Install cairo-dock-alsamixer-plug-in by entering the following commands in the terminal:
sudo apt update sudo apt install cairo-dock-alsamixer-plug-in
Description:
Alsamixer plug-in for Cairo-dock
A collection of official plug-ins and applets for cairo-dock. . This plug-in lets you control the sound volume from the dock. This works with the Alsa sound driver.
Homepage: http://www.glx-dock.org/
Version: 3.4.1-2build1
Section: universe/x11