Spek (IPA: /spɛk/, ‘bacon’ in Dutch) helps to analyse your audio files by showing their spectrogram. Spek is free software available for Unix, Windows and macOS.


  • Supports all popular lossy and lossless audio file formats thanks to the FFmpeg libraries.

  • Ultra-fast signal processing, uses multiple threads to further speed up the analysis.

  • Shows the codec name and the audio signal parameters.

  • Allows to save the spectrogram as an image file.

  • Drag-and-drop support; associates with common audio file formats.

  • Auto-fitting time, frequency and spectral density rulers.

  • Adjustable spectral density range.

  • Translated into multiple languages.


Spek running on Ubuntu, Windows and macOS


Spek is free and open source software licensed under GPLv3. The project is written in C++, the code is available on GitHub.

Report bugs and request new features on the issue tracker.

Translation is done via Transifex. Don't hesitate to translate Spek into a new language or to improve existing translations.

Thanks for using Spek! Subscribe to receive updates and support my work.

Subscribe to Spek — Acoustic spectrum analyser

Free / open source spectrogram viewer available for GNU/Linux, Windows and macOS.