Would you dare say that audio and animation are separate from one another? One certainly can exist without the other. But I submit that they become so much tighter when the two work together. For example, if one were to write a song and build an animation at the same time, both aspects can and should lend to one another. I believe this because there are many similarities between both disciplines. Principles of animation could be applied to music, and theories of music could be applied to animation. Think about it. They both concern timing, pacing, and the good ones cycle between exciting action and relaxing room to breath.
I'll have a Flash piece concerning this theory very soon.