Playing a sound on hittest

Okay so i’m making this game, and I want it, so when the bar scrolls across the screen and hits the box it will play the sound inside the box mc.

The code I have inside the box with the sound is.

onClipEvent (enterFrame)
{
if (this.hittest(_root.trackline))
{
this.gotoAndPlay(“sound”);
} // end if
}