MACROMEDIA FLEX-FLEX ACTIONSCRIPT LANGUAGE Reference page 702

Example
The following example uses two buttons,
sound that loads into a SWF file. Add two buttons to your document and add the following
ActionScript to your FLA or AS file:
var my_sound:Sound = new Sound();
my_sound.loadSound("song1.mp3", true);
stop_btn.onRelease = function() {
trace("sound stopped");
my_sound.stop();
};
play_btn.onRelease = function() {
trace("sound started");
my_sound.start();
};
See also
Sound.start()
702 Chapter 7: ActionScript for Flash
and
stop_btn play_btn
, to control the playback of a