I get to relive those days all over again with my 3D printers - each stepper motor is controlled using a frequency - the frequency determines the speed and direction of the stepper motors. This creates quite a bit of music. Here's a video of some 3D printers in action, you can hear the whine of the motors in the background. Coincidentally, different types of 3D printers make different music. My cartesian coordinate printer sounds much like the oldschool 2D printers like the one above. But my delta 3d printer sounds like i've got a caged alien in the basement!
(These are my favorite looking 3D printers - so sexy to watch - but they sound pretty crazy, mine is a lot louder than this one)