sound spectrum as3

I have   the following  as3 code

var url:String = "song.mp3";

var request:URLRequest = new URLRequest(url);

var s:Sound = new Sound();

s.load(request);

var song:SoundChannel

var ba:ByteArray = new ByteArray();

var gr:Sprite = new Sprite();

gr.x = 20;

gr.y = 200;

addChild(gr);

song = s.play();

var isPlaying:Boolean = false;

gr.addEventListener(MouseEvent.CLICK, togglePlay);

function togglePlay(e:MouseEvent):void

{

    if (!isPlaying)

    {

song = s.play();

addEventListener(Event.ENTER_FRAME, loop);

    }

    else

    {

song.stop();

removeEventListener(Event.ENTER_FRAME, loop);

    }

    isPlaying = !isPlaying;

}

addEventListener(Event.ENTER_FRAME, loop);

function loop(e:Event):void {

    SoundMixer.computeSpectrum(ba, true);

    var i:int;

    gr.graphics.clear();

    gr.graphics.lineStyle(0, 0xFF0003);

    gr.graphics.beginFill(0xFF0003);  

    gr.graphics.moveTo(0, 0);

    var w:uint = 2;

    for (i=0; i<30; i+=w) {

        var t:Number = ba.readFloat();

        var n:Number = (t * 10);

        gr.graphics.drawRect(i, 0, w, -n);

    }

}

when  i  execute the  code. the  spectrum  stops but song  continues to  play. What i want is when i click on the spectrum  ,both the spectrum and the song stops .When i  click again on the spectrum both song and  spectrum resumes to  play.

please help

rakesh