JS-130

A synthesizer and sequencer that runs in your browser, using the WebAudio API.

Try it out here: https://www.joelstrait.com/jssynth/

Example Song

The song below is an example of what you can create with the JS-130, along with Beats Drum Machine and GarageBand.

JS-130 Example Song

Features

• Oscillator Instruments
  • Base oscillator with sine/square/saw/triangle wave
  • Secondary oscillator with same wave types, and optional detune from primary oscillator
  • White or pink noise
  • Adjustable volume for each noise source (oscillator 1, oscillator 2, noise)
  • LFO to control oscillator pitch (i.e. "pitch wobble")
  • Filter, with LFO and ADSR envelope to control filter cutoff frequency
  • ADSR Envelope to control loudness
  • Feedback delay and reverb effects
• Sampler Instruments
  • Use a sound file (*.wav, *.mp3, etc.) as an instrument
  • Filter, with LFO and ADSR envelope to control filter cutoff frequency
  • ADSR Envelope to control loudness
  • Feedback delay and reverb effects
• Sequencer
  • Multiple tracks, each with its own instrument and set of patterns
  • Enter notes in patterns via on-screen piano keyboard, MIDI keyboard, or computer's keyboard
  • Full songs 1-99 patterns long
  • Volume control + mute for each track
• Tempo control
• Master volume control
• On-screen keyboard to enter notes and try out sounds
• MIDI keyboard support (only in browsers that support Web MIDI, such as Chrome)
• Download sequencer output to a *.wav file

Building / Running Locally

• If first time building, run yarn install
• Run yarn build-dev, which will build the app in the dist/ folder
• Open dist/jssynth.html in your browser (make sure running a local server such as MAMP)
• To automatically rebuild when source files change, run yarn run build-dev --watch instead

Building Production

• Run yarn build-prod
• dist/ folder will contain the files that should be deployed to production

Screenshots

Sequencer:

Instrument editor:

Pattern editor: