SynthLab help

Getting started

SynthLab is a modular synthesizer and a small studio that run entirely in your browser. You build instruments by patching modules together, play them with the on-screen keyboard, your computer keyboard or a MIDI keyboard, and arrange, mix and export pieces: songs, soundscapes or anything in between.

Every sound in SynthLab is made in your browser by the Web Audio API: oscillators, noise, filters and effects computed as you listen. There are no recordings or samples inside it, apart from the ones you record or load yourself.

Your first sound

Open SynthLab. Browsers only allow sound after you touch the page: click or tap anywhere first.
Play the keys at the bottom of the screen, or your computer keys: A is C, W C♯, S D and so on along the row (Z and X change the octave). The on-screen keys show which letter plays them; Computer keys under the keyboard switches this on and off.
Turn the knobs while you play. Drag up and down (or left and right) on a knob; double-click to reset it; hold Shift for fine steps.
Open Examples in the top bar for soundscapes, demo songs in many styles and ready-made instruments.

Two modes, one project

Both modes share one project. Instruments you save in Modular mode appear in Studio's + Track menu, and ✎ on a Studio track opens its instrument in Modular mode, so you can change the sound while the song plays.

What is on screen

Top bar: the mode switch; the transport (back to start, play/stop, record, loop, metronome, position, tempo, time signature); undo and redo; Examples, Share, File and Help.
Modular: the patch you are editing (the playground, or a track's instrument), + Module, the number of Voices, and Save as instrument.
Studio: tracks and regions on a timeline, and a panel at the bottom with the editors and the mixer. Drag the bar above the panel to make it taller.
Keyboard: piano keys or drum pads, octave, velocity and MIDI. It plays the playground or the selected track.

Keyboard shortcuts

Space	Play / stop (press stop twice to silence everything)
A W S E D F T G Y H U J K O L P	Play notes (from C, black keys on the upper row)
Z · X	Octave down / up
C · V	Softer / louder
R	Record
Shift + L · Shift + M	Loop on/off · metronome on/off
Home	Back to the start (of the loop)
Shift + Tab	Switch between Modular and Studio
⌘/Ctrl + Z · ⌘/Ctrl + Shift + Z	Undo · redo
⌘/Ctrl + S	Save in this browser (it also saves by itself)
Delete	Remove the selected cable, module, region or notes
⌘/Ctrl + D · Shift + S	Duplicate · split the selected region

On a phone

SynthLab opens in Modular mode on phones, with large modules and cables. Pinch to zoom and drag the background to move around. To patch, tap an output and then an input (or drag between them). Knobs turn by dragging up and down. The keyboard has big keys and a set of drum pads; Studio mode works too, in a simpler layout.

Browsers

SynthLab works in current versions of Chrome, Edge, Firefox and Safari (16.4 or newer), on computers, phones and tablets. A few things depend on the browser:

MIDI keyboards need Web MIDI: Chrome, Edge, Opera and Firefox have it; Safari does not. The on-screen keys and the computer keys work everywhere.
Opus export uses the browser's own audio encoder; where a browser has none, only WAV is offered.
On an iPhone or iPad, SynthLab asks to be treated as media playback, so the silent switch does not mute it (iOS 16.4 or newer).

One SynthLab at a time

Only one SynthLab plays at once. When you start an embedded player, the app in another tab stops and pauses its sound engine, and starting another player on the same page stops the first. Tap the message in the paused tab to carry on there. A stopped SynthLab in a background tab pauses its sound engine too, so it uses no processor time.

To keep things light: a stopped SynthLab that has been silent for a few seconds pauses its sound engine (any click, key or MIDI note wakes it); voices that have died away are disconnected until their next note; Studio tracks that are not playing are switched off completely; meters and scopes only run while they are on screen; and very long reverbs (Long reverb, Shimmer) use an algorithmic reverb that costs the same at any length. Embedded players switch to a rendered copy of the piece as soon as it is ready, and so does Studio: see below.

The rendered mix. In Studio, SynthLab renders the whole arrangement in the background when a song opens and a moment after each change (it takes roughly a quarter of the song's length). The chip in the Studio toolbar shows it: Rendering mix 45%, then Mix ready. While the render matches the arrangement, play uses it (Playing rendered mix): it needs almost no processor time and carries on from any point exactly like a recording. Any change, a mute, a knob, a note, switches back to live playback at once (Live), and a new render follows. Renders are kept in this browser and found by a fingerprint of the music, so reopening a song (or playing it in an embedded player) finds its render again, and only a change to the music needs a new one. With the mixer open, playback stays live so the meters move.