Bap is a toolkit for making beats and composing sequences with Javascript and Web Audio for playback in modern browsers. It is inspired by the classic "MPC workflow" and built to make all aspects of beatmaking completely modular and reusable.

Made by Adam Renklint, Berlin april 2015

Install and import

From npm

$ npm install --save bap

From rawgit CDN

<script src="https://cdn.jsdelivr.net/gh/adamrenklint/[email protected]/bap.min.js"></script>

Usage

var bap = require('bap'); // or window.bap

// a kit is like an instrument, or program in mpc terms
var kit = bap.kit();
var oscillator = bap.oscillator({
  frequency: 440
});
// a kit connects infinite slots with infinite layers
kit.slot('Q').layer(oscillator);
kit.slot('W').layer(oscillator.with({ frequency: 330 }));
kit.slot('E').layer(bap.sample('foo.wav'));

// a pattern is a loop made up of channels and notes
var pattern = bap.pattern();
pattern.channel(1).add(
  ['1.*.01', '1Q', 48, 70, 0, -50],
  ['1.2.01', '1W', 96, 100, 0, 50],
  ['1.4.01', '1E']
);

// connect the kit, and play
pattern.kit(1, kit).start();

Basic concepts

• Bap runs at 96 ticks per beat, with a position signature like MPC: bar.beat.tick
• Kits are like instruments (programs in MPC terms) and contains infinite slots, each with infinite layers of samples and oscillators
• Patterns are playable collections of channels containing notes, and connect with kits
• Notes are defined by six main parameters: position, target, duration, volume, pan and pitch
• Only position and target params are required, all others can be null/falsy/undefined
• Positions containing expressions are automatically expanded
• When a layer is played, it merges the params of the note, channel, layer, slot and kit

Known issues

• Creating effect nodes on-the-fly is not performing well in Firefox, resulting in clipping on the initial run of a pattern

Resources

• Changelog
• Examples
  • Metronome
  • Boombap beat
  • Sample slices
  • Multi-layered sequences
• Related links

API

• All objects are based on ampersand-state
• on(name, callback) register event callback
• off(name, [callback]) unregister event callback
• once(name, callback) register single-run event callback
• with(params) return a clone of itself with params
• toJSON() return current params as JSON

bap

• clock reference to clock singleton
• volume number between 0 and 999, master volume setting, defaults to 100
• kit(params) returns a new kit
• slot(params) returns a new slot
• layer(params) returns a new layer
• oscillator(params) returns a new oscillator
• sample(params) returns a new sample
• pattern(params) returns a new pattern
• sequence(sequence..., params) returns a new sequence
• channel(params) returns a new channel
• note(params) returns a new note
• reverb(params) returns a new reverb
• delay(params) returns a new delay
• compressor(params) returns a new compressor
• overdrive(params) returns a new overdrive
• filter(params) returns a new filter
• chorus(params) returns a new chorus
• phaser(params) returns a new phaser
• pingpong(params) returns a new [ping pong delay](#ping pong delay)
• new() returns a new instance of Bap, with its clock and event bus separated from other instances

params

• mute boolean, defaults to false
• volume number between 0 and 999, defaults to 100
• length number, length in seconds, overriden by duration if shorter
• duration number, duration in ticks, overriden by length if shorter
• attack number, attack in seconds
• release number, release in seconds
• pitch number between -999 and 999 representing the pitch shift in semitones, defaults to 0
• pan number between -100 and 100, defaults to 0

events

• started triggered on Note, Channel, Pattern, Kit, Slot and Layer when sound source starts playing
• stopped triggered on Note, Channel, Pattern, Kit, Slot and Layer when sound source stops playing

clock

• playing boolean, current state of playback, can be changed to start or pause
• position string in format bar.beat.tick, can be set to move playback position
• bar, beat, tick numbers, equal and bound to position, can be set to move playback position
• tempo number, current tempo of playback, read only
• step function, called on each step with note and time as arguments, able to cancel step by returning false
• sequence pattern or sequence currently playing
• start() start playback, if current pattern is set
• start(pattern) set current pattern and start playback
• pause() stop playback
• stop() stop playback and set position to 1.1.01

kit

• slot() returns blank slot assigned to next id
• slot(id) returns existing or blank slot with id
• slot(id, slot) assign slot instance to id
• slot(slot) assign slot instance to next id
• connect(effect) route output signal to destination via effect or chain
• bypass boolean to bypass all effects, effect type string or array of strings to bypass specific effect types, defaults to false

