Harmonic scale
The harmonic scale, also known as the harmonic minor scale, is a seven-note diatonic scale derived from the natural minor scale by raising the seventh scale degree by a semitone, which creates a leading tone that enhances resolution to the tonic and allows for the formation of a major dominant chord in minor keys.[1] This modification results in an interval structure of whole step, half step, whole step, whole step, half step, augmented second (approximately 1.5 steps), and half step, distinguishing it from the natural minor's more even stepwise motion.[2] Widely used in Western classical music since the Baroque era, the harmonic scale provides harmonic tension through its raised seventh, enabling progressions like the authentic cadence (V-i) that resolve more emphatically than in the natural minor.[1] For example, in A harmonic minor (A-B-C-D-E-F-G♯), the G♯ functions as the leading tone to A, supporting chords such as E major (the dominant).[2] It also appears in jazz, metal, and flamenco for its exotic, tense sound, often generating modes like Phrygian dominant when starting from the fifth degree.[3] Unlike the melodic minor scale, which raises both the sixth and seventh degrees for smoother ascending melodies, the harmonic scale prioritizes vertical harmony over linear flow, making it essential for chordal writing in minor tonalities.[1]Definition and Basics
Overview
The harmonic minor scale is a seven-note diatonic scale variant of the natural minor scale, formed by raising the seventh scale degree by one semitone to create a leading tone that strengthens tonal resolution.[4] This adjustment distinguishes it from the natural minor, providing a framework for enhanced harmonic function in Western music theory. Historically, the harmonic minor scale emerged in Western classical music during the Baroque period (approximately 1600–1750), as composers sought to resolve the weaker subtonic-to-tonic pull in the natural minor scale by incorporating a raised seventh for more compelling cadences.[5] This development aligned with the era's shift toward tonal harmony, where the leading tone became essential for defining key centers and driving musical progression.[6] By the early Common Practice period, including Baroque and Classical styles, the raised seventh was a standard feature in minor keys to support dominant-tonic resolutions.[7] In its general structure, the harmonic minor is a heptatonic scale with an interval pattern that produces an augmented second between the sixth and seventh degrees, contributing to its characteristic tension.[8] This configuration serves a primary purpose in creating harmonic stability, particularly by enabling dominant seventh chords to resolve effectively to the tonic, thus facilitating tension and release in compositions.[9]Scale Formula and Intervals
The harmonic minor scale, often referred to as the harmonic scale, is constructed using the following interval pattern from the tonic: whole step (W), half step (H), whole step (W), whole step (W), half step (H), augmented second (W+H), half step (H).[10] This sequence results in the scale degrees 1 (tonic), 2, ♭3, 4, 5, ♭6, and 7 (raised leading tone), where the ♭3 and ♭6 provide the minor character, while the raised 7 creates a strong pull toward the tonic.[11] In terms of semitones, the harmonic scale features three half-step intervals: between degrees 2 and ♭3, 5 and ♭6, and 7 and the octave (8). These half steps total three in the scale, contrasting with the more even distribution in major scales and contributing to its tense, directional quality.[11] The pattern accumulates as follows: 2 semitones (1-2), 1 semitone (2-♭3), 2 semitones (♭3-4), 2 semitones (4-5), 1 semitone (5-♭6), 3 semitones (♭6-7), and 1 semitone (7-8).[12] The defining feature of the harmonic scale is the augmented second—a three-semitone interval—between ♭6 and 7, which imparts a distinctive exotic or tense sound not found in the natural minor scale. This interval arises from the combination of the lowered sixth and raised seventh, creating an asymmetrical step that emphasizes the leading tone's resolution while maintaining the minor mode's overall profile.[10] Acoustically, the raised seventh in the harmonic scale relates to the harmonic series by approximating the major third in the dominant (V) chord, which is derived as the fifth partial overtone of the dominant's fundamental tone. This connection strengthens the V-i resolution, as the major third enhances harmonic stability and tension release in minor keys.[13]Construction and Variants
Comparison to Other Minor Scales
