Опять траблы со звуком

[MIX-er]

var my_sound:Sound = new Sound();
my_sound.onLoad = function(success:Boolean) {
	if (success) {
		my_sound.start();
		my_sound.setVolume(50);
	}
};
var my_sound1:Sound = new Sound();
my_sound1.onLoad = function(success:Boolean) {
	if (success) {
		my_sound1.start();
		my_sound1.setVolume(50);
	}
};
my_sound.loadSound("s1.mp3", false);
my_sound1.loadSound("s2.mp3", false);
//простейшая прослушка
var STEP:Number = 10;
var s1_vol:Number = 50;
var s2_vol:Number = 50;
var keyListener_obj:Object = new Object();
keyListener_obj.onKeyDown = function() {
	switch (Key.getCode()) {
	case Key.LEFT :
		s1_vol -= STEP;
		set_vol(s1_vol, s2_vol);
		break;
	case Key.UP :
		s2_vol -= STEP;
		set_vol(s1_vol, s2_vol);
		break;
	case Key.RIGHT :
		s1_vol += STEP;
		set_vol(s1_vol, s2_vol);
		break;
	case Key.DOWN :
		s2_vol += STEP;
		set_vol(s1_vol, s2_vol);
		break;
	}
};
Key.addListener(keyListener_obj);
function set_vol(s1_vol:Number, s2_vol:Number) {
	trace(s1_vol);
	my_sound.setVolume(s1_vol);
	my_sound1.setVolume(s2_vol);
}

и в чём трабля?