slot

• layer() returns a blank layer assigned to next id
• layer(id) returns existing or blank layer with id
• layer(id, layer) assign layer instance to id
• layer(layer) assign layer instance to next id
• layer(sampleSrc) returns a new sample layer, assigned to next id
• start(time, [params]) start playback of slot at (AudioContext) time
• start([params]) start playback of slot immediately
• stop(time, [params]) stop playback of slot at (AudioContext) time
• stop([params]) stop playback of slot immediately
• connect(effect) route output signal to destination via effect or chain
• bypass boolean to bypass all effects, effect type string or array of strings to bypass specific effect types, defaults to false

layer

• start(time, [params]) start playback of slot at (AudioContext) time
• start([params]) start playback of slot immediately
• connect(effect) route output signal to destination via effect or chain
• bypass boolean to bypass all effects, effect type string or array of strings to bypass specific effect types, defaults to false

oscillator

• frequency number, frequency of oscillation in hertz, defaults to 0
• note string, note identifier like C3 or a4 - if set, overrides frequency
• shape string, shape of waveform, defaults to sine, other values are square, sawtooth, triangle and custom

sample

• src string, url used to load sample buffer
• offset number, starting point offset in seconds, defaults to 0
• channel string, defines how to handle stereo buffers: left or right uses a single channel, merge and diff combines or differentates between channels, default is null and does nothing
• reverse boolean, reverse buffer or slice of buffer
• loop number, loop length in seconds, defaults to 0 i.e. not looping
• slice(pieces) returns a kit with the sample sliced into even-sized sections
• bitcrush number between 0 and 16, resamples waveform to defined bit depth, defaults to 0, i.e. no resampling
• bitcrushFrequency number between 20 and 22050, normalization frequency at which to apply the bitcrusher effect, defaults to 6500
• bitcrushMix number between 0 and 100, ratio of wet bitcrushed signal to mix with dry signal, defaults to 50
• trimToZeroCrossingPoint boolean, automatically trim sample start and end to zero crossing point to avoid clipping, defaults to true

pattern

• playing boolean, current state of playback, can be changed to start or pause
• tempo number, playback tempo in bpm, defaults to 120
• bars number, length of pattern in bars, defaults to 1
• beatsPerBar number, amount of beats per bar, defaults to 4
• loop boolean, define if pattern should loop, defaults to true
• volume number between 0 and 999, master volume for pattern, defaults to 100
• transform function to be called after expanding position expressions into notes, called after channel.transform
• channel() returns a blank channel assigned to next id
• channel(id) returns existing or blank channel with id
• channel(id, channel) assign channel instance to id
• channel(channel) assign channel instance to next id
• start() start playback of pattern
• pause() stop playback
• stop() stop playback and set position to 1.1.01
• kit(id, kit) connect kit to id
• kit(id) return kit connected to id
• then(sequence, ...) return new sequence with passed sequences and patterns after pattern
• after(sequence, ...) return new sequence with passed sequences and patterns before pattern
• and(sequence, ...) return new sequence with passed sequences and patterns layered with pattern

sequence

• constructor(sequence, ..., [params]) the sequence constructor optionally takes any number of sequences and patterns as argument before the usual params
• playing boolean, current state of playback, can be changed to start or pause
• loop boolean, define if sequence should loop, defaults to false
• sequences an array of sequences, patterns or arrays of sequences and patterns
• bars number, length in bars, read-only
• then(sequence, ...) return new sequence with passed sequences and patterns after sequence
• after(sequence, ...) return new sequence with passed sequences and patterns before sequence
• and(sequence, ...) return new sequence with passed sequences and patterns layered with sequence

channel

• transform function to be called after expanding position expressions into notes, called after note.transform, can return false to not execute pattern.transform
• add(note, note, ...) schedule note(s) to be played within context of channel
• connect(effect) route output signal to destination via effect or chain
• bypass boolean to bypass all effects, effect type string or array of strings to bypass specific effect types, defaults to false

note

• transform function to be called after expanding position expressions into notes, called before channel.transform, can return false to not execute channel.transform
• start([time]) start playback of note at (AudioContext) time or immediately
• stop([time]) stop playback of note at (AudioContext) time or immediately
• connect(effect) route output signal to destination via effect or chain
• bypass boolean to bypass all effects, effect type string or array of strings to bypass specific effect types, defaults to false

reverb

• wet number between 0 and 999, amount of wet signal, defaults to 30
• dry number between 0 and 999, amount of dry signal, defaults to 100
• time number, impulse time in seconds, defaults to 1
• decay number, drop off time in seconds, defaults to 3
• filter string, type of filter (highpass, lowpass, bandpass, lowshelf, highshelf, peaking, notch, allpass), defaults to highpass
• cutoff number, frequency where filter is applied, defaults to 2000
• reverse boolean, defaults to false
• bypass boolean, defaults to false

