Understanding Altered Chords in Music Theory and Practice: A Comprehensive Guide

When delving into music theory, especially within the realm of jazz and improvisation, it's crucial to understand the nuances of altered chords. These chords carry rich harmonic implications and offer flexibility in both theoretical and practical music-making scenarios. In this guide, we will explore the concept of altered chords, their components, and how to apply them effectively in real-world settings.

The Concept of Altered Chords

Altered chords are a combination of a dominant seventh chord and additional outside tensions. They are often used in jazz and other complex musical genres to add complexity and interest to the harmonic progression. While the theory of chords might seem straightforward in a classroom setting, practical application often requires a more flexible interpretation.

The Classroom vs. Real-Life Application

In a classroom, the notation of a chord like C13b9#11 is meant to denote each individual note stacked from the root to the 13th. However, in a real-life musical performance, it's highly unlikely that all these notes will be played simultaneously on a single instrument. The chord symbol serves as a guideline, implying that these notes could theoretically be played, but not necessarily all at once. When improvising, jazz musicians often skip certain notes, and this is commonly referred to as "change running."

Voicing Practice

In performance, a chord player typically leaves the root to the bass player, unless there isn't one. Instead, the chord player focuses on voicing the third and seventh, along with potentially one or two additional notes. The voicing in thirds is not strictly required; in fact, some players might dispense with the third and seventh if the chord lasts for an extended period. As tensions like the eleventh and thirteenth imply the third and seventh, respectively, these can be omitted without losing essential harmonic information.

Understanding Altered Chords in Depth

Altered chords are constructed using outside tensions from the altered scale. Typically, the notation involves using negative signs to denote alterations, such as -9, b9, 5, and b5. To determine the specific tensions in a chord, one must specify which outside tensions are included. For example, a G7 chord with an altered 9 and b13 would be denoted as G7b9b13.

Standard Altered Chord Notations

Often, the term "alt" is used to denote the presence of a 5. Therefore, a G7 chord with all possible tensions is written as alt7. Other notations include:

A typical altered chord notation alt dom - R b9 9 b5 5 b7 breaks down the chord's properties, highlighting the scale it derives from.

Chords from Different Scales

Altered chords can come from various scales:

These scales provide different outside tensions, resulting in various chordal combinations:

By considering these scales and their tensions, one can better understand how to interpret and apply altered chords in a musical context.

Conclusion

Understanding altered chords is essential for any musician, especially those focused on jazz or complex harmony. While the theory provides a framework, practical application often requires adaptability. By considering the different scales and tensions, musicians can create richer, more intricate harmonies that enhance their musical performances.