Locrian mode: music examples and harmonic structure

Music theory describes seven diatonic scales of which the major and minor scales are the most functional and therefore have dominated both classical and popular music for centuries. Five more scales, named after the regions of ancient Greece, form so-called modal modes sometimes used by composers to tie a piece of music to a specific area in order to invoke an emotional connection to the region and its culture.

A modal mode can be either major or minor depending on the construction of the tonic triad which is built on the first scale degree. Following this logic, the Lydian and Mixolydian are major modes, the Phrygian and Dorian are minor modes, while the Locrian is neither major nor minor based on the fact that its tonic chord is diminished.

Diverting from the natural minor scale, the Locrian scale sees two changes in the second and fifth scale degrees which are lowered by a semitone. The altered fifth scale degree creates the sensation of dissonance also called the tritone in a tonic triad.

C Locrian scale:

Among the triads built on each scale degree of the Locrian mode, there are three major chords rooted in the second, fifth, and sixth degrees, as well as three minor chords rooted in the third, fourth, and seventh degrees. For example, C Locrian mode contains the following triads (denoted with Roman numerals and chord symbols): i^o–Cdim, II–D♭, iii–E♭m, iv–Fm, V–G♭, VI–A♭, vii–B♭m.

The Roman numeral analysis of C Locrian mode:

In tonal music, the creation of tension and its resolution occurs when the harmonic functions of the tonic, subdominant, and dominant are combines, embodying all seven chords of the diatonic mode. The tonic chord is the most important element of musical harmony due to its establishing role in the opening and closing points of almost any work.

When used in the first bars of a piece, the tonic chord establishes the tonal center, while the following chords bring instability to the created structure and therefore raise a sense of expectation towards the return to the established tonic triad. A return to the tonic by way of resolution of instability tends to alleviate the newly accumulated tension and bring a sense of relief. Naturally, a diminished tonic chord containing a dissonance cannot provide a stable tonic function which makes the Locrian mode mostly theoretical.

In classical music, it is difficult to find a work entirely written in the Locrian mode although its elements appear in works of the 20th-century composers who, for the most part, represented avant-garde and modernist movements. Such an example featuring some Locrian aspects can be found in Prelude in B Minor by Sergei Rachmaninoff. Here, the composer intermittently lowers the second and fifth scale degrees of the natural minor mode.

Listen to Rachmaninoff's Prelude in B Minor performed by Sviatoslav Richter:

An impressive attempt to create a song in the Locrian mode was made by the English musician John Kirkpatrick. His song Dust to Dust develops exclusively in the B Locrian scale, except here this rare diatonic mode is presented only melodically expressed through the vocal line. Instead of a chord sequence, the concertina accompaniment either shows octave doubling of the vocals or simply imitates the vocal line in the absence of any vertical elements of harmony. Due to the lack of essential cadences with the tonic chord, it may be difficult to recognize the beginning and end of stanzas as well as individual lines of the song lyrics.

Listen to Dust to Dust by John Kirkpatrick:

The Locrian mode is not only limited to the Western theory canon—its analogs can be found in global musical traditions such as classical music of the Middle East where the Maqam Lami scale is the equivalent of the Locrian scale. However, in Turkish and Arabic traditional music there are no vertical elements of harmony (or, in other words, chords) which relegates the use of the Locrian mode to melodic forms.