Visual and Performing Arts, Part 22
Question 1: Describe and discuss chord extensions.
Answer 1: A chord can be extended by adding notes to increase the texture and dissonance and adhering to the same structure already established within the chord. The additional notes added to enrich the existing chord are referred to as extensions, tensions, or upper structures. The resulting sound is the extended chord, though this construction is also called polychord, polytonal chord, or polymodal chord. When extending the seventh chord, for example, the same pattern of the stacking of thirds should be applied. If the chord tone is raised or lowered, the quality is also subsequently raised or lowered. Alternation of extensions should not change the quality of the chord. Consider the following: Cmaj9 (C E G B D) to Cmaj9#11 (C E G B D F#) to cmaj13#11 (C E G B D F# A). Dissonance can be created without any context; a diminished seventh chord can be dissonant without any extensions.
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Question 2: Define upper structure.
Answer 2: Upper structures usually refer to triads played in the upper register . They have a different root than the triads played in the lower register where the upper structure is often a major or minor triad. This extended chord is referred to as the polychord and is very common over the dominant seventh chords. Polychords can, however, compliment other chordal structures. With the top 3 notes as B E G# in the E major triad, the G# acts as the diminished ninth and E is the thirteenth of the G7 chord. The specific notes maintain their own harmonic function within the G7 but are heard as 1 sound, which is really 2 keys at the same time. This combined sound of E and G major is polytonality. This format is often shown as one key over another, such as E7.
Question 3: Describe and discuss hybrid chords.
Answer 3: Hybrid chords are also known as splash chords and are usually written as C/B so that C is the chord and B is the bass note. The structure of the splash chord demarcation is different from the polychord, since the polychord is written as chord on top of chord with a line separating the two, and the hybrid chord is written side-by-side with a slash mark. The polychord refers to one combined sound, whereas the hybrid chord just indicates which note is the bass. With a bass note G, the splash cord Fmaj7/G has the chord Fmaj7 and sounds like the G13sus4. The resulting sound will add consonance or dissonance based on the surrounding notes and context of the music.
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