What are Parallel Octaves?

Parallel octaves occur when two musical voices move in the same direction while maintaining the interval of an octave between them from one note to the next. In this situation, if one voice moves up or down and the other voice moves in the same direction so that both notes remain exactly an octave apart, the motion is considered parallel octaves.

In traditional classical counterpoint and harmony, parallel octaves are generally avoided because they weaken the independence of the voices. Since the octave is one of the strongest and most consonant intervals, moving in parallel octaves can cause two voices to sound as if they are functioning as a single line rather than as separate melodic parts.

Although parallel octaves were restricted in Renaissance and Baroque counterpoint, they are sometimes used intentionally in modern composition, orchestration, and popular music to create a powerful or unified sound. When used deliberately, they can emphasize melodic strength or produce a bold, resonant texture.