Upper structure
In jazz harmony, an upper structure triad refers to a technique where a major or minor triad—comprising tensions such as 9ths, 11ths, or 13ths—is superimposed over an underlying chord, often a dominant seventh, to form a polychord that enriches the harmonic texture.[1] This voicing approach, notated as a slash chord (e.g., Dmaj/C7), groups chord extensions into a familiar triadic shape above the chord's root, third, and seventh, creating bitonal effects by blending two tonal centers.[1] Upper structures are particularly effective for altered dominant chords, where the triad introduces chromatic tensions like the ♭9, ♯9, ♭5, or ♯11, adding color and resolution potential without requiring complex individual note voicings.[2] Upper structure triads simplify the performance of extended harmonies, allowing musicians to imply sophisticated chord qualities using basic triad shapes.[3] In practice, the left hand typically plays the chord's guide tones (third and seventh) or a tritone interval for dominant voicings, while the right hand executes the upper triad, often positioned a major third or perfect fourth above the bass for optimal voice leading.[2] The versatility of upper structures extends beyond dominants to major, minor, and half-diminished chords, though options are more limited for non-dominant types; for instance, a B♭ major triad over G7 implies a G7(#9), facilitating smooth transitions in ii-V-I progressions common in jazz standards.[4] This technique not only aids pianists and guitarists in creating dense, professional-sounding voicings but also serves improvisers by providing scalar frameworks derived from the triad's notes, such as mixing the triad's parent scale with the underlying chord's alterations.[5] Educational resources emphasize practicing upper structures diatonically within a key to internalize their application, as seen in tunes like "Solar" or "All the Things You Are," where they reharmonize phrases for greater expressiveness.[5] Overall, upper structures exemplify jazz's emphasis on efficient, aurally intuitive harmony, influencing contemporary genres like fusion and Latin jazz.Definition
Core Concept
In jazz harmony, an upper structure triad refers to a voicing technique where a major or minor triad is placed in the upper register of the chord, superimposed over a lower structure consisting of the root or bass note and essential tensions, such as the third and seventh, to imply extended or altered harmonies without voicing every individual extension.[2] This approach leverages the familiarity of simple triads to construct sophisticated sounds, particularly for dominant seventh chords.[6] The primary purpose of upper structure triads is to simplify the execution and conceptualization of complex altered dominant chords, such as those featuring alterations like the sharp ninth, flat ninth, or sharp eleventh, by breaking them down into recognizable triad shapes that pianists and arrangers can easily transpose and apply across keys.[2] This method reduces cognitive load during performance, allowing musicians to focus on the overall harmonic color rather than memorizing numerous note combinations for each extension.[6] Unlike full chord voicings that include all chord tones and extensions explicitly, upper structure triads emphasize the upper triad as a self-contained unit, often paired with a minimal lower structure—typically just the tritone formed by the third and seventh of the dominant chord—to outline the harmony's core function while the triad supplies the extensions.[2] In this basic structure, the lower part provides the foundational tension and resolution drive of the chord, while the upper triad contributes the implied alterations and colors, creating a layered effect that enhances harmonic density without overcrowding the voicing.[6]Components
The components of an upper structure in jazz harmony primarily comprise a lower structure voicing and an upper triad, which together create extended chord colors through strategic dissonance.[7] The lower structure elements typically consist of the root (which may be optional, often supplied by bass), the third, and the seventh of the base chord, frequently reduced to the essential tritone interval formed by the third and seventh for a compact foundation.[8] For instance, in a C7 chord, the lower structure might feature E (the major third) and B♭ (the minor seventh), emphasizing the core tension of the dominant seventh without unnecessary density.[9] The upper triad serves as the key building block above this lower foundation, with major triads commonly employed to imply altered dominant tensions such as the sharp ninth (#9). A representative example is an E♭ major triad (E♭-G-B♭) placed over a C bass or lower structure, where the E♭ functions as the #9, introducing vivid dissonance against the chord's natural tones while the G and B♭ reinforce the fifth and minor seventh.