# `mix mx.spectrogram`
[🔗](https://github.com/mx-music/mx/blob/main/lib/mix/tasks/mx.spectrogram.ex#L1)

Draws a spectrogram of a WAV or AIFF recording into a PNG image, with seconds across and octaves up the side.

    mix mx.spectrogram Guitar.mf.sulA.A2B2.aif
    mix mx.spectrogram Guitar.mf.sulA.A2B2.aif --out a-string.png

The image is written beside the recording with the extension .png unless `--out` names it.

    mix mx.spectrogram "cuica (2).wav" solo.wav --from 1 --seconds 2.4 --per-second 400 --window 4

Several recordings are drawn into one image, one above another from the first, beside which the image is written, each against its own loudest point, so a synth's render can be compared with a recording moment by moment.
`--from` and `--seconds` draw only a stretch of each recording, from a second and for so many seconds.
`--per-second` is the pixels a second takes across, 100 unless given.
`--window` is the milliseconds of sound in each column, 4096 samples unless given: a long window tells the harmonics apart, and a short one, such as 4, shows how the level moves within a note and where notes join.

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*Consult [api-reference.md](api-reference.md) for complete listing*