hitTest & for - speed problem

programming flash
1

I am building something where I need to do this:

http://www.starvingeyes.com/pepsijazz/add6.html

The lines are drawn using curveTo code and will eventually wave all over the place. The bottome line, is actually a fill with the alpha set to 0. In order to get the notes that fly along to hug the bottom line. I do something like this:


name.startyy = 600;
for (yy=name.startyy, go=true; yy>200 & go == true; yy -= 1) {
    xx = name._x;
        if (root.line1.hitTest(xx, yy, true)) {
            name._y = yy
            go = false;
        }
    }

The problem is that when I have to many notes on screen at the same time doing this code, it slows down. Is there a way to figure out where the notes should go that will make the movie run faster?

PLEASE VISIT LINK ABOVE BEFORE RESPONDING.

Thank you!