hi, while debugging my sound setup in Xubuntu 18.4, I came up on some strange behaviour. Reason for debugging was, I couldn't play rear line input to line output. To check, if I missed some basic settings I started alsamixer.

As I always do, I toggled each setting, to make sure, that the displayed status reflects it's actual state. This routine is one relict from my old windows times :-)

When I applied this method to "loopback", which initially was displayed as "enabled" ( switch from enabled to disabled and back to enabled), I instantly got sound output. This can, and must be, reproduced after every restart of the desktop.

Sorry, if I posted this mail wrong way, wrong place, but I thought, the observation might be of interest.

Jochen