SB-1 Polysynth · Free online synthesizer

Play a synthesizer, right here in your browser.

Two oscillators, a resonant filter, a full ADSR envelope, an LFO, drive and delay, a real polyphonic synthesizer built on the Web Audio API. No signup, no downloads, nothing to install. Grab a preset, play the keys, and start turning knobs. Headphones recommended.

SB-1 Polysynth
Waveform · time
Spectrum · frequency

VCO-1

80 %
Level
3 vox
Unison
0 %
Noise
CV
Out
SB-1

VCO-2

80 %
Level
14 ct
Detune
Octave
CV
Out
SB-1

VCF

1.2 kHz
Cutoff
1.0
Reso
15 %
Env Amt
In A
In B
CV
Out
SB-1

ENV / VCA

1.1 s
Attack
600 ms
Decay
85 %
Sustain
1.8 s
Release
In
Out
SB-1

LFO

0.4 Hz
Rate
25 %
Depth
Out
SB-1

FX & OUT

0 %
Drive
450 ms
Time
45 %
Feedbk
40 %
Mix
75 %
Volume
In
CV
Main
SB-1
Octave
0 ms
Glide

Keys: A–L white, W E T Y U O black · Hold latches notes so you can tweak knobs while a chord rings · Shift-drag a knob for fine control

A
S
D
F
G
H
J
K
L

How to play it

Click the keyboard at the bottom, or use your computer keys, A S D F G H J K L are the white notes and W E T Y U O the black ones. Start with the presets in the top-right corner of the panel: Dream Pad for slow ambient chords, Wobble Bass for LFO wubs, Acid Lead for squelchy 303-style lines, Pluck for tight melodic stabs. Then break them: every knob responds live while you hold notes.

What all these knobs actually do

This synth is the classic subtractive signal chain: two oscillators make a bright raw tone, the filter carves away harmonics (cutoff = brightness, resonance = the whistle at the edge), the envelope shapes each note in time, and the LFO wiggles whatever you point it at. If any of that sounds like magic words, that's exactly what the course is for, each concept is a short interactive lesson with the same knobs you see here.

Want to actually understand this thing?

Eight free interactive lessons, from "what is sound" to patching a synth like this yourself.

Take the free course →