Twitch music too quiet in the stream?

I have the problem that the music is much quieter when streaming than I hear it myself. I set it to 25% in the VLC player, which is already relatively loud, but in the stream it is very quiet. Can I somehow balance this? I use Streamlabs OBS.

The audio for the stream is mixed separately in the audio mixer from OBS or also at Streamlabs OBS. There you can manually set the desktop audio for the stream. The mixer is located next to the sources.