As members of an orchestra, we don’t happen to play “together” because we are in the same tempo, dictated by a conductor. Instead, we actually pay attention to each other, listen to whoever that has something to say, able to express ourselves because others would listen and allow you to speak. For example, the timpani does not start playing his part because he counted the correct number of blank measures, or because the conductor cued him. Instead, he continues the musical story that has been unfolding by others by knowing what has been told.
uosymphony
A resource for UO Symphony members and classical music lovers in the Eugene community
uosymphony 
This is a great way of looking at it. I very much enjoy being a part of an ensemble where this happens naturally, because it is usually frustrating when this unity is absent.