Sight operates instantaneously. We see through medium of light and light is the fastest thing in the universe. It travels at 186,000 miles per second. Sound is relatively slow, moving at about 800 miles an hour. The difference between the speeds of light and sound symbolizes a fundamental difference between the two.
Sight perceives a complete whole instantaneously.
When we look at something, we perceive it at once as a complete entity. After this first sight, we may analyze what we are looking at in more detail, focusing on one element and then another, but the essence of vision is an instant whole. Sound, however, is always perceived as montage, a collage of different elements. We order these separate pieces of information to give them substance and definition, so that we may understand what it is we are hearing. This process of assembly is not instant.