Usually when we use a laptop, this type of equipment has keys with multimedia functions to control the volume of output through the speakers, but a conventional PC, with a conventional keyboard, this is not the case.
In my case, with Xfce I found a way to raise , lower , mute , and unmute the volume using amixer , which is simply a mixer for ALSA that is used via command lines. The commands I used in this case, along with the keyboard shortcuts, are listed below:
Turn up the volume:
command: amixer sset Master playback 5%+ with the keys: [Ctrl] + [+]
Volume Down
command: amixer sset Master playback 5%- with the keys: [Ctrl] + [-]
Put everything on Silent:
command: amixer sset Master mute with the keys: [Ctrl] + [*]
Activate the sound:
command: amixer sset Master unmute with the keys: [Ctrl] + [/]
I should clarify that Master is the channel to which I'm going to apply the options. As usual in Xfce , to configure these shortcuts we go to Menu » Preferences » Keyboard » Application Shortcuts , and it should look like the image.
Sure, you can use whatever shortcuts you prefer 