On 16.02.21 19:16, nik(a)parkellipsen.de wrote:
  So, my idea would be to have a mixer in JACK that
allows me to mix my voice and
 the streaming audio before it goes into discord (via the PulseAudio JACK Source),
 and in addition allows me to put a compressor on the mix so that the streaming
 audio and my voice will be at a good level.
 Does anybody have a hint what could be a good tool here ? 
Maybe 
https://github.com/jack-mixer/jack_mixer