Can someone explain to me exactly how this works? It's not the oscilloscope producing the sounds, correct? Rather the visualizations from an audio file?
The left and right channels are connected to the oscilloscope's X and Y input.
The left and right audio channels are connected to two oscilloscope inputs to control the X and Y deflection of the trace. Think of animated Etch-A-Sketch using music.
Most scopes have a 1kHz square wave signal output for calibration, surely all you need then are 20 filter boxes or so.