There are many different ways to skin a cat here is an example of a slightly more bloodier version:

Code:
var mySound:Sound = new MySound();
var mySoundCHNL:SoundChannel = new SoundChannel();
mySound= mySound.play(0,1000);
var mySoundVolume:SoundTransform = mySoundCHNL.soundTransform;
mySoundVolume.volume = 0;
volume can be set from 0 to 1.

MySound is a sound file in the library as a class linkage