"Sound in air is the transfer of periodic movements between adjacent colliding atoms or molecules."
The energy
usually expands away from source of vibration. Though most
physics textbooks will tell you sound travels in waves, it
is more accurate to compare them to an expanding sphere in
air which moves in all directions. When sound is
represented spherically, cymatics can be used to study the
mechanics of sound on different frequencies with different
materials. Though in more common cases, sound is in no way
visual to us. I
f you saw
someone singing in the shower, you wouldn't be thinking
about the atoms and molecules bumping into each other
creating periodic motions, you would be thinking how awful
they sound and that they really shouldn't do that in
public. However, if we were able to perceive sound, that
same voice would create a beautiful, unique, shimmering
bubble of sonic energy bursting from their open mouth. 
So what else would this look like? It's proposed that electromagnetism created by sound lay in about the infra-red to radio frequency spectrum, so we would be seeing colors we've never experienced. Imagine that, a classical concert filled with pretty colors and complex geometry emitting all over the concert hall. Music would be a completely different experience.
http://blog.world-mysteries.com/science/cymatics/