Definition
In most small-group jazz performances (from bebop onward) the piece follows the head – solos – head scheme:
- the theme (head) is played once or twice;
- each soloist improvises one or more choruses, that is, complete passes through the form of the piece (12 bars for a blues, 32 for an AABA);
- the theme returns (head out) and the piece closes with an ending.
It is essentially a theme and variations in which the variations are improvised and the "fixed structure" is the chord sequence (the changes) and the form.
The sections of a typical performance
| Section | Length | What happens |
|---|---|---|
| Intro | 4–8 bars | solo piano, drums, a vamp on the ii–V, the last bars of the form, or a written intro |
| Head in | 1 chorus (blues often 2 times) | theme in unison or harmonized; rhythm section in "two feel" or in four |
| Solos | 1–n choruses per soloist | typical order: horns, then guitar/piano, then bass; the comping adapts |
| Trading fours / eights | 1–2 choruses | soloists and drummer alternate every 4 or 8 bars |
| Head out | 1 chorus | theme, often with a different last A |
| Ending | variable | tag, vamp, cadenza, held chord |
Arrangement tools
- Two feel → four feel: in the theme the bass plays half notes (two beats per bar), in the solos it moves to a walking bass in quarter notes: a simple way to raise the energy.
- Shout chorus (big band): a written chorus for the whole band after the solos, with maximum density.
- Backgrounds / soli: horn figures behind a soloist (repeated riffs).
- Send-off: 2–4 written bars that "launch" the first soloist.
- Stop-time and breaks: the rhythm section stops, the soloist plays alone for 2 or 4 bars (the "break" before the first chorus, typical of bebop themes).
- Interlude: a written section between one soloist and the next, often a vamp.
The most common endings
- Tag: the last 2–4 bars are repeated (often substituting the I with a iii or a ♯iv°: | Em7 A7 | Dm7 G7 | repeated three times, then I).
- Fermata on the last chord with free improvisation.
- Final vamp with a fade.
- "Basie" ending: after the theme, three piano notes and a short, dry band chord.
- Cadenza ending: ritardando with ♭VI7 – ♭II7 – Imaj7.
Arrangement example (blues in F, 12 bars, ♩ = 160)
- Intro: 4 bars (last 4 of the form) piano and drums.
- Head: 12-bar theme ×2, bass in two feel.
- Solos: tenor sax 3 choruses, trumpet 2, piano 2 (walking bass).
- Trading fours: 2 choruses with the drums.
- Head out ×2.
- Ending: tag of the last 4 bars repeated twice and a held F13 chord.
Famous examples
- Miles Davis, "So What" (Kind of Blue, 1959): piano and bass intro, AABA theme with "call and response" between bass and horns, solos by Miles, Coltrane, Adderley, Evans, head out.
- Sonny Rollins, "St. Thomas" (1956): calypso theme, solos with a shift from the Latin groove to swing.
- John Coltrane, "Giant Steps" (1960): 16-bar theme, solos over cycles of major thirds.
How to analyze it by listening
- Find the form of the piece (count the bars of the theme).
- Note the starting time of each chorus and who is playing.
- Mark the feel changes (two/four, Latin/swing), the dynamics, the background figures.
- See how the ending connects to the beginning (often the intro returns as a coda).
For a producer
The head–solos–head logic is useful outside jazz too:
- in an instrumental track (lo-fi, jazz-hop, neo-soul) present the theme, then leave 1–2 passes to a "soloist" (synth lead, guitar, sampled sax), then return to the theme;
- use the two feel → four feel shift as an energy increase (bass at half values in the first section, at full values in the second);
- close with a tag (the last 2 bars repeated three times) instead of a fade.
Related entries
Theme and variations, Blues forms, The American 32-bar song form, Rhythm changes as a form, Walking bass: building jazz lines, Analysis of a jazz tune from a lead sheet.