actionscript 3 - i have a soundTransform issue. -

I know that I'm missing some stupid I can give a hand? I'm trying to mute and make MCS invisible. I've done something wrong with soundtransform bit quite new on AS3

  Var is Playing MC: Movie Clip = MC1 ;; Var is placing MCcurrentFrame = 0; Var soundtrack: Soundtrafficform = new soundtrafficform (); SoundTr.volume = 1; Btn1.addEventListener (MouseEvent.CLICK, playMC1); Function Playmc 1 (E: Mouse Event): Zero {isPlayingMCcurrentFrame = isPlayingMC.currentFrame; IsPlayingMC = MC1; IsPlayingMC.gotoAndPlay (isPlayingMCcurrentFrame); Mc2.volume = 0; Mc3.volume = 0; Mc3.visible = false; Mc2.visible = false; Mc1.visible = true} btn2.addEventListener (mouse Event.click, Playmc2); Function Playmc2 (E: MouseEvent): Zero {isPlayingMCcurrentFrame = isPlayingMC.currentFrame; IsPlayingMC = MC2; IsPlayingMC.gotoAndPlay (isPlayingMCcurrentFrame); Mc1.volume = 0; Mc3.volume = 0; Mc1.visible = false; Mc3.visible = false; Mc2.visible = true} Btn3.addEventListener (Mouse EventPaste, Playmcry3); Function Playmc3 (E: Mouse Event): Zero {isPlayingMCcurrentFrame = isPlayingMC.currentFrame; IsPlayingMC = MC3; IsPlayingMC.gotoAndPlay (isPlayingMCcurrentFrame); Mc1.volume = 0; Mc2.volume = 0; Mc1.visible = false; Mc2.visible = false; Mc3.visible = true}    
 
 
 You actually get your  SoundTransform  To  movie clips  s because they do not have a simple  quantity  property:  
  var st1: SoundTransform = new SoundTransform (); St1.volume = 0; Mc1.soundTransform = st1;   
 Relevant Reference Document.