delay

• wet number between 0 and 999, amount of wet signal, defaults to 50
• dry number between 0 and 999, amount of dry signal, defaults to 100
• sync boolean, sync delay with current tempo, defaults to false
• time number between 0.001 and 4, delay time in seconds (or beats if sync is true), defaults to 0.3
• feedback number between 0 and 999, amount of regeneration from processed signal, defaults to 50
• filter string, type of filter (highpass, lowpass, bandpass, lowshelf, highshelf, peaking, notch, allpass), defaults to highpass
• cutoff number, frequency where filter is applied, defaults to 2000
• bypass boolean, defaults to false

compressor

• threshold number between -100 and 0, decibel value above which the compression will start taking effect, defaults to -12
• knee number between 0 and 40, decibel value representing the range above the threshold where the curve smoothly transitions to the compressed portion, defaults to 30
• ratio number between 0 and 20, amount of change in dB needed in input for 1 dB change in the output, defaults to 12
• attack number, seconds required to reduce the gain by 10 dB, defaults to 0
• release number, seconds required to increase the gain by 10 dB, defaults to 0.25
• gain number between 0 and 999, amount of gain to processed signal, defaults to 100
• bypass boolean, defaults to false

overdrive

• wet number between 0 and 999, amount of wet signal, defaults to 50
• dry number between 0 and 999, amount of dry signal, defaults to 50
• preBand number between 0 and 100, amount of preband filtering, defaults to 50
• color number between 20 and 22050, frequency cutoff for preband filtering, defaults to 800
• postCut number between 20 and 22050, frequency cutoff for post filter, defaults to 3000
• gain number between 0 and 999, amount of gain to processed signal, defaults to 100
• bypass boolean, defaults to false

filter

• based on BiquadFilterNode
• wet number between 0 and 999, amount of wet signal, defaults to 50
• dry number between 0 and 999, amount of dry signal, defaults to 50
• shape string, type of filter (highpass, lowpass, bandpass, lowshelf, highshelf, peaking, notch, allpass), defaults to highpass
• frequency number between 20 and 22050, frequency at which to apply effect, defaults to 440
• q number between 0.001 and 100, controls the frequency band width or peak at cutoff, defaults to 1
• value number between -999 and 999, amount of gain to affected frequency band, defaults to 0
• gain number between 0 and 999, amount of gain to processed signal, defaults to 100
• bypass boolean, defaults to false

chorus

• wet number between 0 and 999, amount of wet signal, defaults to 50
• dry number between 0 and 999, amount of dry signal, defaults to 50
• rate number between 0.01 and 99, defaults to 1.5
• feedback number between 0 and 999, defaults to 0.2
• delay number between 0 and 1, defaults to 0.005
• gain number between 0 and 999, amount of gain to processed signal, defaults to 100
• bypass boolean, defaults to false

phaser

• wet number between 0 and 999, amount of wet signal, defaults to 50
• dry number between 0 and 999, amount of dry signal, defaults to 50
• rate number between 0.01 and 99, defaults to 1.5
• depth number between 0 and 1, defaults to 0.3
• feedback number between 0 and 999, defaults to 0.2
• stereoPhase number between 0 and 180, defaults to 45
• modulationFrequency number between 500 and 1500, defaults to 750
• gain number between 0 and 999, amount of gain to processed signal, defaults to 100
• bypass boolean, defaults to false

ping pong delay

• wet number between 0 and 999, amount of wet signal, defaults to 50
• dry number between 0 and 999, amount of dry signal, defaults to 50
• feedback number between 0 and 1, defaults to 0.2
• left number between 0.001 and 10, left channel delay in seconds, defaults to 0.15
• right number between 0.001 and 10, right channel delay in seconds, defaults to 0.2
• gain number between 0 and 999, amount of gain to processed signal, defaults to 100
• bypass boolean, defaults to false

Feedback and issues

• Report bugs with Github Issues
• Ask questions on Gitter
• Send shoutouts on Twitter
• Or just email me

Develop

• npm install install all dependencies
• npm start run examples development server
• npm test run tests
• npm run test:watch run and watch tests
• npm run coverage generate coverage report with Istanbul
• npm publish run tests, publish to npm, build minified version, tag and deploy examples

Contribute

• Check the roadmap and open issues
• Fork the repo
• Add tests and/or examples
• Submit a pull request

Props

• Roger Linn for making MPC60
• Marley Marl for innovating the art of sampling
• DJ Premier, J Dilla, Pete Rock, Damu the Fudgemunk, Black Milk, Large Professor and Apollo Brown for making dope beats to be inspired from
• Matt McKegg for building Bopper and Ditty, which are used in this project since version 0.1

License

MIT © 2015 Adam Renklint

Generated with redok @ Monday June 19th, 2017 - 10:10:57 AM