Sonic-Visualiser is also a GUI based tool. It is similar to Audacity but a bit more powerful than it. It is an application software for viewing and analysing the contents of audio files.
Sonic Visualiser is available for Linux, OS/X, and Windows. You can download Sonic-Visualiser from its offical site, or in Ubuntu, you can download it from the Ubuntu store.
Sonic-Visualiser can be used from the command line or by directly clicking the icon in applications.
$ sonic-visualiser <file_name>
Similar to Audacity, Sonic-visualiser also has a feature of changing layers like spectrogram. To do that, go to layer option in the option menu. You can find so many features like spectrogram and some more features like changing the speed of the audio etc, by clicking the "playback" option in the option menu. We can view the morse code etc.
Finally, after analysing both Audacity and Sonic-Visualiser, Sonic-Visualiser has more flexibility of revealing the data in audio files.
Sonic visualiser reveals more information which can't be shown in the audacity also. Look at this example,
When a file was opened in Audacity under spectrogram,
When the same file was opened using sonic visualiser under spectrogram,
In this way, sonic visualiser reveals the information present in the audio files.
Visit its Documentation.