Your example is wrong, I think: My eyesight can't tell me about the truck around the corner and I only know it when I hear it but that doesn't mean that I can s

Your example is wrong, I think: My eyesight can't tell me about the truck around the corner and I only know it when I hear it but that doesn't mean that I can see it next time. In comparison, when you "see" the polyphony you are one step closer to "hearing" it the next time.