The second scale degree of a diatonic scale
In music theory, the term "supertonic" refers to the second degree of a diatonic scale, typically represented as "II" in harmonic analysis. Positioned just one step above the tonic, which is the scale's first degree, the supertonic plays a pivotal role in crafting musical tension and preparing harmonic resolutions within a composition. For instance:
- In the C major key, the supertonic note is D.
- In the A minor key, the supertonic note is B.
The supertonic note, being only a step away from the tonic, carries a somewhat unsettled or unresolved quality when heard on its own. Frequently, it yearns for resolution to the tonic, which is regarded as the most stable and central note within a key.
From a harmonic perspective, the supertonic chord is often denoted as "ii" (minor) or "II" (major), and it is built upon the supertonic note. In a major key, the ii chord is typically minor, while in a minor key, the II chord usually takes on a major quality. For instance:
- In C major, the ii chord is D minor (D, F, A).
- In A minor, the II chord is B diminished (B, D, F).
The supertonic chord is frequently employed to create harmonic tension, which can then be resolved by transitioning to the dominant chord (the fifth degree of the scale). Subsequently, the dominant chord resolves to the tonic chord. This series of progressions, known as the "ii-V-I" progression, is a common and gratifying method for achieving musical resolution and closure.
In terms of melody, the supertonic note is an indispensable element in crafting melodies and musical phrases. It can be harnessed to introduce a sense of motion and anticipation within a melody, often leading towards the tonic note or other notes within the scale.