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Jazz & blues
Performance-driven music where harmony, swing feel and instrumental voice matter more than production polish.
Sound and palette
Start by choosing an ensemble size, because it determines everything else. A piano trio (piano, upright bass, brushed drums) is intimate and interactive. A quartet with tenor saxophone adds a lead voice and solo space. A big band brings sectional writing, shout choruses and arranged brass. A blues trio — guitar, bass, drums — is raw and riff-based. Naming the ensemble is a compact way of naming five instruments at once.
Then choose the era or idiom: swing, bebop, cool jazz, hard bop, modal jazz, bossa nova, gypsy jazz, Delta blues, Chicago electric blues, jump blues. Each has a tempo band, a harmonic style and a typical instrumentation, and mixing two of them usually yields neither.
- Keys: acoustic grand, Rhodes, Hammond B3 with Leslie, Wurlitzer.
- Horns: tenor and alto sax, muted trumpet, trombone, clarinet for trad styles.
- Guitar: hollow-body archtop, clean valve amp, slide resonator, Telecaster with spring reverb.
- Rhythm: upright bass walking, brushed snare, ride-cymbal swing, shuffle backbeat.
- Harmonica, washboard and stomp for country and Delta blues colours.
Rhythm, tempo and harmony
Feel must be stated. Swung eighths, straight eighths, shuffle, slow 12/8 blues and bossa clave feel are different grooves that the same tempo can host. A slow blues at 60 BPM in 12/8 and a ballad at 60 BPM in swung 4/4 are entirely different pieces.
Harmony is where jazz prompts can get specific in a way other genres cannot. ii–V–I turnarounds, twelve-bar blues form, modal, one chord for eight bars, rhythm changes and extended chords with ninths and thirteenths all steer the model's note choices. Adding solo section in the middle gives it permission to improvise rather than repeat the head.
| Idiom | Tempo | Feel and form |
|---|---|---|
| Slow blues | 56–72 BPM | 12/8 triplet feel, twelve-bar form |
| Ballad | 60–76 BPM | Swung, rubato intro, brushed drums |
| Bossa nova | 120–140 BPM | Straight eighths, clave-like guitar comping |
| Medium swing | 120–160 BPM | Walking bass, ride swing, head–solos–head |
| Bebop | 180–260 BPM | Fast swung eighths, dense ii–V motion |
| Shuffle blues | 96–132 BPM | Shuffle backbeat, riff-based |
Vocal behaviours
Jazz vocals are about phrasing rather than power. Useful cues: smoky contralto, behind the beat, crooner baritone, warm and close, light scat phrases between lines, breathy, conversational, minimal vibrato. The model responds particularly well to placement instructions — singing behind or ahead of the beat is audible and changes the whole feel.
Blues vocals want grit and repetition: raspy, shouted delivery, call-and-response with the guitar, moaned melisma at the line ends. Blues lyric form is also distinctive — the AAB pattern, where the first line repeats before a resolving third line, is worth writing into your lyrics directly.
Production character and pitfalls
Jazz and blues both sound best with production that gets out of the way: live room, minimal processing, valve amp warmth, mono 1950s recording, tape saturation, natural dynamics, no heavy compression. If you want a modern sound, say so — contemporary jazz production, clean and wide — because the default often lands in a vague mid-century space.
The standard failure modes: asking for "jazz" with no ensemble or era, which produces elevator music; requesting bebop tempos with a slow ballad feel; stacking a big band and a piano trio in one prompt; and specifying pop vocal production over an acoustic ensemble. Another frequent miss is forgetting to ask for solos, which leaves you with a short head repeated four times.
- Name the ensemble, then the era, then the feel.
- Always say swung, straight or shuffle.
- Ask for a solo section explicitly.
- Avoid pop compression cues on acoustic jazz.
- For blues, state the form (twelve-bar) and the vocal grit level.