musicbtn.addEventListener(MouseEvent.CLICK, fl_ClickToPlayStopSound);

var fl_SC:SoundChannel;

var fl_ToPlay:Boolean = true;

function fl_ClickToPlayStopSound(evt:MouseEvent):void

{
if (fl_ToPlay)

{
    var s:Sound = new Sound(new URLRequest("sound/music1.mp3"));
    fl_SC = s.play();
}
else
{
    fl_SC.stop();
}
fl_ToPlay = !fl_ToPlay; }

var s:Sound = new Sound();
s.addEventListener(Event.COMPLETE, completeHandler); // not entirely sure this is the correct event, but it should be. I haven't played with the Sound class in a while
s.load(new URLRequest("sound/music1.mp3"));

function completeHandler(e:Event):void {
    var fs:FileStream = new FileStream();
    var f:File = File.applicationStorageDirectory.resolvePath("music1.mp3"); // selects file in the sandboxed dir for your app

    var bytes = new ByteArray();
    s.extract(bytes, 4096); // load file into ByteArray. Unsure length argument is correct, may need tweaking

    fs.open(f, FileMode.WRITE); // opens stream to file, sets mode to WRITE which will create and truncate the file
    fs.writeBytes(bytes); // write ByteArray to file
    fs.close(); // closes link to file. ALWAYS make sure you do this. Failing to do so can have consequences
}

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

var soundfile:File = File.applicationStorageDirectory.resolvePath("music1.mp3");
var fstream:FileStream = new FileStream();
fstream.open(soundfile, FileMode.WRITE);
fstream.writeBytes(ba, 0, ba.length);
fstream.close();

ByteArray ba;
sound.extract(ba, 4096);