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IB Musical Investigation Web Site
Musical Structure and Style


The Origins
The Purpose
Musical Structure and Style
References and other Links

Bebop is characterized by lightning fast tempos, compound harmonies and elaborate melodies. Many Bebop artists took existing songs and worked more intricate and thrilling melodies over them while using chord substitutions for regular changes. If there was more than one horn player, then these musicians would generally play the revamped melody in unison before breaking away to improvisational solos. Bass players would 'walk' at the speedy tempos, which means creating a bass line from the notes in the chord changes and their corresponding scales while playing on every quarter note. Drummers would also keep the steady beat by riding the high hat.

Soloists in Bebop would generally stay to the scales derived from the chords. Since the changes were generally dominant seven chords, the seventh tone of the scale was lowered a half step. In the Bebop scale both the lowered seventh and natural seventh are played. This, along with the blue notes of the flat fifth and flat ninth often used in many chords, created chromatically oriented solos where almost every tone of the twelve tones could be played at least in passing. Although Bebop improvisation was full of notes and running licks, the spacing was very important and motifs were established within and developed throughout solos. Soloists would play chorus after chorus until they were ready to finish and then the next musician would improvise. After everyone had soloed, the musicians would trade fours with the drummer (trade sequential four bar solos) and/or return to the melody and finish the song.

There are four main components to an opera: recitatives, arias, overtures and librettos.

The recitatives are the parts of the opera that are used to further the plot. They contain either a monologue or a dialogue spoken in regular speech. They seldom introduce a musical line and are more like quick monotone chatter or question and response dialogue that increases tension. Recitatives may be accompanied by a full orchestra or by continuo.

Arias are the lyrical and melodic musical pieces of the opera. They are the especially memorable parts of the opera, the big numbers where the singer reveals emotion and presents their best voice. The soloist usually sings them in an A-B-A format called the da capo aria.

The overture is the largely instrumental section heard usually as a prelude or introduction to the opera. Acts are generally commenced by overtures in which melodies from approaching arias are first presented.

The libretto is the screenplay or script of the opera. Written by a librettist, the libretto provides characters and fantastic plot to operas to enhance and inspire the theme of the music. The drama and fluidity that arise from the libretto coincide with the rhythm, melody, and mood of the music.