Sound slider and volume tutorial?

im having problems makin a volume slider…


//----------------------------------------
loader.scrub.left = loader.scrub._x;
loader.scrub.right = loader.scrub.left+100;
loader.scrub.top = loader.scrub._y;
loader.scrub.bottom = loader.scrub._y;
loader.scrub._x = playerSound.getVolume();


volume_txt.text = playerSound.getVolume();
loader.scrub.onPress = function() {
    this.startDrag(false, this.left, this.top, this.right, this.bottom);
    this.isDragging = true;
};
loader.scrub.onMouseMove = function() {
    if (this.isDragging) {
        volume_txt.text = this._x;
    }
};
loader.scrub.onRelease = loader.scrub.onReleaseOutside=function () {
    stopDrag();
    isDragging = false;
    playerSound.setVolume(this._x);
};
//----------------------------------------

the volume keeps being displayed as 43 to 143
or -173 to 21 depending where I put the MC on the stage

what am i doin wrong?