[7] Minor triads, in contrast, provide subtler colorations, such as a F♯ minor triad (F♯-A-C♯) over C7, yielding the sharp eleventh (#11 from F♯), the natural thirteenth (13 from A), and the flat ninth (♭9 from C♯, enharmonically D♭).[8][10] In their interaction, the root of the upper triad directly acts as a chord extension relative to the base harmony, transforming a simple seventh chord into a richly textured altered sound; for example, the E♭ root in the aforementioned E♭ major triad over C explicitly supplies the #9 extension, with the triad's other notes contributing complementary tensions like the perfect fifth and minor seventh.[9] This layering allows the upper structure to imply multiple extensions simultaneously without overcrowding the voicing. Voice leading considerations are crucial for effective implementation, as the notes of the upper triad must be positioned to avoid direct clashes with the lower structure's guide tones while deliberately generating productive tensions, such as the half-step dissonance between the #9 (E♭) and the major third (E) in the C7 example, which heightens the dominant's pull toward resolution.[7] Proper spacing—often with the upper triad in the right hand an octave or more above the lower—ensures clarity and smooth progression to subsequent chords.[8]Theoretical Foundations
Relation to Extensions
Upper structure triads relate to chord extensions by superimposing a triad above the root or core tones of a base chord, where the triad's notes function as specific tensions or extensions relative to that base. The root of the upper triad often serves as a ♯9 or ♭9, its third as the 5th or ♯11, and its fifth as the ♭7 or 13th, creating implied polychords that enrich the harmony without explicitly voicing all extensions.[11][6] This approach is particularly prevalent with altered dominant chords, such as V7 types, where upper structures introduce colorful tensions like ♯9 or ♭13. For instance, over a G7 altered chord, a B♭ major triad (♭III relative to G) maps to ♯9 (B♭ as A♯), 5th (D), and ♭7 (F), emphasizing the ♯9 alteration while implying the dominant function. Similarly, an E♭ major triad (♭VI relative to G) provides ♭13 (E♭), root (G), and ♯9 (B♭), adding a tense ♭13 color commonly used in jazz progressions to heighten resolution toward the tonic. These mappings allow pianists to voice complex altered dominants efficiently using simple triads.[11][6] For non-altered chords like major 7ths, upper structures employ minor triads to imply natural extensions such as the 9th, 11th, and 13th, avoiding the dissonant ♯11 associated with Lydian voicings. Over a C major 7th chord, for example, a D minor triad functions as 9th (D), 11th (F), and 13th (A), creating a lush, extended sound that aligns with Ionian harmony without introducing avoid notes. This technique extends to other chord qualities, providing a streamlined way to incorporate upper extensions. Upper structure triads ideally emphasize extensions (9, 11, 13, alterations) while the base voicing handles core tones, though some triads may include core tones enharmonically.[11][12] Theoretically, upper structures offer an advantage by enabling implicit harmony, where the listener's ear perceives the full extensions based on contextual resolution, even though only the triad and bass are voiced explicitly. This reduces the physical hand span required for pianists, facilitating complex voicings in performance while maintaining harmonic clarity and color.[11][13]Scale-Based Derivations
Upper structures in jazz harmony are derived by selecting triads whose notes correspond to scale degrees within the parent scale of the base chord, ensuring all tones fit harmonically while prioritizing extensions and alterations over root, third, fifth, or seventh chord tones to create tension and color. This process maintains coherence by embedding the upper triad directly into the scalar framework associated with the chord, allowing for systematic construction of complex voicings without introducing foreign notes. A prominent example involves the octatonic scale, an eight-note symmetric scale alternating half and whole steps, often applied to altered dominant chords. For a C13♭9♯11 chord, the parent C octatonic scale consists of the notes C-D♭-D♯-E-F♯-G-A-B♭, which encompasses the chord tones (C, E, G, B♭) along with key tensions (D♭ as ♭9, F♯ as ♯11, A as 13th). The upper structure F♯ minor triad (F♯-A-C♯) is selected because each note aligns with scale degrees: F♯ (♯11), A (13th), and C♯ (equivalent to D♭, ♭9), thus providing these specific tensions while omitting redundant chord tones.