Spectrum analyzer. See the frequencies in a song or your microphone, live, in your browser.

Questions

What is a spectrum analyzer used for?

Seeing what's in a sound: finding a hum at 50 or 60 Hz, a resonance to cut with EQ, how much low end a mix has compared with a reference, or the pitch of a whistle or tone.

What's the difference between a spectrum and a spectrogram?

A spectrum is one moment: level against frequency. A spectrogram adds time, showing the spectrum as a scrolling picture where brighter means louder, so changes over time are easy to see.

How accurate is the peak frequency?

The analysis uses an 8192-point FFT (about 5.9 Hz per bin at 48 kHz) with interpolation between bins, so a steady tone reads within a hertz or two. The levels are relative to digital full scale, not calibrated sound pressure.

Why does the microphone show less bass or treble than I hear?

Phone and laptop microphones roll off the lowest and highest frequencies, and the browser may apply its own processing on some devices. For a true reading of a song, drop the file in instead.

Is it free and private?

Free, with no sign-up. The microphone and files are analysed inside your browser tab and never leave your device.