Audio spectrogram viewer

What it does

Visualise a short audio recording as frequency energy over time and export a labelled image.

How to use it

1. Choose an audio file up to 10 MB, 30 seconds and eight channels, in a browser-supported format.
2. Select FFT size, generate the spectrogram and download PNG or frequency-data JSON.
3. Processing stays in this browser. No sign-up or upload.

Example

A steady 1,000 Hz tone appears near 1 kHz throughout the recording.

Methodology

Channels are averaged to mono. A Hann-window FFT reports one-sided amplitudes on linear frequency axes with a −100 dBFS floor.

Limitations

FFT sizes 256–2,048, up to 600 frames. Browser decoding can resample audio; opposite-phase channels may cancel. Not calibrated sound pressure or a diagnostic tool.

Automation

This tool runs in your browser. No upload API or MCP endpoint is available.