The bass note of a chord or sonority is the lowest note played or notated. While the bass note is often the root or fundamental of the chord, it does not have to be, and sometimes one of the other pitches of the chord will be the root. In pre-tonal theory, root notes were not considered and thus the bass was the most defining note of a sonority. Most directors will want the bass note to play a little louder than any other single instrument, to provide a foundation for the chord.
