Jazz Overview and Mechanical Performance

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About Jazz

Jazz is a popular entertainment music with its roots in blues and ragtime, which originated spontaneously in New Orleans, Louisiana, a port city in the southern United States facing the Caribbean Sea, at the end of the 19th century, mainly by African Americans, as described in “History of Blues and Automatic Generation by Clojure“. Jazz is characterized by its swing.

Jazz is characterized by swinging rhythms, syncopated rhythms with back notes, complex chords and scales influenced by the blues, and improvisation, but since it was originally “spontaneous” and “entertainment music,” there were no principles or principles, and many musicians added their own ideas. Therefore, it is a music to which many musicians have added their own ideas.

A representative jazz musician is Louis Armstrong, a trumpet player from New Orleans. He inherited the style of “New Orleans jazz,” an early form of jazz in the 1920s, but added his own unique twist to “jazz” by incorporating his own “voice” into his playing.

「ルイ・アームストロングの素晴らしき世界」(サッチモ)の生涯

He has created a unique and appealing droning voice and the realistic and present nuances of a human voice from his instrument, and combined them to create his own style of sound from the trumpet, which in classical music has never added a human touch to the performer, and if it’s appealing, then why not? He showed his fans that it was okay to create one’s own sound if it was appealing. After him, the direction of jazz music as a music that places individual expression first and foremost was established, and has continued to the present day.

Later, in the 1940s, alto saxophonist Charlie Parker In the 1940s, alto saxophonist Charlie Parker developed a new jazz style called “bebop,” which dramatically advanced the “improvisational elements” included in Louis’s “self-styled playing.

チャーリー・パーカー/(現代ジャズへの進化)

Parker’s influence was as strong as Louis’, and most subsequent jazz musicians followed his methods, opening the era of “modern jazz.

This led to the widespread use of “improvised music” in the definition of jazz, but the original idea of Louis was only the expansion of individual expression, and Parker’s highly improvisational playing was also a means of expressing individuality, and improvisation itself is not the purpose or essence of jazz. In Louis’s time, improvisation was limited to adding embellishments or changing parts of the melody line. Parker’s advanced musical knowledge and aesthetic sense allowed him to perform in an extremely thrilling way that only he could do, and he captivated his fans.

The next Miles Davis realized that the improvisation-first approach, in which individual solos were the only thing that could be heard, had its limitations, and that only a genius like Parker could create highly improvised music. He came to believe that a wider range of individual expression is possible through the ensemble sound of multiple instruments.

Miles Davis – Autumn Leaves (Live In Japan 1964 )

This movement led to the later “West Coast Jazz” movement, which adopted Parker’s improvisational principles, but did not focus solely on them. This style of jazz was an evolutionary refinement of “bebop” music.

This new style of jazz music was a consolidation of the commonplace musical form of pursuing a distinctive “sound” while at the same time achieving “musical unity. Miles’ “pursuit of a new sound” led him to adopt a rock sound in the late 1960s.

In addition to the aspect of “pursuit of individuality,” jazz also has a strong aspect of “mixed and fused music. The African American musicians who created jazz grew up in the Latin cultural sphere, and the “Creoles,” who were born to Frenchmen, acquired a background in European classical music. These elements were deeply involved in the birth of jazz.

King Oliver's Creole Jazz Band – Froggie Moore (1923)

As such, jazz, a popular art form that naturally emerged among African Americans, has had a strong character from its birth as a “mixed/fusion music” containing elements of Latin and Western European music, and jazz has become a musical genre with a strong tolerance for “fusion.

This “resistance to fusion” meant that even when elements of diverse musical genres such as Latin, rock, and classical music were introduced, the music was not absorbed into that side of the genre, but instead developed a resilience that allowed it to grow and expand, drawing nourishment from these other genres of music.

Characteristic jazz chord progressions and their implementation with Clojure

As mentioned above, jazz is characterized by rich harmonies and improvisation. Therefore, jazz chord progressions include not only basic triads and seventh chords, but also complex harmonic progressions and inverted chords that are unique to jazz. Typical jazz chord progressions include the following

  1. II-V-I progression: The most basic and common chord progression in jazz, based on the major scale, the II-V-I progression consists of chords in the second, fifth, and first degrees, for example, Dm7 (D minor 7), G7 (G seventh), Cmaj7 (C major 7), etc., in that order.
  2. Blues Progression: Blues-influenced jazz has a 12-bar blues progression, typically consisting of a combination of I7, IV7, and V7 chords. This includes, for example, the C7, F7, and G7 sequences.
  3. Modal Progressions: Jazz uses modes (derivatives of scales) to create harmonic progressions. There are, for example, Dorian, Mixolydian, Lydian, Phrygian, etc. Modes are used in jazz.
  4. Two Five One Progression: An application of the II-V-I progression, constructed by joining several II-V-I progressions together. This progression is often found in jazz standard tunes.
  5. Mode Substitution: Jazz often uses related modes in place of chords to enrich the harmony. This has the effect of creating new tones and chord progressions.
  6. Latin Progressions: The fusion of jazz and Latin music has resulted in distinctive chord progressions. Examples include rhythmic progressions such as bossa nova and samba.

In addition to these, there are endless variations in the world of jazz, and the characteristic harmonic approach of jazz allows musicians to improvise freely and create unique music by utilizing chord progressions.

We will try to implement such jazz chord progressions using Clojure. Overtone, described in “Mathematics, Music, and Computers” is a music programming library based on the Clojure language, and is a tool for synthesizing and playing music. See also “Clojure and Functional Programming” for details on Clojure.

First, install Leiningen (Clojure’s project management tool) and create a project, adding the Overtone dependency to the project.clj file.

(defproject jazz-project "0.1.0-SNAPSHOT"
  :description "Jazz Example Project"
  :dependencies [[org.clojure/clojure "1.10.3"]
                 [overtone "0.10.3"]])

Next, create a file named src/jazz_project/core.clj and write the following code

(ns jazz-project.core
  (:use [overtone.live]))

(defn play-chord [freqs duration]
  (doseq [freq freqs]
    (at-now (* 0.5 (saw freq)))))

(defn -main []
  (boot)

  (def bpm 120)
  (def chord-duration (/ 60 bpm)) ; Length of one beat

  ; Frequency of II-V-I progression
  (def ii-chord [261.63 329.63 392])
  (def v-chord [293.66 369.99 440])
  (def i-chord [329.63 392 493.88])

  (def chord-progressions
    [[ii-chord v-chord i-chord]
     [ii-chord v-chord i-chord]])

  (defn play-progressions [progressions]
    (doseq [chords progressions]
      (doseq [chord chords]
        (play-chord chord chord-duration)
        (Thread/sleep (* chord-duration 1000)))))

  (play-progressions chord-progressions)

  (shutdown))

This code plays a II-V-I progression jazz chord progression using Overtone, and the play-chord function is responsible for taking the frequency and playing time and synthesizing the chord notes. the play-progressions function plays the specified chord progression.

Execution of this code is accomplished by executing the lein run command in the root directory of the project.

However, the “individualized performance” of jazz can be brought closer to the “individualized performance”. By introducing probabilistic models such as those described in “Probabilistic Generative Models” or by using a reinforcement learning framework such as those described in “Overview of Reinforcement Learning Techniques and Various Implementations” can be used to incorporate information from existing experts to create a more “individualized performance.

Reference Book

The Story of Jazz

The Jazz Book: From Ragtime to the 21st Century

 

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