[10] The whole-tone scale, a six-note symmetric scale built entirely of whole steps, is used for dominant chords emphasizing augmented or #5 qualities. An upper structure like the A augmented triad (A-C♯-F) over a B7 chord derives from the B whole-tone scale (B-C♯-D♯-F-G-A), where A (♭7), C♯ (9th), and F (#11) introduce these tensions symmetrically within the scale's framework.[14] Other scales yield additional derivations suited to specific harmonic roles. The diminished scale (another name for the octatonic), with its alternating whole-half steps, supports symmetric voicings for dominant 7th chords, where upper triads like minor or diminished types are chosen from scale degrees to emphasize b9, #9, and #11 alterations, creating balanced, repeating patterns across tritone-related chords.[15] For basic dominant chords, the Mixolydian mode serves as the parent scale, such as C Mixolydian (C-D-E-F-G-A-B♭) for C7, where relative minor triads (e.g., D minor: D-F-A) add 9th (D), 11th (F), and 13th (A) via scale degrees 9, 11, and 13, enhancing the chord without heavy alteration.[6]Historical Development
Origins in Jazz
The technique of upper structures in jazz emerged during the bebop era of the 1940s, where pianists such as Bud Powell and Thelonious Monk incorporated triad-based voicings into their complex chord solos to handle rapid harmonic changes efficiently. Powell's shell voicings, often consisting of root, third, and seventh, laid foundational groundwork for layering triads to imply extended harmonies without full chord stacks, allowing for agile left-hand comping during fast tempos. Similarly, Monk employed pure triads and dissonant intervals in his voicings, creating tension through semitones at the chord's base while using triads on top to outline harmonic motion in solos like his 1957 rendition of "I Should Care." These approaches prioritized harmonic density and rhythmic drive over traditional block chords, marking an early shift toward superimposing simpler structures for improvisational freedom.[16][17][18] In the 1950s cool jazz transition, particularly on the West Coast and in Miles Davis's quintet, these ideas were refined into more impressionistic applications, with Bill Evans popularizing upper triads for added color in rootless voicings. Evans's style emphasized the upper partials of chords—often major or minor triads placed above bass notes or guide tones—to evoke modal ambiguity and subtle tension, as heard in his comping on tracks from the album Kind of Blue (1959). This marked a departure from bebop's denser textures toward sparser, more evocative harmonies that highlighted intervallic relationships over complete seventh chords.[19][20] The big band era also influenced upper structure techniques through arrangements like those of Gil Evans, who layered triads in orchestral settings to build polychordal effects, such as superimposing a D major triad over a G-D fifth for bi-tonal subtlety in works from the late 1940s and 1950s. These layered approaches in larger ensembles inspired adaptations for small-group piano, bridging orchestral color to intimate jazz combos. By the 1960s, upper structures were increasingly employed in modal jazz, coinciding with its rise, where reduced reliance on full seventh chords favored triad overlays for harmonic simplification and improvisational space, as in Miles Davis's modal explorations.[21][22]Key Influences and Evolution
In the 1960s, upper structures gained prominence in modal jazz through the innovative voicings of pianists Herbie Hancock and McCoy Tyner. Hancock employed upper triads to blend quartal harmonies, as evident in his composition "Maiden Voyage," where suspended chords incorporate triad-based upper extensions to evoke ethereal, static modal atmospheres.[23][24] Similarly, Tyner integrated upper-structure triads over modal progressions, superimposing them to add tension and color, particularly in his work with John Coltrane, enhancing the genre's shift toward expansive, non-functional harmony.[25][26] By the late 1970s, Chick Corea further abstracted upper structures in jazz fusion, using them to create polychordal textures that bridged acoustic and electric idioms, as seen in his Return to Forever recordings where triads overlay complex dominant and modal foundations.[27] Theoretical codification of upper structures as a pedagogical tool emerged in the late 1980s, with Mark Levine's "The Jazz Piano Book" (1989) dedicating a full chapter to their application, emphasizing triads over tritones for altered dominants and providing systematic exercises for jazz pianists. Concurrently, Berklee College of Music integrated upper structures into its harmony curriculum, developing methods like upper-structure triads derived from chord scales to train students in contemporary comping and reharmonization.