Rule of the octave for melody

Introduction

The Rule of the Octave is a musical concept that originated in the practice of thorough bass or basso continuo. It provides a systematic approach to harmonizing melodies by determining which chords can accompany each note of the scale in the bass. This article explores the origin, description, and harmonization variants of the Rule of the Octave, focusing on its application in melody.

Origin and Description

The Rule of the Octave traces its roots back to the 18th century and was first described by Antonio Bruschi in 1711. The name “Rule of the Octave” was later given by François Campion in 1716. It served as a fundamental principle in the “regole” (rules) of partimento collections, providing a framework for harmonizing melodies.

Harmonization Variants

The Rule of the Octave offers different harmonization approaches for ascending and descending bass lines. While it is referred to as a rule, there are several variants with different chord progressions. Additionally, distinct versions of the Rule of the Octave exist for major and minor scales, accommodating the tonal characteristics of each.

Major Scale Harmonization

Ascending

When harmonizing a major scale using the Rule of the Octave in ascending order, specific chord configurations are employed:

• Scale degrees ➀ and ➄ receive a root position triad (5/3).
• Most other notes of the scale receive a first position triad (6/3).
• Exceptions include the 6/4/2 chord on the descending ➃.

Descending

When harmonizing a major scale in descending order, the following chord arrangements are used:

• Scale degree ➇ receives a root position triad (5/3).
• Scale degree ➆ receives a first position triad (6/3).
• Exceptions include the ♯6/3 or ♯6/4/3 chord on the ascending ➅.

Minor Scale Harmonization

Ascending

When harmonizing a minor scale using the Rule of the Octave in ascending order, the following chord progressions are applied:

• Scale degrees ➀ and ➄ receive a root position triad (5/3).
• Most other notes of the scale receive a first position triad (6/3).
• Exceptions include the ♯6/4/3 chord on the ascending ➁.

Descending

When harmonizing a minor scale in descending order, the following chord configurations are utilized:

• Scale degree ➇ receives a root position triad (5/3).
• Scale degree ♭➆ receives a first position triad (6/3).
• Exceptions include the ♯6/4/3 chord on the ascending ➅.

Sources

• OPEN MUSIC THEORY – Rule of the Octave
• Wikipedia – Rule of the Octave
• Music: Practice & Theory Stack Exchange – What chords does Rule of the Octave use?

FAQs

What is the Rule of the Octave?

The Rule of the Octave is a musical concept that originated in the practice of thorough bass or basso continuo. It provides a systematic approach to harmonizing melodies by determining which chords can accompany each note of the scale in the bass.

Who first described the Rule of the Octave?

The earliest description of the chords harmonizing an octave can be traced back to Antonio Bruschi in 1711. The name “Rule of the Octave” was given by François Campion in 1716.

Are there different harmonization variants of the Rule of the Octave?

Yes, there are different harmonization variants for ascending and descending bass lines. Although called a rule, there are several variants with different chord progressions. Different versions for major and minor scales are also recorded.

How is the Rule of the Octave applied to harmonize a major scale?

In the Rule of the Octave for harmonizing a major scale:

• • Ascending:
    • • Scale degrees ➀ and ➄ receive a root position triad (5/3).
    • • Most other notes of the scale receive a first position triad (6/3).
    • • Exceptions include the 6/4/2 chord on the descending ➃.

• • Descending:
    • • Scale degree ➇ receives a root position triad (5/3).
    • • Scale degree ➆ receives a first position triad (6/3).
    • • Exceptions include the ♯6/3 or ♯6/4/3 chord on the ascending ➅.

How is the Rule of the Octave applied to harmonize a minor scale?

In the Rule of the Octave for harmonizing a minor scale:

• • Ascending:
    • • Scale degrees ➀ and ➄ receive a root position triad (5/3).
    • • Most other notes of the scale receive a first position triad (6/3).
    • • Exceptions include the ♯6/4/3 chord on the ascending ➁.

• • Descending:
    • • Scale degree ➇ receives a root position triad (5/3).
    • • Scale degree ♭➆ receives a first position triad (6/3).
    • • Exceptions include the ♯6/4/3 chord on the ascending ➅.

Can the Rule of the Octave be applied to other scales?

The Rule of the Octave is primarily used for major and minor scales. However, the concept of harmonizing melodies based on the scale degrees in the bass can be adapted to other scales as well.

Is the Rule of the Octave a strict rule or are there variations?

While the Rule of the Octave is referred to as a rule, there are variations with different chord progressions. These variations allow for flexibility and creativity in harmonizing melodies.

How can I learn and apply the Rule of the Octave in my own compositions?

To learn and apply the Rule of the Octave in your compositions, it is recommended to study and analyze examples of its application in different musical pieces. By understanding the principles and variations of the Rule of the Octave, you can experiment with harmonizing melodies and develop your own unique musical style.