About
Lightweight, open-source acoustic spectrum analyser that draws a spectrogram of an audio file.
Spek opens an audio file and renders its spectrogram: frequency on the vertical axis, time on the horizontal axis and level as colour. It is commonly used to check whether a file is genuinely lossless or has been transcoded from a lossy source, because lossy encoders typically cut high frequencies above a visible threshold.
It decodes audio with FFmpeg, so it reads most formats, and it runs on Windows, macOS and Linux. Spek is free software under the GPL 3.0.
Features & Use Cases
- Spectrogram of any audio file
- Reads most formats via FFmpeg
- Useful for checking lossless vs transcoded files
- Open source (GPL 3.0)
Pricing
Free and open source.
View current pricingSources
Pricing checked 3 October 2026. Preview from substackcdn.com, retrieved 3 October 2026.