---
title: "Parallel Motion — AP Music Theory Definition & Exam Guide"
description: "Parallel motion is when two voices move the same direction by the same interval. Learn how it's tested in AP Music Theory part writing and why parallel 5ths fail."
canonical: "https://fiveable.me/ap-music-theory/key-terms/parallel-motion"
type: "key-term"
subject: "AP Music Theory"
---

# Parallel Motion — AP Music Theory Definition & Exam Guide

## Definition

Parallel motion occurs when two or more voices or musical lines move in the same direction by the same interval. This type of motion can create a sense of unity and consistency in harmony, but it can also lead to dissonance if not used carefully. In music theory, understanding parallel motion is essential when analyzing voice leading and harmonic progressions, especially with chords such as cadential 6/4.

## Related Study Guides

- [4.1 Harmony and Voice Leading I](/ap-music-theory/unit-4/harmony-voice-leading-i/study-guide/0m8OiGeqjebWSd6bMZ0W)
- [Unit 4 Overview: Harmony and Voice Leading I (Chord Function, Cadence, and Phrase)](/ap-music-theory/unit-4/review/study-guide/DLvyy0BGFPsF3AJEN9Fr)
- [5.6 Cadential 6/4 Chords](/ap-music-theory/unit-5/cadential-64-chords/study-guide/Fmolx6ik4nmpMVO4inHe)

## Review

### Related Terms

- Contrary Motion: Contrary motion happens when two voices or musical lines move in opposite directions, which helps create contrast and independence between the parts.
- [Oblique Motion](/ap-music-theory/key-terms/oblique-motion): Oblique motion occurs when one voice stays on the same pitch while another moves, which can help maintain harmonic support without losing melodic interest.
- [Voice Leading](/ap-music-theory/key-terms/voice-leading): Voice leading is the practice of writing smooth, coherent transitions between chords in a piece of music, ensuring that each voice moves efficiently from one note to the next.

### Key Facts

- In parallel motion, if voices are moving in parallel thirds or sixths, they tend to sound more consonant and cohesive, which can enhance the overall harmonic texture.
- Parallel fifths are generally discouraged in traditional Western music because they can weaken the independence of voices and create a hollow sound.
- When using parallel motion with cadential 6/4 chords, it's important to resolve them properly to avoid dissonance that could disrupt the flow of the harmony.
- Different types of parallel motion can influence how we perceive tension and resolution within a piece, as certain intervals will evoke different emotional responses.
- Composers often use parallel motion intentionally for stylistic effects, especially in genres like chorale or hymnal writing, where uniformity is desired.

### How does parallel motion contribute to the overall texture of a musical piece?

Parallel motion enhances the overall texture of a musical piece by creating a sense of unity among the voices. When voices move together in parallel intervals, such as thirds or sixths, they blend harmonically and strengthen the sound. However, it's crucial for composers to be mindful of the intervals used, as excessive use of parallel fifths can lead to less independence among the voices and potentially weaken the music's harmonic structure.

### Discuss the implications of using parallel motion in the context of cadential 6/4 chords.

Using parallel motion with cadential 6/4 chords is a delicate balancing act. While this technique can emphasize the resolution and strengthen harmonic progression, it must be handled carefully to avoid creating dissonance. A cadential 6/4 typically resolves to a dominant chord, and maintaining proper voice leading through careful use of parallel intervals can ensure smooth transitions and reinforce harmonic goals without sacrificing clarity.

### Evaluate the role of parallel motion in voice leading and how it affects harmonic progressions in various musical styles.

Parallel motion plays a significant role in voice leading by influencing how chords connect and flow into one another. In styles like Baroque or Classical music, where clarity and coherence are essential, effective use of parallel motion ensures that voices maintain their independence while contributing to a cohesive harmonic structure. However, in more contemporary genres, composers may manipulate parallel motion creatively to evoke specific emotions or stylistic nuances, challenging traditional norms while still relying on fundamental principles of harmony and voice leading.