Understanding and Utilizing Altered Dominant Seventh Chords in Jazz Music
Chords form the backbone of music, especially in genres like jazz where complex harmonic structures are the norm. Among these, the altered dominant seventh chord stands out due to its powerful and dynamic nature. This chord, often represented as V7alt in chord symbols, is a rich source of tension and resolution in jazz progression.
What is an Altered Dominant Seventh Chord?
An altered dominant seventh chord is a specific type of seventh chord, typically a dominant seventh (e.g., C7, with the notes C, E, G, and B?), where one or more of the chord tones are altered. These alterations involve raising or lowering certain chord tones, usually the fifth, ninth, or sometimes the third. The Wikipedia article citing Noah Baerman emphasizes that the four commonly used alterations are the 5th, 9th, and both the sharp and flat ninth positions. This process significantly enhances the chord's expressiveness and adds a greater sense of tension and release in the resolution.
Common Altered Alterations in Jazz
When jazz players refer to an altered dominant seventh chord, they are most often discussing alterations of the fifth. This is in contrast to the ninth, which is specifically denoted in chord symbols with either a flat (b9) or sharp (#9) sign. For instance, if a jazz player indicates a chord as C7?9, it means the ninth is altered to a sharp ninth, rather than a simple C7 with alterations to the fifth only.
Performance Traditions and Altered Chords
While jazz chords can seem complex, understanding the harmonic tradition of a piece is crucial for the correct interpretation. The "alt" symbol in chord notation, however, can sometimes be ambiguous, as it does not a priori specify whether the fifth should be raised or lowered. It falls on the musician to determine the performance tradition, which can be challenging even for seasoned musicians.
Observations and Trends
Based on observations, it appears that the raised fifth (often enharmonically equivalent to the diatonic third scale degree in minor mode) is more frequently altered. This is likely due to the musical context within which jazz musicians operate, where the raised fifth can provide a richer, more complex sound. In contrast, when a flat ninth is used, it can serve as a resolution or a more dissonant sound, depending on the musical context.
Conclusion
Altered dominant seventh chords are a powerful tool in jazz music, adding a dynamic and rich harmonic palette to compositions and performances. Understanding these chords and their usage is essential for any jazz musician or enthusiast. Whether you are a seasoned performer or a casual listener, the subtle changes in alterations can significantly affect the overall mood and emotional impact of a piece of music.