An orchestra conductor coordinates all the instrument members to think and perform collectively, according to the Los Angeles Times. Conductors do most of their work in training the musicians before a concert.
A good conductor puts his ego aside and encourages the members to exhibit their own energy and interpretation of the music while following his lead, according to the Los Angeles Times. A conductor individualizes the music, so that no two performances are the same. He may also implement changes during the course of a performance with his commands, such as changes in the musical phrasing. Orchestras that play without a conductor do well, but the performance often sounds mechanical, rather than interpretive.