Modalism in music may be more natural than the western harmonic systems. I think music is much more naturally "logical" through modes than keys. When modal Jazz came out in the late 50's and proceeded to non-functional harmony by the time of Miles's Sorcerer (I think the "non-functional harmony on Sorcerer is just an unrecognized mode), I feel like there were "sea-change" shifts in North America
An understanding of music theory will helpful when reading this post.
Modality is an interesting phenomenon in that our Western system of music contains 36, seven note scales. At present western music utilizes at most about a dozen or so in an harmonic setting; Ionian/Major, Dorian, Phrygian, Lydian, Mixolydian, Aeolian/Natural Minor, Harmonic Minor, Melodic Minor, and a few of these modes with certain scale degrees altered, i.e. Lydian with a flatted 7th degree being one. In Pop Music one will find mostly Major, Minor, Dorian, Lydian, and Mixolydian depending on style. The mode named Locrian is not used in an harmonic context due to its lack of a solid home base, musically referred to as I or one. (Roman numerals are used to designate harmonic function in scales. The term mode is another name for scale.)
Typically, what is going on in what is called modal music is actually a harmonic device called substitution. Here, a writer is using either Major or Minor as their primary scale and substituting chords, from other modes, that share the same Roman numeral designation.
If, writing in the Key of C Major, the following chord progression is used (I vi ii V I) [Cmaj Amin Dmin Gmaj chords can be borrowed from the other modes to substitute certain chords in the given progression. Let’s substitute chords for vi and ii. Using the mode C Aeolian it will be found that the chord on vi is Aflat major. and the chord on ii is D diminished or Dmin7flat5. The chord progression would now be; Cmaj Aflat-maj Dmin7flat5 Gmaj The Dmin7flat5 chord is richer with the added 7th hence the choice. Arnold Schoenberg discusses this type of modality in his book;
Structural Functions of Harmony
The second type of modality involves the use of one particular mode. Keep in mind that Major and Minor are both individual cases of modality. Using Dorian as the mode, the chord progression will differ from Major, Minor, and other modes in order to define its sound. Major and Minor use an harmonic relationship of I IV V to define the scale. (C Major) Cmaj Fmaj G7 Cmaj. (A Minor) Amin Dmin E7 Amin. A progression using the mode Aeolian; (A Aeolian) Amin Fmaj Gmaj. For Dorian the chord progression that defines this mode will generally be; (C Dorian) Cmin9 Dmin7 Bflat-maj7 Cmin
The third type of modality, used extensively by Jazz composers, is derived from the major/minor system. Standard chord progressions are utilized with each chord taking on the sound of a specific modal scale. This involves what are termed the upper structures of triads and seventh chords. Individual tones of a chord are designated by Arabic numerals as follows; 1 3 5 7 9 11 13. Spoken, they are termed; Root, third, fifth, seventh, ninth, eleventh, thirteenth. In a standard progression such as; (C Major) Cmaj7 Amin7 Dmin7 G7, the 1 3 5 7 are already designated in each chord. This allows the composer to alter the 9 11 and 13 of each chord to sound a different mode at each chordal moment. The 9th and/or 13th might be raised or lowered, the 11th raised. A good resource for learning this type of modal harmony is; Modal Jazz Composition & Harmony by Ron Miller
In 1941 a Russian musician/mathematician, Joseph Schillinger, presented a system of music composition based on mathematical descriptions. This material was first published in book form in 1946 by Carl Fischer Co. This is a two volume, 12 book set. There is a good amount of online information concerning the system. The book is titled;
The Schillinger System of Musical Composition
While studying at Berklee College of Music I was introduced to portions of the system; Theory of Rhythm, and parts of; Special Theory of Harmony, specifically the area of voice leading. I did eventually obtain the set and continue to use it extensively in my writing.
This system was originally taught at Berklee and very popular with Jazz and Commercial composers into the 70’s. More can be found here;
The Schillinger House
In the text Schillinger discusses two ways of creating chord progressions. The first is called; Diatonic System of Harmony, and the second is; Chromatic System of Harmony
Diatonic System of Harmony
1.Choose one of the 36 seven note scales to derive the roots of your chords. Arrange them into a progression.
2.Choose one or two other scales from the 36 for the harmonic structure. All of the chords will be derived solely from the scale or scales chosen.
Chromatic System of Harmony
1.The chromatic scale is used either in ascending or descending order.
(Ascending) C C# D# E F F# G G# A A# B
2. Determine root movement using any number series such as Fibonacci, other additive series, addresses, phone numbers, etc.
3. Starting pitch is composers choice. I’ll start at C and use 1 2 3 5 8 13 (Fibonacci series)
C 1 C# 2 E 3 G 5 C 8 A 13 B
The above is the root movement for perhaps a section of a piece. I can choose any type of chordal structure over the roots of this progression.
Other factors such as voice leading, harmonic rhythm, instrumentation/orchestration, melodization, play a prominent role when utilizing these techniques.
I hope that all of this can help answer some of the questions surrounding compositional techniques utilized by composers.
