Tools Drop pad effects

Drop pad effects

Download fledgetone-drop-effects.zip (36 KB) README.md

Part of Fledgetone (https://fledgetone.com), © Martin Swanson, GPL-3.0-or-later. Source code: https://github.com/martinmswanson-cmd/fledgetone

The effects of Fledgetone's Drop pad, for any web page or browser game: what a DJ does to a whole mix with a finger, held for as long as you hold it, in time with the music.

Effect	What it does
Stutter	Repeats the 16th note that was playing when you pressed
Filter	Sweeps the sound down to a muffle over a bar, and back up when you let go
Tape stop	Slows the sound to a halt over a beat, like a tape machine switched off
Crush	Makes it gritty and lo-fi
Gate	Chops it into 16th notes
Echo	Throws what's playing into a dotted-8th echo that rings on after you let go

Several can be on at once. Every change glides over a few milliseconds, so nothing clicks, and none of them makes the sound louder than it was (apart from the echo's tail).

What's in this zip

File	What it is
`drop-effects.js`	The helper you import (main thread)
`drop-processor.js`	Its AudioWorklet processor
`drop-fx.js`	The effects themselves as a plain JavaScript module (`createDropKernel`), for use without Web Audio, for example to process a buffer
`drop-fx.ts`	The same in TypeScript, as written
`index.html`	An example: a simple beat and a pad for each effect
`LICENSE`	The GNU General Public License, version 3

Try it

Serve this folder and open index.html (AudioWorklets don't run from a file:// page):

npx serve

Use it

import { createDropEffects } from './drop-effects.js';

const context = new AudioContext();
const drop = await createDropEffects(context, { tempo: 128 });
yourMusic.connect(drop.input);
drop.connect(context.destination);

pad.onpointerdown = () => drop.on('Stutter');
pad.onpointerup = () => drop.off('Stutter');

Call	What it does
`createDropEffects(context, options?)`	Makes the effects. Options: `tempo` (BPM, 120 if left out) or `sixteenth` (seconds), `processorUrl`
`input`, `connect(node)`, `disconnect()`	Send the music into `input`; connect the output onwards. `node` is the AudioWorkletNode itself
`on(fx, time?)`	Turn an effect on. `fx` is its name (`'Stutter'`, `'Filter'`, `'Tape stop'`, `'Crush'`, `'Gate'`, `'Echo'`) or number (0 to 5). `time` is on the audio clock, now if left out
`off(fx, time?)`	Let go of it
`cancel(time?)`	Let go of everything and forget what was due after `time` (for a stop or a jump)
`setTempo(bpm)`, `setSixteenth(seconds)`	The music's tempo; effects turned on after this keep time with it
`effects`	The effects' names
`dispose()`	Stop it for good

For effects on the beat, give on the time of the next 16th note of your music rather than now.

Without Web Audio

drop-fx.js exports createDropKernel(sampleRate), the same code the processor runs. Tell it when effects start and stop in samples, then process stereo blocks:

import { createDropKernel } from './drop-fx.js';

const kernel = createDropKernel(48000);
const sixteenth = 48000 * 15 / 120;            // samples in a 16th note at 120 BPM
kernel.on(0, 48000, sixteenth);                // Stutter on at 1 second
kernel.off(0, 96000);                          // off at 2 seconds
kernel.process(left, right, left, right, left.length, 0);   // in place, from sample 0

Licence

These files are free software under the GNU General Public License, version 3 or (at your choice) any later version: GPL-3.0-or-later. The full text is in LICENSE. In plain words:

Free to use, change and share. You can use them for anything, for free, change them, and give them to others, changed or not.
A program that includes them is GPL too. If you share a program that includes these files, or code made from them, you must release that whole program under the GPL as well, and give the people you share it with its source code (or a way to get it).
Keep the notices. Keep this licence and the copyright notice with the files.
No warranty. They come as they are, with no promise that they work for your purpose.
Your music is yours. The licence covers this code, not what you make with it: the music, sounds and songs you make with these tools are yours, to use and share on any terms you like.

This is a summary to help you; the licence text in LICENSE is what counts. Questions or concerns: email martin@twobirdsworkshop.com.