Lock DSP volume - only use headunit volume

[Andre]

For sure, just uncheck the option "fix radio volume" in DSP settings.
Check wiki for this: https://wiki.ibus-app.de/index.php?title...riebsarten

And if I may guess: you're using an elongation from trunk to radio? So please try an additional ground wire (1-2,5mm€) between radio and car chassis to reduce the noise. ;-)