I upgraded my old visualizer, so I can now visualize any audio in real time, wich is playing on my PC. The visualization depends a bit on the loudness of your audio and is slightly different from the other visualisation where you have to choose a file.
I accomplished that with the CsCore library. (https://archive.codeplex.com/?p=cscore)
Download: https://acetix.itch.io/music-visualizer
I've made the "old" visualizer with the help of PeerPlays tutorials. Here's a link to his channel: / @peerplay