Submediant
In music theory, the submediant is the sixth scale degree of a diatonic scale, positioned midway between the upper tonic and the subdominant, and it also denotes the triad built on that degree.[1][2] In a major key, the submediant chord is a minor triad (Roman numeral vi), comprising the sixth, root (tonic), and third scale degrees, such as A-C-E in C major, which functions as the tonic chord of the relative minor key.[3][4] Conversely, in a minor key, the submediant chord is a major triad (Roman numeral VI), serving as the subdominant of the relative major key, for example, F-A-C in A minor.[3][4] The submediant chord typically acts as a weak predominant in harmonic progressions, often bridging the tonic to stronger pre-dominants like IV or ii, thereby building subtle tension toward the dominant.[4] It frequently appears in deceptive cadences, where the expected resolution from V to I instead lands on vi, creating an element of surprise and emotional depth, as heard in countless classical and popular compositions.[4][5] Additionally, the submediant can prolong the tonic function when substituting for I, due to their shared scale degrees, or facilitate smooth modulations to relative keys, enhancing tonal variety without abrupt shifts.[4][6] In analysis, its Roman numeral notation—lowercase vi for major keys and uppercase VI for minor—distinguishes its quality and underscores its relational role in diatonic harmony.[3]Definition and Scale Position
Scale Degree
The submediant is the sixth scale degree in the diatonic scale, positioned between the dominant (fifth degree) and the leading tone (seventh degree).[2] In the key of C major, with no sharps or flats in its key signature, the submediant is A natural, forming the ascending scale as C–D–E–F–G–A–B–C.[7] This degree creates a major sixth interval above the tonic or, equivalently, a major third below the tonic's octave displacement.[7] It also lies a minor third above the subdominant (fourth degree); for instance, in C major, the subdominant F ascends a minor third to the submediant A.[2] In solfège notation, the submediant is sung as la in major keys.[8] In natural minor keys, it is le, reflecting the lowered sixth degree relative to the parallel major; for example, in A minor (sharing C major's key signature of no sharps or flats), the ascending scale is A–B–C–D–E–F–G–A, with F as the submediant (le).[9] The submediant thus contrasts positionally with the mediant, the third scale degree located a minor third above the tonic.[7]Relation to Other Degrees
The submediant, as the sixth scale degree, occupies a central position in the diatonic scale, situated halfway between the subdominant (degree 4) and the upper tonic (degree 8) when considering the linear arrangement of the scale extending to the upper octave. This intermediary placement justifies its nomenclature, positioning it equidistant in terms of scale steps from the subdominant below and the upper tonic above, thus bridging the lower and upper halves of the octave.[1][10] In relation to other degrees, the submediant mirrors the mediant (degree 3) through scale symmetry: just as the mediant lies a major third above the tonic, the submediant lies a major third below the upper tonic, creating a balanced reflection around the octave's central axis. This symmetry highlights the submediant's role in the overall proportional structure of the diatonic scale. Compared to the supertonic (degree 2), which serves as the immediate upper neighbor to the tonic, the submediant functions analogously as an upper neighbor within the upper tetrachord, adjacent above the dominant (degree 5). Similarly, while the leading tone (degree 7) provides an upper approach to the tonic from below in the upper tetrachord, the submediant offers a parallel relational approach in its proximity to surrounding degrees, emphasizing stepwise connections in scalar motion.[6][11] To illustrate these relationships, consider a basic diatonic scale diagram in C major, where the submediant (A) acts as a pivot between the lower tetrachord (C-D-E-F) and the upper tetrachord (G-A-B-C):| Degree | Note | Name | Relation to Submediant |
|---|---|---|---|
| 1 | C | Tonic | Five steps below |
| 2 | D | Supertonic | Four steps below |
| 3 | E | Mediant | Mirrors submediant symmetrically |
| 4 | F | Subdominant | Two steps below |
| 5 | G | Dominant | Stepwise lower neighbor |
| 6 | A | Submediant | Central pivot |
| 7 | B | Leading Tone | Stepwise upper neighbor |
| 8 | C | Upper Tonic | Two steps above |
Chord Construction
Triad Formation