The natural minor scale is identical to the harmonic minor scale in its first six degrees but differs by using a subtonic (♭7) rather than a leading tone (natural 7), which results in a weaker sense of resolution toward the tonic and avoids the augmented second interval present in the harmonic minor.[14] This subtonic creates a minor seventh chord on the dominant (v), contrasting with the major dominant seventh (V7) enabled by the harmonic minor's raised seventh.[15] The melodic minor scale aligns with the harmonic minor in its ascending form by raising both the sixth and seventh degrees, thus matching the leading tone while eliminating the augmented second for smoother stepwise motion; however, it descends using the natural minor pattern, reverting the sixth and seventh to their flattened positions.[16] This bidirectional adjustment makes the melodic minor particularly suited for linear melodic lines in performance, as opposed to the harmonic minor's consistent structure across ascent and descent.[14] Functionally, the harmonic minor prioritizes chordal harmony, such as facilitating the V7-i progression for stronger cadential resolution in polyphonic settings, while the melodic minor emphasizes smoother melodic contour in ascending passages, and the natural minor serves as the foundational diatonic basis without alterations for either purpose.[15][16]| Scale | Ascending Intervals | Descending Intervals |
|---|---|---|
| Natural Minor | W-H-W-W-H-W-W | W-H-W-W-H-W-W |
| Harmonic Minor | W-H-W-W-H-A2-H | W-H-W-W-H-A2-H |
| Melodic Minor | W-H-W-W-W-W-H | W-H-W-W-H-W-W |
Key Signatures and Notation
The harmonic minor scale employs the same key signature as its corresponding natural minor scale, which is derived from the relative major key located a minor third above the tonic. For instance, the key signature for A harmonic minor matches that of C major, featuring no sharps or flats, while the raised seventh degree (G♯) is indicated by an explicit accidental whenever it occurs in the melody or harmony.[10] Similarly, in E harmonic minor, the key signature contains one sharp (F♯), with the raised seventh (D♯) notated as a sharp alteration from the natural D, rather than its enharmonic equivalent E♭, to clearly denote the structural modification.[2] Notation conventions for the harmonic minor scale require the raised seventh to be marked with an accidental in all relevant positions, ensuring the leading tone's presence for harmonic resolution, such as strengthening the dominant chord. Unlike the melodic minor scale, the harmonic minor maintains the same pattern—raised seventh included—both ascending and descending, without alteration. However, in descending melodic passages, composers often revert to the natural minor seventh for smoother contour and to avoid the awkward augmented second interval between the lowered sixth and raised seventh, though the harmonic form remains primary when emphasizing chordal functions like the V-i progression.[18][2] In practical sheet music applications, classical compositions explicitly notate these accidentals to guide performers precisely, as seen in works requiring dominant resolution. In jazz contexts, the harmonic minor scale is frequently implied through chord symbols—such as a V7 chord leading to the tonic minor—rather than fully written out in the melody, allowing improvisers flexibility while prioritizing harmonic intent over scalar notation.[10][3]Musical Applications
Role in Harmony and Chord Progressions
The harmonic minor scale serves as a foundational structure for building diatonic triads in minor keys, providing distinct chord qualities that enhance tonal resolution compared to the natural minor scale. The raised seventh scale degree alters several triads, resulting in the following common set built on each scale degree: i (minor triad), ii° (diminished triad), III+ (augmented triad), iv (minor triad), V (major triad), VI (major triad), and vii° (diminished triad).[19][4] These qualities arise from stacking thirds within the scale, where the leading tone (raised seventh) introduces the major third in the V triad and contributes to the diminished nature of ii° and vii°.[19] A primary role of the harmonic minor scale lies in its support for the dominant function, particularly through the V (major) triad and its seventh-chord extension, V7. The raised seventh acts as a leading tone, creating a strong half-step pull to the tonic, which enables authentic cadences absent in the natural minor's weaker v (minor) triad.[4][7] This V7 chord incorporates the major third (derived from the leading tone) and resolves tensions effectively to the i chord, avoiding the parallel motion issues in natural minor progressions where the subtonic (♭7) leads to parallel fifths or octaves when moving from v to i.[4][20] Common progressions in the harmonic minor leverage these chords for structural coherence, such as i–V–i, which provides a basic tonic-dominant resolution, and i–iv–V–i, incorporating the subdominant for added pre-dominant tension before the dominant.[4] The augmented second interval between the ♭6 and raised 7 creates characteristic tension in the VI (♭VI major) and vii° chords, often heightening dramatic resolution when these progress to i or V.[4] This setup allows the harmonic minor to address the natural minor's resolution weaknesses by prioritizing linear voice leading toward the tonic, fostering a sense of directed harmonic motion.[21]Usage in Genres and Composers
