Jazzband NPM | npm.io

jazzband

This package contains a jazz band that is able to accompany your playing!

Key Features

Grooves that reflect different playing styles
Instruments such as Synthesizer or Sampler
Musicians: Pianist, Bassist and Drummer
Band with Metronome countin
iReal parser
Modular by design
Uses tonal and WAAClock

Installation

npm install jazzband --save

Quick Start

Hello 251

import { Trio } from 'jazzband';
const context = new AudioContext();
const band = new Trio({ context });
band.comp({ chords: ['D-7', 'G7', 'C^7', 'C^7'] }, { bpm: 120 });

The above snippet will setup the default Trio which is a Robot Rhythm Section playing only Synthesizers 🤖 🎹.

Sampler

If you want better sound, try the Sampler Instrument:

import { piano } from 'jazzband/samples/piano';
import { drumset } from 'jazzband/samples/drumset';
// create keys from piano samples with correct offset
const keys = new jazz.Sampler({ samples: piano, midiOffset: 24, gain: 1, context });
// create drums from drum samples
const drums = new jazz.Sampler({ samples: drumset, context, gain: 0.7 });
// pass samplers to trio as instruments
const band = new Trio({context, piano, bass:piano,drums});
band.comp(['D-7', 'G7', 'C^7', 'C^7'], { bpm: 120 });

Rhythm

The first argument of the comp method accepts an array of measures. If you want multiple chords per measure, you can just use arrays:

band.comp([['D-7','G7'],['C^7']]);
// comps two bars

Util

util contains many functions that extend the tonal library by some handy harmony functions.

Intervals

invertInterval(interval): inverts interval, e.g. 2M yields -7m
forceDirection(interval,direction): yields interval that goes in the given direction, e.g. forceDirection('-7M','up') returns '2m' (The target note is the same but the direction is forced)
minInterval: Returns the smallest and simplest interval.
renderIntervals(intervals,root): Render all intervals on the given root

Notes

getNearestNote(from,to,direction?): returns the nearest note (with octave).
getTonalChord(chord) throw in non tonal chords (like -7) => get tonal readable chord

Range

A Range is an array with the lowest note and highest note that can be played.

isInRange(note,range): returns true if the note is inside the given range (array with min max)
transposeToRange(notes, range): will transpose the given notes inside the given range
getRangePosition(note, range): Depends on where the note is inside the given range. e.g. returns 0 for first note 0.5 for middle note and 1 for top note.

Steps

Extend intervals with widely used steps/degrees. The interval to step mapping is:

{
    '1P': ['1', '8'],
    '2m': ['b9', 'b2'],
    '2M': ['9', '2',],
    '2A': ['#9', '#2'],
    '3m': ['b3'],
    '3M': ['3'],
    '4P': ['11', '4'],
    '4A': ['#11', '#4'],
    '5D': ['b5'],
    '5P': ['5'],
    '6m': ['b13', 'b6'],
    '6M': ['13', '6'],
    '7m': ['b7'],
    '7M': ['7', '^7', 'maj7']
};

The first being the more common name.

getStep(step): Returns unified step string. You can pass a number that will be flattened if negative e.g. -2 will output 'b9'.
getIntervalFromStep(step): Returns the interval that leads to the given step.
getStepInChord(note,chord,group?): e.g. getStepInChord('F#','C') yields #11
renderSteps(steps, root): Renders all steps on the given root.

Degrees

A Degree is just a number describing a rough step (no matter if flat/sharp/augmented/diminished). This concept can be helpful to e.g. generate patterns over all kinds of chords (See Patterns).

findDegree(degree, intervals): Returns the given degrees step. e.g findDegree(2,['1P','2m','3M']) is '2m'
hasDegree(degree, intervals): Returns true if the given degree is represented by the intervals.

Symbols

Symbols collect all tonal symbols (chords and scales) to map additional information to them:

short: the chord symbol that should be shown (e.g. △ for M)
long: long name, like humans say it.
groups: groups that the symbol is member of. The groups are provided for all kinds of classification.
scaleNames(group): Returns all scale names that have the given group
chordNames(group): Returns all chord names that have the given group
groupNames(): Returns all group names