little below 100 Hz?
Small built-in microphones are insensitive at low frequencies, and browsers may filter them.
Free tool · runs in your browser · no account required