Altered Scale: A Complete Music Theory Guide

what-is-an-altered-scaleThe altered scale, a fascinating and complex entity in the realm of music theory, stands as a cornerstone in jazz and contemporary composition for its rich harmonic possibilities.

This scale, derived from the melodic minor scale, is a vehicle for musicians to explore tension, dissonance, and resolution within their improvisations and compositions.

This guide delves into the altered scale, its structure, usage, and the creative avenues it opens for composers and improvisers alike.

What is an Altered Scale?

The altered scale is built on the seventh degree of the ascending melodic minor scale. It is unique in that it alters (sharpens or flattens) all possible notes except for the root and the 7th, leading to its other name, the Super Locrian scale.

The scale consists of the root, b2 (flat second), b3 (flat third), b4 (flat fourth) or #4 (sharp fourth), b5 (flat fifth), b6 (flat sixth) or #5 (sharp fifth), and b7 (flat seventh) intervals.

Structure and Formula

Given its derivation from the melodic minor scale, the altered scale can be viewed as a mode, specifically the 7th mode of the melodic minor.

For instance, the G altered scale is derived from the Ab melodic minor scale: G, Ab (b2), Bb (b3), Cb (b4/#4), Db (b5), Eb (b6/#5), F (b7), G.

Usage in Music

The altered scale is predominantly used over dominant 7th chords (V7) in minor key progressions, particularly when these chords are altered with b9, #9, #11, or b13 extensions. It introduces tension before resolving to the tonic, creating a sense of movement and complexity.

This makes the altered scale a favorite among jazz musicians for improvisation, as well as composers seeking a modern, sophisticated sound.

Alternate Names

The altered scale, a pivotal tool in jazz and contemporary music for its tension-rich sound over dominant chords, goes by several alternate names, each highlighting a different aspect of its theoretical underpinning or musical function:

Super Locrian Scale: This name emphasizes the scale’s position as the seventh mode of the melodic minor scale, where every degree except for the root and the 7th is altered (either raised or lowered). The “Super Locrian” descriptor highlights its deviation from the traditional Locrian mode by having an even more altered, or “super” altered, structure.

Diminished Whole Tone Scale: This name describes the scale’s unique construction, combining characteristics of the diminished scale (with its half-step, whole-step pattern) and the whole tone scale (built entirely of whole steps), particularly in the upper extension of the scale where it predominantly moves in whole steps.

Locrian ♯2 Scale: This variant emphasizes the raised second degree compared to the traditional Locrian mode, which has a flat second. The sharp two (or raised second) is a distinctive feature that differentiates it from the natural Locrian mode, making it a useful label for understanding the scale’s harmonic function.

Locrian ♭4 Scale: Less commonly, the altered scale may be referred to based on its flat fourth degree, a characteristic that further distinguishes it from the traditional Locrian mode and underscores its dissonant qualities.

Each of these names sheds light on a different aspect of the altered scale, from its theoretical origins to its practical applications, helping musicians and theorists understand and communicate its unique properties and uses in various musical contexts.

Altered Scale in Jazz Improvisation

Jazz improvisers use the altered scale to navigate chord changes, especially in tunes with rich harmonic progressions.

By incorporating the altered notes, musicians can highlight the tension over dominant chords, ensuring a smooth transition and resolution into either the tonic or the next chord in the sequence. The scale’s dissonant intervals offer a palette for creating solos that are both emotionally compelling and harmonically intriguing.

Compositional Techniques

In composition, the altered scale provides a tool for crafting harmonies and melodies that push the boundaries of traditional tonality.

Composers might employ the altered scale to develop themes or motifs that require a sense of instability or dissonance, often resolving these tensions in a manner that surprises and satisfies the listener. Its use in film scores and contemporary classical music underscores scenes or movements with complexity and depth.

Practice and Application

Mastering the altered scale requires practice and a deep understanding of its relationship to the underlying chord progressions. Musicians should begin by familiarizing themselves with the scale in all twelve keys, practicing slowly to internalize the unique intervals and sounds.

Integrating the scale into improvisation exercises over altered dominant chords can help in developing fluidity and creativity in using these tensions musically.


The altered scale represents a profound aspect of modern musical vocabulary, embodying the principles of tension and release that are central to the jazz idiom and beyond. Its ability to convey complexity, emotion, and resolution makes it an invaluable resource for musicians and composers aiming to enrich their harmonic and melodic language.

As with all aspects of music theory, the true power of the altered scale lies in its application—transforming notes and intervals into expressive, compelling music that resonates with both the player and the listener. Through study and practice, the altered scale becomes not just a scale but a pathway to deeper musical expression.

Frequently Asked Questions

How do altered scales differ from traditional major and minor scales in composition?

Altered scales incorporate sharpened or flattened notes that deviate from the traditional whole and half-step sequence of major and minor scales, introducing increased tension and dissonance. This unique structure makes them ideal for creating a sense of drama and anticipation, especially over dominant 7th chords in jazz and contemporary music.

Why are altered scales particularly favored in jazz improvisation?

Altered scales are favored in jazz improvisation because they provide a rich palette of tension-filled notes (like b9, #9, #11, and b13) that can be resolved in surprising and satisfying ways, offering a sophisticated sound that enhances the harmonic depth of solos over complex chord changes.

Can altered scales be used over any chord type in a progression?

Altered scales are most effectively used over altered dominant chords (V7 chords with altered extensions) to heighten tension before resolving to the tonic, as their dissonant intervals may not harmonically align with other chord types, such as major or minor chords, without careful application.

What are some effective practice strategies for mastering altered scales on an instrument?

To master altered scales, begin by learning and practicing the scale in all twelve keys, focusing on the unique intervals and how they create tension over dominant chords. Integrating these scales into improvisation exercises and applying them in the context of real music pieces or chord progressions can further develop your ability to use them creatively and musically.

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