[28][29] The technique evolved into fusion and modern jazz during the 1970s and 1980s, expanding beyond jazz into broader arrangements, such as Pat Metheny's use of upper triads in guitar-piano collaborations to generate lush, impressionistic harmonies.[30] The advent of digital tools like MIDI in the 1980s further reinforced triad-based composition, enabling precise layering of upper structures in sequencing and production for improvisational and ensemble settings.[5] Globally, upper structures spread to Latin jazz through Corea's fusions, where they enriched rhythmic montunos and chordal vamps, and adapted to contemporary improvisation across genres, evolving from dominant-focused applications to versatile extensions over all chord types for enhanced expressive depth.[31][27]Examples
Dominant Chord Voicings
Upper structure voicings for dominant 7th chords typically involve a lower structure consisting of the chord's 3rd and ♭7th, forming a tritone, with a major triad placed above it to imply specific extensions and alterations.[2][32] A classic example is the C7♯9 voicing, where the lower structure uses E (3rd) and B♭ (♭7th), and the upper structure is an E♭ major triad (E♭-G-B♭). This configuration implies the ♯9 (E♭), 5th (G), and ♭7 (B♭), creating a tense, bluesy sound characteristic of jazz and blues contexts, often evoking an edgy tension suitable for dominant resolutions.[32][11] Another common voicing appears in the B7(9, ♯11, 13), employing a lower structure of D♯ (3rd) and A (♭7th), overlaid with a D♭ major triad (D♭-F-A♭). Here, the upper triad suggests the 9th (D♭), ♯11 (F), and 13th (A♭), adding dissonant color and forward momentum to the dominant function.[2][32] Effective voicing tips include positioning the lower tritone in the bass register for stability while placing the upper triad higher up to emphasize the extensions, and inverting the triad—such as G-B♭-E♭ for the C7♯9 example—to facilitate smoother voice leading between chords.[2][9] Common patterns for these voicings derive from specific scale degrees: a ♭III major triad produces the ♯9 tension over the dominant, as in the C7♯9 case, while a III major triad yields the 9/♯11/13 alterations, aligning with the implications in the B7 example.[32][11]Extended Harmony Examples
Upper structures for extended harmonies allow musicians to incorporate multiple tensions such as 9ths, 11ths, 13ths, and alterations into major seventh, minor seventh, and complex dominant chords, creating richer, more colorful voicings than basic triad or seventh constructions. By superimposing a triad over a rootless lower structure—typically the third and seventh of the chord—these voicings imply polychordal effects while maintaining harmonic function, often drawing from modal or symmetric scales for derivation. This approach is particularly effective in jazz improvisation and composition, where it facilitates smooth voice leading and tension resolution.[32] A prominent example appears in the C13♭9♯11 chord, an extended altered dominant. The lower structure comprises E and B♭, the major third and flat seventh relative to the root C. Over this, an F♯ minor triad (F♯–A–C♯) serves as the upper structure, implying the ♯11 (F♯), 13th (A), and ♭9 (C♯). This voicing derives from the half-whole octatonic scale (C–D♭–E♭–E–F♯–G–A–B♭), which supplies the necessary altered tones for tension before resolving to F major.[33] For CMaj7, a rootless voicing variant uses E–B as the lower structure, the major third and seventh. The upper structure is a D minor triad (D–F–A), which adds the 9th (D), 11th (F), and 13th (A), evoking the Ionian mode's extended colors without including the root, thus promoting a lighter, airy texture suitable for ballads or standards.[34] In minor seventh chords such as Dm7, the lower structure F–C provides the minor third and flat seventh. Pairing this with an F major triad upper structure (F–A–C) reinforces core chord tones—the 3rd (F), 5th (A), and 7th (C)—while imparting modal color through its major quality, often used in Dorian contexts for subtle warmth and implied extensions.[35] To highlight specific tensions like the 13th, performers vary the upper triad's inversion, such as employing second inversion (e.g., A–D–F♯ for an F♯ minor triad), which positions the triad's fifth at the base of the upper voicing. This arrangement allows higher extensions to resonate prominently on top, enhancing clarity and melodic potential in dense harmonic settings.[36] Pianist Herbie Hancock notably utilized these extended upper structures in his modal jazz works to layer harmonic complexity.[23]Applications
Piano and Keyboard Techniques
