SecurityError: Error #2121: Security sandbox violation: SoundMixer.computeSpectrum:

make sure your allowScriptAccess parameter is set to always.

there's no problem with computeSpectrum working with a sound playing via a loaded as2 swf.

there aren't any references to any other files..

but I thing that the soundSpectrum automatically 'reads' all audio events from the other swf and any other window......

here is the code from the swf

var s:Sound = new Sound(new URLRequest("Dynamic_Full_Track_64.mp3"));
/*s.play(0, 1000);*/

var ba:ByteArray = new ByteArray();

/*var square:Sprite = new Sprite();
addChild(square);*/



addEventListener(Event.ENTER_FRAME, loop);

function loop(e:Event):void
{
graphics.clear();
graphics.lineStyle(2, 0x5AA426);
graphics.moveTo(-1, 37);
SoundMixer.computeSpectrum(ba);
for(var i:uint=0; i<256; i++)
{
var num:Number = -ba.readFloat()*28 + 35;
graphics.lineTo(i*1.375, num);
}
}

what code in your as3 file is trying to access your as2 file?