How to lower the volume from minimserver

[gloubibulles]

hello
Indeed, I've tried this option in the Lumin app to reduce the analog audio output level (-4ds indeed), but it's not enough... the sound is still very loud :-(
I could use the volume control of the Lumin app to reduce it, but I've noticed that the quality is not as good when disabled (100 out of 100)
that's why I wanted to know if there's a way to have Minimserver "do the job" instead of the Lumin... Is there any code to have Minimserver reduce the gain of the files it sends to the Lumin via my Synology Nas?
thanx again for your help