[yumakar]

Каждое нажатие кнопки mute_btn чередует режимы mute и unmute.

mute_btn.addEventListener(MouseEvent.MOUSE_DOWN, mute);
var counter_mute = 0;
var mt = new SoundTransform();
function mute (event:Event):void {
counter_mute ++;
if(counter_mute > 1) {counter_mute = 0}
if(counter_mute == 1) {
mt.volume = 0;
soundChannel.soundTransform = mt};
if(counter_mute == 0) {
mt.volume = 1;
soundChannel.soundTransform = mt};
}