This CVar allows you to set the ambient volume (aka background sounds/noise) in-game.

If Sound_EnableAmbience is set to off, this cvar is ignored.

If the in-game chat is being used, this CVar is overridden by Chat_AmbienceVolume.

Default Setting

0.6

Possible Settings

This CVar accepts any number in a range from 0 to 1.0

0 

Ambient Sound off

1.0 

Ambient Sound full

Changing this setting

In-game, type the following

/console Sound_AmbienceVolume setting

Alternatively, you can exit wow, open the Config.wtf file, and add the following line:

SET Sound_AmbienceVolume setting

Patches

Patch 2.2.0 (25-Sep-2007): CVar name changed to Sound_AmbienceVolume due to settings for voice chat. 
Patch 1.1.0 (07-Nov-2004): Added as AmbienceVolume