How to garbage collect an newed as3 Sound Object from memory?

Question

For example, using next text code:
package
          import flash.display.*;
          import flash.events.*;
          import flash.media.*;
          import flash.system.*;
          import flash.system.*;
          public class Main extends Sprite
                    [Embed(source = "../data/SongScene8.mp3")] protected var SongScene8:Class;
                    public function Main():void
                              if (stage) init();
                              else addEventListener(Event.ADDED_TO_STAGE, init);
                    private function init(e:Event = null):void
                              removeEventListener(Event.ADDED_TO_STAGE, init);
                              System.gc();
                              trace("Before");
                              trace(System.totalMemory);
                              trace("_________________")
                              var sound:Sound = new SongScene8();
                              System.gc();
                              trace("After new");
                              trace(System.totalMemory);
                              trace("_________________")
                              sound = null;
                              System.gc();
                              trace("After null");
                              trace(System.totalMemory);
The output is:
Before
3461120
After new
3604480
After null
3604480
* Even if the gc runs a thousand times after, the last, increased value remains.
* I've tested this too by importing an mp3 from an .swc, rather than from a file. The result is similar.
* Tracing System.privateMemory rather than System.totalMemory gives similar (although offset) results.
Wether or not a soundchannel is played on it, it looks like the Sound Object
cannot be removed from memory.
Please say I'm wrong and tell me why.
Thanks in advance

Answer 1

works for me in cs5.5:
Loop 1
Before
28780
sound created
28796
After null 0
29380
After null 1
29196
After null 2
29192
After null 3
29192
Loop 2
Before
29192
sound created
29208
After null 0
29196
After null 1
29196
After null 2
29196
After null 3
29196
Loop 3
Before
29196
sound created
29208
After null 0
29196
After null 1
29196
After null 2
29196
After null 3
29192
Loop 4
Before
29192
sound created
29204
After null 0
29192
After null 1
29192
After null 2
29192
After null 3
29192
Loop 5
Before
29192
sound created
29204
After null 0
29192
After null 1
29192
After null 2
29192
After null 3
29192
Loop 6
Before
29192
sound created
29204
After null 0
29192
After null 1
29192
After null 2
29192
After null 3
29192
Loop 7
Before
29196
sound created
29208
After null 0
29196
After null 1
29196
After null 2
29196
After null 3
29196
use a frame loop to repeatedly execute the following and verify no memory leak:
var loops:int;
loops++;
if(loops>6){
    stop();
} else if(loops==1) {
    var s:String = "";
s+="Loop "+loops+"\n";
s+="Before\n";
s+=System.totalMemory/1024+"\n";
var sound:Sound = new SongScene8();
s+="sound created\n";
s+=System.totalMemory/1024+"\n";
var n:int;
clearF();
function clearF():void {
    n=0;
    sound=null;
    this.addEventListener(Event.ENTER_FRAME,f);
function f(e:Event):void {
    System.gc();
    s+="After null "+n+"\n";
    s+=System.totalMemory/1024+"\n";
    n++;
    if (n>3) {
        this.removeEventListener(Event.ENTER_FRAME,f);
        s+="_________________\n";
        if(loops>6){
            trace(s);