It's a really great project, and it is funny how the origin of the idea is the same that the one of my project: show what a loop is through the rotation of a circle.
This made me think though: it could be possible to really simplify this object to offer a simple replacement turntable arm which could instantly transform any turntable into a graphic beatbox.
Using a reflectance sensor array linked to an arduino which would output different sounds anytime a sensor is detecting a reflectance spike would be enough!
It would work kind of like this graphic robot! (you can "program" it by drawing on control disks, kind of the same way we use to program computer with punch cards)
No, real programmer draw on a disc!