Install alsamixergui by entering the following commands in the terminal:
sudo apt update sudo apt install alsamixergui
Description:
graphical soundcard mixer for ALSA soundcard driver
alsamixergui is an FLTK based mixer program for use with the ALSA soundcard drivers. It supports multiple soundcards with multiple devices. . alsamixergui is a frontend for alsamixer, written directly on top of the alsamixer source, leaving the original source intact, only adding a couple of ifdefs, and some calls to the gui part. It provides exactly the same functionality, but with a graphical user interface.
Homepage: http://www.iua.upf.es/~mdeboer/projects/alsamixergui/
Version: 0.9.0rc2-1-10
Section: universe/sound