On my home stereo I have a spectrograph that has a 2D matrix, whereby the X axis is the frequency (deep bass on the left, vocals in the center, treble on the right), and the Y axis is the volume or power of the sound at that frequency. I have seen things like this for Ubuntu, but they work on MP3 files or other pre recorded songs. Is there anything that can do this real time for a microphone attached or simply the system mixer?


This may be a bit overkill, but Baudline is an incredible real-time FFT spectrogram. It's not in Ubuntu repos, so you will need to download it on your own. It displays a real-time analysys of source signal, but it also alows to analyse pre-recorded data. The brightness of a point represent the power of the sound at this frequency, where horisontal axis represents frequencies, and vertical time - so it kind of shows history of your signal.

It's extensive featrures make it definitelly the most advanced spectrogram available for Linux. It may be a bit too complicated for your uses, though. I am not sure what exactly you are looking for.

baudline screenshot


I've found two applications designed to analyze audio signals. The first one fullfills your requiremen



The JACK & ALSA Audio Analyser, an audio signal generator and spectrum analyser.



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 Mac OS X.

  • spek is great, I use it. – dotancohen Jun 1 '15 at 15:37
  • @juanpastas: I've tried to extend your answer, feel free to revert the changes. – Helio Sep 4 '18 at 21:01
  • I'm not sure that spek is an answer to the question, because I couldn't find an option to make it work in realtime. – a3nm Nov 5 '18 at 23:45

The sox tool is able to create a spectrogram:

sox Test.wav -n spectrogram -o Test.png
  • 2
    Could you edit your answer to provide a screenshot (just like other answers do) or a link to the product’s webpage or any information useful for someone who is trying to choose the right tool? – Melebius Sep 18 at 9:40

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