The submediant triad is constructed by stacking thirds starting from the sixth scale degree of the diatonic scale, with the root on degree 6, the third on degree 1 (an octave above the root), and the fifth on degree 3.[13] This forms a basic three-note chord in root position.[13] In major keys, the submediant triad is a minor triad due to the minor third interval between the root (degree 6) and the third (degree 1). For example, in C major, the scale degrees yield the notes A (root), C (third), and E (fifth), creating the A minor triad.[13] It is denoted in Roman numeral analysis as vi (lowercase indicating minor quality).[13] In minor keys, the submediant triad is a major triad, typically built using the natural minor scale, where the interval from root (degree 6) to third (degree 1) is a major third. For example, in A minor, the notes are F (root), A (third), and C (fifth), forming the F major triad.[4] It is denoted as VI (uppercase indicating major quality).[4] A basic close-position voicing places the root in the bass, with the third and fifth immediately above it in the closest possible stacking. In C major (vi: A-C-E), this appears as:On a keyboard, this might correspond to A3, C4, and E4 for a compact voicing within one octave.[13] In A minor (VI: F-A-C), the close voicing is F3, A3, and C4.[4]Bass: A (root) Middle: C (third) Treble: E (fifth)Bass: A (root) Middle: C (third) Treble: E (fifth)
Seventh Chords
The submediant seventh chord extends the submediant triad by adding a note a seventh above the root, using the diatonic scale degrees. In major keys, this produces the vi7 chord, built on the sixth scale degree with a minor triad plus a minor seventh, resulting in the intervals of a minor third, perfect fifth, and minor seventh from the root. For instance, in C major, the vi7 chord comprises the notes A–C–E–G, forming a minor seventh chord quality.[14][15] In minor keys, the submediant seventh chord is notated as VI7 and features a major triad with a major seventh (scale degrees 6, 1, 3, 5), yielding a major seventh chord quality. In A minor (natural minor), for example, VI7 consists of F–A–C–E.[16] Common voicings for the submediant seventh emphasize smooth voice leading and balance. In root position for vi7 in C major, a close voicing might stack as A (bass)–C–E–G, providing a compact minor seventh sonority. The first inversion, denoted vi6/5, places the third (C) in the bass, often voiced as C–E–G–A to facilitate connections in progressions; a sample spacing could feature A over C bass in an open voicing for added resonance, such as C (bass)–E–G–A. Second inversion (vi4/3) uses the fifth (E) in the bass, like E–G–A–C, while third inversion (vi4/2) has the seventh (G) in the bass, as in G–A–C–E. Similar inversion principles apply to VI7, with root-position F–A–C–E in A minor, and first inversion VI6/5 voiced as A–C–E–F.[14][15] The vi7 in major keys differs from other diatonic seventh chords, such as the ii7, which shares the half-diminished quality misconception but actually features a diminished fifth; for example, ii7 in C major is D–F–A–C (minor third, diminished fifth, minor seventh), contrasting the vi7's perfect fifth that lends a more stable, less tense character.[14][15]Harmonic Function
In Major Keys
In major keys, the submediant chord, roman numeral vi, functions as a weak pre-dominant, typically extending the tonic area or transitioning to stronger pre-dominants like IV or ii by sharing scale degrees that facilitate smooth voice leading.[4] This role arises from its minor quality, which contrasts with the surrounding major harmonies while avoiding strong resolution tendencies.[4] The vi chord commonly resolves to IV or ii, forming descending-third sequences such as I–vi–IV–ii, or it may lead indirectly to V through these intermediaries; direct motion from vi to V is possible but requires careful contrary motion to avoid parallel fifths.[4] In deceptive cadences, vi substitutes for the tonic after V, evading the expected authentic resolution (V–I) and surprising the listener through common tones like the tonic and third scale degrees.[17][4] As the tonic chord of the relative minor key, vi embodies a modal shift within the same key signature; for example, in C major, the vi chord (A–C–E) serves as the i chord in A minor, enabling subtle tonal ambiguity without introducing accidentals.[18] Representative progressions highlight vi's versatility, such as the canonical I–vi–IV–V cycle, which circulates through tonic, submediant, subdominant, and dominant functions to create cyclical harmonic drive, as in countless hymns and popular songs (e.g., in C major: C–Am–F–G).[19] Another example is the descending-fifths chain vi–ii–V–I, where vi initiates pre-dominant motion toward resolution, often doubled on the root for stability.[4]| Key | Progression | Roman Numerals | Notes |
|---|---|---|---|
| C major | C – Am – F – G | I – vi – IV – V | Balances stability (I, IV) with tension (vi, V); vi adds plaintive color. |
| G major | G – Em – C – D | I – vi – IV – V | vi (Em) prolongs tonic before subdominant arrival. |