Root of my PinSound One USB drive
Contents of my config.ini file
You will have to play with the ducking settings (remove the leading semi-colon to enable them). Values are 0-100. I assume PinSound has left this feature available in their latest firmware, and I also assume it works on PinSound Plus.
If your config.ini has coded characters in it, then my recommendation is to copy the file off somewhere or rename it, then create a new config.ini with the contents as I've shown. Give it a try, can't hurt anything.