Ubuntu has conventional tools to manage sound devices, as speakears, headphones and mics.
Alsamixer
It's a terminal-based tool directly attached to alsatools. You must open a terminal window and type alsamixer
:
Here you must press left and right to go trough components, up and down to change levels and M to mute/unmute them.
If your computer has more than one sound device, switch among them with F6
Pulseaudio Volume Control (pavucontrol)
pavucontrol is a GUI-based sound controller for alsa. You can install it by sudo apt install pavucontrol
. It gives you a better control of sources for your sound devices, changing best profiles to improve sound performance.