Dominant seventh chord

Definition

A dominant seventh chord is a four-note chord formed by stacking a major triad with a minor seventh above the root. It plays a crucial role in tonal music as it typically leads to the tonic, creating tension that resolves in harmonic progressions. The dominant seventh chord's distinctive sound is essential for establishing a strong sense of key and movement within a piece.

5 Must Know Facts For Your Next Test

1. A dominant seventh chord consists of four notes: the root, major third, perfect fifth, and minor seventh.
2. In the key of C major, the dominant seventh chord is G7, which includes the notes G, B, D, and F.
3. The dominant seventh chord creates strong tension that typically resolves to the tonic chord, leading to a sense of completion in musical phrases.
4. This chord can be altered by adding or modifying notes, such as altering the fifth or raising/lowering the ninth for different harmonic effects.
5. In jazz and contemporary music, dominant seventh chords are often used with extensions, such as ninths and thirteenths, to create richer harmonic textures.

Review Questions

• How does a dominant seventh chord function in relation to its resolution to the tonic?
  • The dominant seventh chord creates harmonic tension that naturally resolves to the tonic. This occurs because the tritone interval within the dominant seventh (the minor seventh and major third) strongly pulls towards the tonic note, creating a need for resolution. For example, in the key of C major, G7 resolves to C major, providing a satisfying closure and reinforcing the sense of key.
• Discuss how alterations to a dominant seventh chord can affect its function within a harmonic progression.
  • Altering notes within a dominant seventh chord can change its function and emotional impact within a progression. For instance, raising the fifth or adding extensions like the ninth can create additional tension or color. In jazz contexts, using a G7#5 instead of G7 introduces unique dissonance that demands different resolutions or leads to unexpected harmonic paths, showcasing versatility in composition.
• Evaluate the role of dominant seventh chords in establishing key relationships and their use in modulations.
  • Dominant seventh chords are critical in establishing and maintaining key relationships due to their inherent tendency to resolve to tonic chords. In modulations, they can facilitate shifts from one key to another by acting as secondary dominants. For instance, using D7 as a dominant seventh can lead effectively into G major, creating a seamless transition between keys and enriching harmonic texture. This ability to pivot between keys makes them essential tools for composers looking to create dynamic musical narratives.

Related terms

Tonic: The tonic is the first scale degree of a musical scale, serving as the home note or central pitch around which the other notes are organized.

Subdominant: The subdominant is the fourth scale degree in a key, often functioning as a preparatory chord that leads to the dominant chord.

Diatonic: Diatonic refers to the notes that belong to a specific scale or key, excluding any accidentals that may alter the pitches.