mcp_opendaw_create_ground_bass
Create a repeating bass ostinato with a developing melody line. Choose from baroque, modal, minimalist, film tension, or folk styles to generate a ground bass pattern for your track.
Instructions
Create a ground bass — a repeating ostinato bass line with optional melody.
The ground bass (basso ostinato) is one of the oldest composition techniques: a short bass pattern repeats throughout the piece while melodies above it change and develop. Used in baroque (Purcell's Dido's Lament, Bach's Crucifixus), chaconne/passacaglia tradition, jazz modal vamps, and film scoring (repeating tension ostinati).
Unlike passacaglia (which generates variations above the bass), ground_bass creates the pure repeating bass ostinato + a melody line that develops over the repetitions. The melody changes character per repetition cycle.
melody_styles: "baroque" — Stepwise descending lines over the ground. chromatic passing tones, suspensions on strong beats. Purcell/Bach style. Melody descends gradually across repetitions. "modal" — Modal jazz vamp style. Long sustained notes, sparse placement, emphasis on chord tones. Miles Davis / Kind of Blue aesthetic. Melody floats above the bass. "minimalist" — Steve Reich / Philip Glass style. Phase-shifted melodic fragments, repetitive cells, gradual transformation. Melody uses small intervals and repeating patterns. "film_tension" — Dark film scoring style. Minor 2nd and tritone intervals, dissonant suspensions, gradual crescendo. Melody builds tension across repetitions. "folk" — Strophic folk variation style. Pentatonic-leaning melody, simple rhythmic values, phrase repetition with slight variation. Celtic / English folk tradition.
Args: bass_pattern: Space-separated bass notes (e.g. "A2 E2 C2 G2"). Can use note names (A2, C3) or MIDI numbers (45, 52). bass_rhythm: Space-separated durations in beats for each bass note (e.g. "2 2 2 2" = 4 notes each lasting 2 beats = 8-beat cycle). repeats: Number of bass repetitions (2-32). melody_style: Melody character above the ground. unit_index: AU index. track_index: Note track index (bass goes here, melody on track_index+1). start_beat: Starting beat position. velocity: Base velocity 0-1.
Returns bass notes created, melody notes, cycle info, and style.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| repeats | No | ||
| velocity | No | ||
| start_beat | No | ||
| unit_index | No | ||
| bass_rhythm | No | 2 2 2 2 | |
| track_index | No | ||
| bass_pattern | No | A2 A2 E2 E2 | |
| melody_style | No | baroque |
Output Schema
| Name | Required | Description | Default |
|---|---|---|---|
| result | Yes |