Modal jazz is jazz played using musical modes rather than chord progressions.

HistoryAn understanding of modal jazz requires knowledge of musical modes. Modes are the seven scales used in medieval music which were 'rediscovered' by composers like Claude Debussy and frequently used by 20th century composers. In bebop as well as in hard bop, musicians used chords to provide the background for their solos. A song would start out with a theme, which would introduce the chords used for the solos. These chords would be repeated throughout the whole song, while the soloists would play their parts. By the 1950s improvising over chords had become such a dominant part of jazz that sidemen at recording dates were sometimes given nothing more than a list of chords to play from. Creating innovative solos became exceedingly difficult.

In the latter 1950s, spurred by the experiments of composer and bandleader George Russell, musicians frustrated with ever repeated chords tried the modal approach. They chose not to write their songs using chords, but instead used modal scales. This meant that the bassist, for instance, did not have to 'walk' from one important note of a chord to that of another - as long as he stayed in the scale being used and accentuated the right notes within the scale, he could go virtually everywhere. The pianist, to give another example, would not have to play the same chords or variations of the chords, but could do anything, as long as he stayed within the scale being used. The overall result was more freedom of expression.

In fact, the way that a soloist creates a solo changed dramatically with the advent of modal jazz. Before, the goal of a soloist was to play a solo that fit into a set of chords. However with modal jazz a soloist must create a melody in one scale (typically), which could be potentially boring for the listener. Therefore, the goal of the musician was now to make the melody as interesting as possible. Modal jazz was, in essence, a return to melody.

Theory

It is possible for the bassist and the pianist to move to notes within the mode that are dissonant with the prime (tonic) chord of that mode. For example: within the ionian mode, the C is the final (prime) note. Other notes such as the note B are dissonant with C, so that they are not used in a non-modal jazz song when playing the chord C. In a modal song these other notes may be used. This means that the notes played will not be recognized as a part of C major.

In modal jazz, among the significant compositions were "So What" by Miles Davis and "Impressions" by John Coltrane. They follow the same AABA song form and were in D dorian for the A sections and modulated a half step up to Eb Dorian for the B section. Dorian mode is the minor scale with a raised sixth.

In improvising within a modal context, a musician would basically start by thinking about playing the notes within that specific mode (e.g., D dorian: D, E, F, G, A, B, C, D). It is also possible to take several notes from that mode (and not all) to create smaller scales or note choices for improvisation. For example, in D dorian, one may play the notes of the D minor triad. This is what Miles Davis does at the beginning of his solo in "So What". The player may even choose any of the triads available in that mode: C maj, Dmin, Emin etc. One thing to note is that choosing an upper structure triad of the chord will result in tension.

The player may also use the many different pentatonic scales within the scale such as C major pentatonic, F major pentatonic and G major pentatonic. Note that these scales are also relative A minor, D minor and E minor pentatonic, respectively.

Compositions

Miles Davis recorded one of the best selling jazz albums of all time in this modal framework. Kind of Blue is an exploration into the possibilities of modal jazz. Included on the songs from these recordings is the tenor horn of John Coltrane who, with, Giant Steps, would begin to explore the possibilities of modal improvisation. This record is considered a kind of test album in many conservatories focusing on jazz improvisation. The compositions "So What" and "All Blues" from Kind of Blue and "Cousin Mary" and "Naima" from the album Giant Steps are considered contemporary jazz standards.