Is my audio uploaded anywhere?

No. The file is decoded and the spectrogram is drawn by your browser. Nothing is sent to a server and nothing is stored.

How do I read a spectrogram?

Time runs left to right, frequency bottom to top, and brightness is level. Horizontal lines are sustained pitches, vertical lines are transients such as drum hits, and a bright band across the bottom is bass energy.

How can I see whether a file came from an MP3?

Look for a hard horizontal edge near the top with nothing above it, usually somewhere between 15 and 20 kHz. Lossy encoders throw that region away, and converting the file back to WAV does not bring it back. It is strong evidence, not proof.

Which FFT size should I use?

A larger window resolves pitch more precisely and blurs timing; a smaller one does the opposite. 2048 is a sensible default at 44.1 kHz. Use 8192 to inspect a bass note or a resonance, and 1024 to see exactly where a transient sits.

Why does the logarithmic scale look so different?

Because hearing is logarithmic. On a linear scale half the picture covers 10 to 20 kHz, where very little musical information lives. The logarithmic scale gives each octave the same space, which is closer to what you perceive.

Free tool

Spectrogram Generator

See the whole frequency content of a file over time: sustained pitches, transients, resonances and the ceiling a lossy codec left behind.

Your file is decoded and drawn in this browser tab. Nothing is uploaded, nothing is stored.

Your file

Decoded and drawn in this tab. Nothing is uploaded or stored.

Choose an audio file

WAV, MP3, FLAC, AIFF, M4A, OGG — up to 250 MB.

Detail

How this works

A spectrogram is a short-time Fourier transform drawn as an image: the audio is cut into overlapping windows, each window is converted from samples into frequencies, and the result becomes one vertical stripe of the picture. Everything you see is arithmetic over your samples, so the same file always draws the same image.

The window size is the one real trade-off. Time and frequency resolution are inversely related, so a long window tells you the pitch precisely and smears the moment it happened, while a short window pins the moment and blurs the pitch. That is a property of the transform, not a limitation of this tool.

What producers use it for: finding a resonance that only shows up on one note, checking whether a stem was sourced from a compressed file, spotting a hum or a click that hides under the mix, and seeing how much of a busy arrangement is stacked in the same octave.

FAQ

Frequently asked questions

Toolbox

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Train your sound. Generate your song.

ANYANO is the bigger version of this: prepare music you own, train a Sound that stays private to your account, then generate from it.