Measure the visual pace of music.

Upload an audio file to calculate its SCPI score on a 1–180 scale. Files are analysed in temporary memory-backed storage and deleted immediately afterwards.

Public SCPI spectrum

The ten latest opt-in submissions, arranged by SCPI value — not upload time.

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How SCPI works

SCPI measures the visual pace of an audio track from its spectrogram: a time-based image of its frequency content.

From sound to colour

The audio is rendered as a spectrogram and divided into twelve time slices. SCPI evaluates the central ten slices, deliberately ignoring the beginning and end where silence, fades, or encoding artefacts can distort a track’s character.

Warm colour, spectral pace

For each selected slice, SCPI measures the proportion of warm spectral colours — red, pink, dark orange, orange, yellow, light yellow and pale yellow. Their average is mapped to a 1–180 scale: lower values usually indicate calmer, darker or more spacious sound; higher values indicate denser, brighter spectral movement.

What SCPI is — and is not

SCPI is not BPM and does not try to identify genre. It is a reproducible measure of spectral colour pace, designed to complement conventional tempo information and help compare the texture and movement of music.

The public demo runs the same open-source SCPI tool available on GitHub.