From Quake Wiki
|Saved to config.cfg:||yes|
This is the master volume for all sounds in the game. The range is 0 to 1, with zero being no sound and 1 being full volume. Do not set above 1 or below 0 or the game may crash. This is particularly useful to QuakeC programmers in the event you want to fade out the sound, often times fading simultaneously with v_cshift.
|List of console variables | List of console commands|