A Survey of Music Theory for the College Classroom: Chromatic Harmony 2 and 20th Century Music

Scales in the 20th Century

Overview

One of the fundamental changes that occurred in music beginning in the 19th century was the use of scales outside of the major and minor scales upon which music had been based since the beginning of the Baroque period. Some of these scales were harvested from folk music, others from the Medieval and Renaissance periods, and some were simply created anew. The American composer and pedagogue Mary Jeanne van Appledorn strongly emphasized the usefulness of scales in her composition pedagogy. She noted that the various vertical sonorities and melodic options found within a given scale could be used with great freedom because of their relation to the same pitch constellation, which made them sound inherently logical and musical.

Church Modes

The diatonic or “church” modes share their names with the church modes used during the Medieval and Renaissance periods, but with a different underlying theoretical system. There are seven of these modes, all of which contain seven notes, and these scales – except for the Locrian – have been widely used in European folk music and in 20th century art music. It is possible to write the diatonic modes with any note as the finalis, but for pedagogical reasons they are often shown built on the tones of the diatonic C major scale, as illustrated in the next example. The Roman numerals show the various triad types built on each scale degree of the seven church modes. Observe that the Locrian scale has an unstable diminished triad as the tonic chord, which is why that mode is not often used outside of jazz.

the seven church modes

The following example is in C Ionian and features only root position chords. The avoidance of functional harmonic progression is what distinguishes this from a chord progression in C major and is also what gives it a fresh and unexpected sound.

modal progression

The next examples demonstrate how progressions based on the roots in the circle of fifths progression would appear in several of the church modes. Not featured are the Ionian mode, which has the same chord qualities as the major scale, and the Locrian mode, which has an unstable io chord and is thus little used. Play these at the piano and note the radically different sound the modal harmonies give to each progression. 

Dorian

i – III – vio –  ii –  v – i

                    IV – VII

Phrygian

i – III – VI – II –  vo – I 

                   iv – vii

Lydian

I – iii – vi – II  –  V – I

                  ivo – vii

Mixolydian

I – iiio – vi – ii  –  v – I

                   IV – VII

Aeolian

i – III – VI – iio – v - i

                   iv – VII

Béla Bartók's Mikrokosmos, a collection of nearly two hundred educational piano pieces and exercises, illustrates the use of some of these scales (PhrygianDorianLydian, and Mixolydian) as well as a variety of 20th century compositional techniques. 

Hybrid Scales

It is also possible to create hybrid scales by combining the tetrachords of two different modes. The bottom tetrachord of the Phrygian-Dorian comes from the Phrygian scale, while its top tetrachord comes from the Dorian scale. The bottom tetrachord of the Lydian-Mixolydian comes from the Lydian scale, and its top tetrachord comes from the Mixolydian scale. These hybrid scales further enrich the available sound color possibilities for both melodies and harmonies.

hybrid church modes

Pentatonic Scales

The pentatonic scales have also been used by composers in the 20th century but are more importantly the scales on which so much folk music across the world has been based. The American composer Lou Harrison referred to the pentatonic scale as the “human song” because of its frequent use in folk music from around the globe. The lack of a leading tone and of any m2 intervals in the major pentatonic scale leads to open sounding harmonies and the ability to effectively make any note within the scale the tonal center. These diatonic pentatonic scales occur naturally on the black keys of the piano, and a fun and rewarding experience is to practice “black key improvisation” using only these notes. Even when sounded together, the notes of the major pentatonic scale are not very dissonant because of the lack of half steps and the leading tone.

Any of the five notes in the major pentatonic can serve as the finalis or tonal center of the scale, and these five modes are expressed in the next example.

major mode pentatonic scales

Three other pentatonic scales occur with some frequency. The minor pentatonic is drawn from the natural minor scale (observe that it is the same as mode 5 of the major pentatonic), the Kumoi pentatonic from the Dorian scale, and the Hirajoshi pentatonic from the natural minor scale.

minor mode pentatonic scales

Synthetic Scales

The more commonly encountered synthetic scales include the whole tone and hexatonic scales, each of which has six tones. The hexatonic scale can be looked at as interlocking augmented triads or as a collection of half steps and minor thirds, while the whole tone scale is made entirely of whole steps. Perhaps the most famous use of the whole tone scale is in the outer sections of Debussy’s piano piece Voiles. The middle section of this piece, which is in ternary form, uses only the black key pentatonic scale.

six tone scales

Octatonic scales are further examples of synthetic scales and consist of alternating half and whole steps. The standard octatonic scale exists in two versions or modes, one that begins with a whole step and one that begins with a half step. 

octatonic scales

These synthetic scales and their associated harmonic vertical sonorities have been used by composers since the 19th century, including Nikolai Rimsky-Korsakov, Claude Debussy, Modest Mussorgsky, and Igor Stravinsky. Mussorgsky uses an octatonic scale as the raw material for the harmonies and ostinatos in the Coronation Scene from the opera Boris Gudonov, as exemplified below.

Mussorgsky example

Tetrachords, Pentachords, and Hexachords (Scales)

Tetrachords, pentachords, and hexachords are stepwise groupings of notes. An interesting example of the use of pentachords in a bitonal setting is found in Bartok’s MikrokosmosNo. 86, Two Major Pentachords. The famous hymn Holy Manna features a C pentatonic melody in the tenor in what is an overall Ionian hexachord scale context, with only the treble and alto lines articulating the F and with all voices entirely avoiding the leading tone.

Nonwestern Scales

This text includes just a sample of what is possible when church modes, the scales of Western and non-Western folk music, synthetic scales, and other global resources are used. The possibilities become even greater when using tuning systems other than equal temperament that divide the octave into pitches and intervals not found in modern western scales. For example, the scale formations in traditional African music (BritannicaYouTube) include some that feature more or less evenly spaced divisions of the octave into five, six, and seven note scales. Further examples of such scales include the pelog (YouTube) and slendro (YouTube) scales used in Indonesian gamelan (BritannicaYouTube) music and the ragas (YouTube) of Carnatic (BritannicaYouTube) and Hindustani (BritannicaYouTube) music. Some scales, such as the pelog and slendro, have westernized spellings to fit them into the pitches of the standard chromatic scale, as shown in the list of scales below.

Following are forty-four scales based on the note C4. Some scales are provided with the alternate names that you will at times find in theory texts, on the internet, and in music theory software such as Rising Software's Musition.

scales part 1

scales part 2

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