In piano and keyboard performance, the left hand provides the foundational lower structure of an upper structure triad by playing the third and seventh of the dominant chord, forming a tritone interval that defines the chord's essential tension. This voicing is often doubled in octaves to enhance bass clarity and projection, particularly in solo or combo settings.[2][9] Including the root below the tritone can add stability when needed, but the sparse two- or three-note configuration in the left hand is preferred to avoid muddiness from overcrowding the low register with additional chord tones.[17] The right hand then voices the upper triad in close position, typically placed one to two octaves above the left hand to maintain separation and allow the extensions to ring clearly. This positioning creates a layered polychord effect, where the triad's notes imply the dominant chord's alterations such as the ♯9 or ♯5. The sustain pedal should be used sparingly—often in half-pedaling—to preserve the dissonant tensions without blurring the precise intervallic relationships between hands.[37][38] For improvisation, the upper triad functions as a guide tone set, offering a concise framework of chord tones and tensions from which melodic lines can be constructed, enabling fluid navigation over dominant resolutions. Arpeggiating the triad in the right hand introduces rhythmic variety and forward momentum, particularly effective in standards like "All the Things You Are," where such voicings enhance the harmonic flow during ii-V-I sequences. For example, a C7♯9 voicing employs an E♭ major triad as the upper structure to imply its characteristic alterations.[39][38][5] Practice techniques emphasize cycling through ii-V-I progressions in all keys, substituting upper triads specifically over the V7 chord to develop voicing fluency and hand independence. Exercises begin at moderate tempos, focusing on clean transitions between the lower tritone and upper triad, gradually incorporating inversions and rhythmic displacements to simulate real-time performance demands.[33][32]Arrangement and Orchestration
In big band jazz arrangements, upper structure triads are frequently assigned to the horn sections, particularly the trumpets, positioned over a tritone or altered dominant in the rhythm section to generate sectional tension and subsequent release. This technique creates polychordal textures that enhance harmonic complexity while maintaining clarity in ensemble playing. For instance, in Thad Jones' "Cherry Juice," a G major triad is voiced in the trumpets over an F9#11 chord provided by the rhythm section, blending octatonic and Mixolydian collections to build dissonance through extensions like #9 and b13, which resolve efficiently via voice leading to consonant triads. Similarly, in "Three and One," Jones employs a Bb-D-F triad over D+7#9 in the brass, with the lead trumpet articulating melodic centricity amid chromatic planing, allowing the horns to contrast scalar motion for dynamic release. These voicings, often extended to six or more pitch classes, underscore Jones' influence in mid-20th-century jazz orchestration by prioritizing smooth resolutions over base chord tones. In small jazz ensembles such as quartets, upper structures facilitate layered harmony by dividing responsibilities: the guitar and bass manage the lower chord foundation, including roots and guide tones, while the piano or saxophone delivers the upper triad for comping, promoting rhythmic interplay and avoiding sonic clutter. This approach enriches comping patterns, enabling the pianist to imply extensions like 9ths and 13ths through triad superimposition on dominant chords, as outlined in Berklee's methods for contemporary jazz harmony. For example, over a C7 chord, a piano might voice an Eb major triad (implying #9, 5th, and b7) above the tritone (E-Bb), supporting saxophone lines in standards like "Solar" and fostering smooth voice leading during ensemble comping. Such distribution heightens the quartet's harmonic depth, drawing from modern jazz practices where upper structures prioritize melodic support over dense block chords. Beyond traditional jazz, upper structures extend to non-jazz contexts for infusing sophisticated tension. In film scoring, they add a jazz-inflected flavor to orchestral underscores, employing polychords to evoke mood without overwhelming narrative cues, as evidenced in analyses of composers blending jazz harmony with cinematic orchestration. In modern pop and R&B, particularly neo-soul productions by artists like D'Angelo, subtle upper structure triads provide extended harmony beneath vocals, creating off-balance yet resonant progressions that update soul traditions with jazz-derived dissonance. Orchestral adaptations of upper structures leverage sectional timbres for dramatic effect, with strings handling upper triad swells for sustained resonance and brass delivering lower-structure punch for rhythmic drive, preserving simplicity in hybrid genres like jazz fusion. A seminal example appears in Gil Evans' "Saeta" from Sketches of Spain, where a D major upper structure triad layers over a G-D perfect fifth drone in the bass and brass, incorporating orchestral winds and trumpet for bitonal tension that resolves through subtle clashing intervals like F# against G Aeolian. This orchestration, blending folk influences with jazz polychords, exemplifies how upper structures adapt to larger ensembles by emphasizing textural contrast over harmonic density, influencing later fusion evolutions.Notation