In the Classical era, composers such as Johann Sebastian Bach and Wolfgang Amadeus Mozart frequently employed the harmonic minor scale to facilitate strong cadences in minor-key works, enhancing structural resolution in fugues, sonatas, and chorales. Bach integrated the harmonic minor scale into vocal lines, as seen in the aria "Quia respexit" from his Magnificat, BWV 243, where the raised seventh degree creates a poignant leading tone that underscores the text's emotional intensity.[22] Mozart similarly utilized the scale's augmented second interval for dramatic cadential emphasis in minor-key sonatas, such as the stormy opening of Piano Sonata No. 16 in C Minor, K. 457, where it supports V-i progressions to heighten tension and resolution.[23] During the Romantic period, Richard Wagner and Frédéric Chopin drew on the harmonic minor scale to evoke dramatic tension and emotional depth, particularly in operatic and pianistic expressions of longing. Wagner incorporated elements of the scale in modulatory passages to blur tonal boundaries and build suspense, as in the prelude to Tristan und Isolde, where the raised seventh contributes to prolonged harmonic ambiguity and psychological intensity.[24] Chopin, in his nocturnes, used the harmonic minor to infuse lyrical melodies with a sense of melancholy and inevitability; for instance, in Nocturne in C Minor, Op. 48, No. 1, the scale's characteristic intervals underpin chromatic voice leading that amplifies the piece's introspective mood.[25] Beyond classical and Romantic traditions, the harmonic minor scale and its modes appear prominently in various genres for their evocative qualities. In flamenco music, the Phrygian dominant mode—derived as the fifth mode of the harmonic minor scale—defines the genre's passionate, exotic flavor, as heard in traditional palos like the soleá, where it generates a tense, unresolved sound over dominant harmonies.[26] Heavy metal often leverages the scale for aggressive, otherworldly effects; neoclassical metal guitarist Yngwie Malmsteen employs the Phrygian dominant in "Trilogy Suite Op: 5" to evoke a mystical intensity, while earlier examples like Scorpions' "The Sails of Charon" blend it with Phrygian elements for an epic, shadowy atmosphere.[27] In jazz, the harmonic minor serves as a foundational scale for minor-key improvisation and chord substitutions, providing the raised seventh needed for dominant resolutions in ii-V-i progressions, as analyzed in standard jazz harmonic practices.[28] In modern contexts, the harmonic minor scale influences film scores and 20th-century compositions, often synthesizing with other modes to convey suspense or innovation. Composers like Bernard Herrmann and John Williams use the scale's dissonant augmented second in thriller scores—such as in Psycho or Jaws—to create liminal tension between consonance and dissonance, aligning with non-diatonic progressions in post-2000 media.[29]Modes and Derivatives
Primary Modes
The primary modes of the harmonic scale consist of the seven rotations derived from the harmonic minor scale (formula: 1 2 ♭3 4 5 ♭6 7), each beginning on a successive degree and retaining the characteristic raised seventh of the parent scale in varying positions. These modes, known collectively as the harmonic minor modes, expand the tonal possibilities beyond the parent scale by shifting the placement of the augmented second interval (between ♭6 and 7) across different positions, creating diverse harmonic flavors used in jazz, classical, and ethnic music. While all seven modes are theoretically valid, practical usage often favors those with strong resolving tendencies or exotic colors, such as the Phrygian dominant. The Phrygian dominant, as the fifth mode, stands out for its dramatic tension, featuring a minor second (half step) from the tonic to the ♭2, followed immediately by an augmented second leap to the major third; this structure evokes the flamenco and Middle Eastern influences associated with its alternative name, the Spanish gypsy scale, making it the most widely adopted mode from the harmonic minor family.[30][31] The full interval patterns for the primary modes, relative to their tonic, are presented below:| Mode Number | Name | Interval Pattern |
|---|---|---|
| 1 | Aeolian ♮7 (harmonic minor) | 1, 2, ♭3, 4, 5, ♭6, 7 |
| 2 | Locrian ♮6 | 1, ♭2, 3, 4, ♭5, 6, ♭7 |
| 3 | Ionian #5 | 1, 2, 3, 4, #5, 6, 7 |
| 4 | Dorian #4 | 1, 2, ♭3, #4, 5, 6, ♭7 |
| 5 | Phrygian dominant | 1, ♭2, 3, 4, 5, ♭6, ♭7 |
| 6 | Lydian #2 | 1, #2, 3, #4, 5, 6, 7 |
| 7 | Super Locrian ♭♭7 | 1, ♭2, ♭3, 4, ♭5, ♭6, ♭♭7 |