Music is an aural art form.  Unlike language, which can be accurately communicated through the visual medium (text), looking at music notation doesn’t carry the same meaning as the actual sound of that piece.  Where an author’s work of art is in the text of the book, a musician’s art isn’t in the score, but the performance.

Human beings are visually oriented, though.  We take in most of our information about the world around us through our eyes.  We also have visual associations with sound (e.g., a dark timbre, a colorful chord).  Writing for Psychology Today’s blog, evolutionary neurologist Mark Changizi considers What Does Music Look Like To Our Brain?

Visual and auditory information interact in the brain, and the brain utilizes both to guess the single scene to render a perception of. For example, the research of Ladan Shams, Yukiyasu Kamitani and Shinsuke Shimojo at Caltech have shown that we perceive a single flash as a double flash if it is paired with a double beep. And Robert Sekuler and others from Brandeis University have shown that if a sound occurs at the time when two balls pass through each other on screen, the balls are instead perceived to have collided and reversed direction.

Changizi offers some other examples of research about visual and auditory processes in the brain, but I think he makes a couple erroneous assumptions.