Shorthand Symbols
In jazz notation, upper structure triads are often abbreviated using "US" followed by a Roman numeral that denotes the scale degree of the triad's root relative to the underlying chord's root.[40] This concise system facilitates rapid interpretation during performance, particularly for dominant seventh chords where the upper triad supplies tensions such as the 9th, #11th, or 13th.[2] For instance, the symbol "C7 US♭III" specifies an E♭ major triad over a C7 chord, implying the notes E♭-G-B♭ above the C7's foundational tones.[41] Variations of this shorthand include "UST" to explicitly indicate an upper structure triad, with the triad's quality appended for clarity, such as "US♭III maj" for a major triad or "US♯II min" for a minor triad.[33] These extensions ensure precision when the default major quality does not apply, as minor upper structures are common for altered dominants or modal interchanges.[10] The Roman numeral always reflects the interval from the chord root, allowing transposition across keys without rewriting the full chord symbol.[27] This notation is common in jazz educational materials and teaching resources, where it facilitates understanding of complex harmonies.[42] It promotes quick voicing decisions, as seen in "Dm7 US I maj," which directs a major triad on the chord's root (D major over Dm7) to evoke a brighter, extended sound.[43] By focusing on the upper triad, the system streamlines communication among ensemble members, especially pianists and guitarists handling chordal responsibilities.[44] However, the shorthand presumes familiarity with the lower structure, typically the chord's third and seventh forming a tritone (e.g., E-B♭ under the upper triad for C7), which must be voiced separately for harmonic completeness.[9] Outside professional jazz contexts, such as classical or pop arrangements, this notation lacks universality and may require full chord specifications or slash notation instead.[11]Visual and Standard Representations
In staff notation, upper structures are visually depicted by separating the lower structure—typically the 3rd and flat 7th of the dominant chord—in the bass clef, often spaced for clarity, from the upper triad placed in close voicing within the treble clef. For instance, a C7#9 chord might show E and B♭ in the bass clef (spaced an octave apart if needed), while the E♭ major triad (E♭-G-B♭) appears in the treble clef above, employing ledger lines to accommodate wider intervals between the structures. This layered approach highlights the polychordal nature without cluttering the score, allowing performers to interpret the extensions implied by the triad's placement.[2][37][45] Chord diagrams for piano often illustrate the left hand playing the tritone interval (e.g., E-B♭ for C7), positioned low on the keyboard diagram, with the right hand triad (e.g., E♭-G-B♭) shown in higher registers to emphasize the split voicing. On guitar, adaptations of these voicings use partial barre techniques to isolate the upper triad notes across higher frets, such as barring the 3rd fret for an E♭ major triad while incorporating the lower tritone via open or low-position strings, enabling compact realizations of extended harmonies.[37][46] In music notation software like Sibelius and Finale, upper structures are entered as layered notes across staves or via custom chord symbols such as "C7 (E♭Δ)," where Δ signifies a major triad, facilitating quick input and playback that layers the sounds distinctly in audio exports. These tools support visual aids like playback highlighting to demonstrate the equivalence between the upper structure and full extended voicings.[47][48] Comparative visuals in educational materials often present side-by-side diagrams: a full extended chord like C7#9 (with notes C-E-G♭-B♭-E♭) in one column versus its upper structure equivalent (E-B♭ below, E♭-G-B♭ above) in another, underscoring their sonic identity while simplifying notation for practical use. The following table illustrates this for select dominant chords:| Chord | Full Extended Voicing | Upper Structure (LH / RH) | Equivalent Sound |
|---|---|---|---|
| C7#9 | C-E-G♭-B♭-E♭ | E-B♭ / E♭-G-B♭ (E♭Δ) | C7#9 (US♭III) |
| G7♭9♯11 | G-B-D♭-F-A♭-C♯ | B-F / D♭-F-A♭ (D♭Δ) | G7♭9♯11 (US♯IV) |