Describe the role and application of pedal points and ostinatos in jazz arranging, providing examples of their use in well-known arrangements.
Pedal points and ostinatos are powerful arranging techniques used in jazz to create harmonic stability, rhythmic drive, and a sense of continuity. While both involve a repeating element, they differ in their nature and application. A pedal point is a sustained or repeated note, typically in the bass, that remains constant while the harmony above it changes. An ostinato, on the other hand, is a short melodic or rhythmic pattern that is repeated persistently throughout a section of music, and can be placed in any voice. These techniques can be combined or used separately to create a wide range of musical effects.
Pedal points create a sense of harmonic tension and release by providing a constant reference point while the harmony moves around it. Usually, the pedal note is a tonic, dominant, or subdominant note in a key. As the chords change above the pedal point, it creates a unique and colorful harmonic landscape. The use of a tonic pedal creates a feeling of stability and can help reinforce the sense of key. When a dominant pedal is used, a sense of unresolved tension is created, making the resolution to the tonic more powerful. The subdominant pedal is less common but can create a softer, more reflective harmonic environment. The harmonic interest is generated by the contrast between the unchanging pedal note and the changing chords above it. For example, if a C pedal is placed in the bass while a progression like Dm7-G7-Cmaj7 moves above it, the C will sometimes be a chord tone of the current chord and sometimes not. The fact that it is not a chord tone during the Dm7 and G7 gives the chord a particular unique sound. It adds a layer of depth and harmonic complexity. Pedal points are often found in the bass or low register, but they can also be placed in the middle register or even a higher register, adding a unique color.
Ostinatos are short melodic or rhythmic patterns that repeat continuously, creating a rhythmic and sometimes melodic foundation for other musical elements to be built upon. Ostinatos provide a sense of forward motion and continuity and help to build a musical texture. Unlike pedal points that are limited to a single note, ostinatos can be longer and more complex phrases. Ostinatos can be melodic, meaning they contain various notes or they can just be rhythmic patterns that are repeated. They can also be placed in any part of the band or ensemble, unlike pedal points, which are most often placed in the bass register. Ostinatos are often simple and repetitive, and this simplicity creates a strong rhythmic foundation. For example, an ostinato pattern of eighth notes in a piano comping pattern or a bassline can create a driving rhythm section, and a melodic ostinato in a horn line can establish a motif or theme that is repeated throughout the arrangement. Ostinatos add a sense of continuity, which helps to unify the different sections of a piece, and can be layered upon each other, to create a more complex musical texture.
Now let's consider specific examples of their use in well-known jazz arrangements:
1. "So What" by Miles Davis: In this modal jazz classic, the bass plays a D pedal point during the main A section. The underlying harmony is actually a D minor 7th chord, and the fact that the bass maintains a pedal point of D creates a very stable feeling and allows the soloists to explore the modal harmonies above it. It also creates a sense of tension when the harmony shifts to Ebm7, since it’s not a diatonic chord, creating a feeling of harmonic ambiguity. This is a great example of how pedal points can be used in modal jazz to create a more spacious and harmonically interesting soundscape. The pedal point provides a solid foundation for the soloists to improvise.
2. "Take Five" by Dave Brubeck: The famous piano part in "Take Five" features an ostinato pattern in the left hand. This ostinato is a simple pattern based on a descending chromatic scale that loops repeatedly. This rhythmic ostinato provides the rhythmic and harmonic foundation of the piece, and it also creates a sense of rhythmic interest by using a 5/4 time signature. This ostinato helps provide the distinctive sound of this famous song. The ostinato helps to maintain the complex time signature, acting as a rhythmic guide through the song.
3. "Spain" by Chick Corea: This piece uses both pedal points and ostinatos. The song features a pedal point on A that is used throughout the introduction and main sections. Also, there are multiple ostinatos being played at the same time. The piano, bass and drums all feature their own unique ostinato patterns. This gives the song a strong sense of rhythmic drive and harmonic complexity. The combination of both pedal points and ostinatos helps to create the signature sound of this piece.
4. "A Night in Tunisia" by Dizzy Gillespie: This song frequently uses a pedal point of D, while also utilizing an ostinato of repeating patterns in the percussion and piano. This rhythmic ostinato creates the rhythmic pulse, and the pedal point creates an underlying harmonic framework. The combination of the two helps to create a sense of forward motion and excitement. These rhythmic elements give the song an energetic feeling.
In summary, pedal points and ostinatos are crucial arranging techniques in jazz, creating rhythmic, melodic and harmonic interest. Pedal points establish a sense of harmonic stability and tension, while ostinatos create a sense of rhythmic and melodic drive. Used individually or in combination, these techniques give jazz arrangers a wide palette for creating rich and unique musical textures. The use of these elements is what makes many jazz standards and pieces sound so interesting and unique.