Everything you see and hear is 100% real and all made by the laser beam interacting with the steel. Changes in the sizes of the rectangles make the different pitches. I know some notes are out of tune but it's the best the laser can do. This video is a composite of two separate videos - one for the bass and one for the melody. The end result is a plate with the finished logo. If I had two lasers next to each other I could make them play both parts together; but I don't.
Please excuse the harshness and tone of the audio. I am working on getting some better sound recording equipment due to the Automatic Gain Control of the camera's microphones. When there is a break in the music it amplifies the signal so you get to hear the background noise but once it starts playing again it is too loud and has to be backed off. Annoying.