Attach sound AS problem

I’m trying to use the attach sound method when a Btn hits an MC one using this code but I’m not sure where to add the code. Can someone help me please? I want the sound to start when the Btn eases into the MC.


if (!dropZone.hitTest(this)) {
        this.onEnterFrame = function() {
            this._x += (this.startX-this._x)*speed;
            this._y += (this.startY-this._y)*speed;
if (this._x<this.startX+1 && this._x>this.startX-1 && this._y<this.startY+1 && this._y>this.startY-1) {
                this._x = this.startX;
                this._y = this.startY;
                delete this.onEnterFrame;