HP Notebook - Manual (Page 84)

Multimedia
Adjusting Volume
Volume can be adjusted by using the audio buttons on the
notebook or by using operating system or application volume
control software. The mute button overrides all software
volume settings.
To adjust volume using the audio buttons:
To increase volume, press the increase volume button 1.
To decrease volume, press the decrease volume button 2.
To mute or restore volume, press the mute button 3.
When volume is muted, the mute light 4 turns on. When volume
is restored, the mute light turns off.
Identifying the audio buttons and mute light
6-2 Startup and Reference Guide––Part 2