As is remarked away back in the Catalog 3 comments, this might be a reference to the condition synaesthesia, a sort of "crossing" of senses, where an auditory stimulus can cause a visual sensation. There are some synaesthetic artists, inspired to paint an impression of what they see when hear a piece of music, for example. In view of the fact that there is also a Catalog 3 track called Visual Drone 12, this is the view favoured by [DC].