Music / 08
Online Synthesizer
A playable subtractive synthesizer in your browser: two oscillators, a resonant filter with its own envelope, ADSR, an LFO, and an arpeggiator, with presets and a link to share your sound.
Online Synthesizer: This is subtractive synthesis, the method behind classic analogue synthesizers: bright waveforms are mixed, then a resonant low-pass filter removes upper harmonics. An envelope opens the filter and shapes the volume over each note, and a low-frequency oscillator adds vibrato, wah, or tremolo. The arpeggiator plays held notes one after another in sixteenth notes at the tempo you set. Runs 100% locally in your browser with zero server file uploads.
- Category
- Everyday tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
Two oscillators feed a resonant low-pass filter, shaped by an attack-decay-sustain-release envelope, with an LFO for vibrato, wah, or tremolo. Play with the mouse, touch, the computer keyboard (Z to M and Q to P), or a MIDI keyboard. Your settings are kept in this browser, and the share link carries them in the address.
Subtractive synthesis in three steps
Start with a harmonically rich wave: a saw contains every harmonic, a square only the odd ones, and a sine none at all. Then take away: the low-pass filter removes harmonics above the cutoff, and raising the resonance boosts the frequencies right at the cutoff, giving the vocal, squelchy edge of classic synth basses. Finally shape it over time with the envelopes.
Detuning two oscillators a few cents apart makes them drift in and out of phase, the thick chorus-like sound of string pads. A slow LFO on the filter adds movement; a fast one on pitch is vibrato.
Using it with other instruments
Record a bass line or arpeggio here and a beat on the online drums, then download both as MIDI and line them up in a music app. For acoustic sounds such as a grand piano, use the online piano, which shares the same keyboard layout.
How to use it
- Pick a preset, or start from the default lead sound.
- Shape it with the oscillator, filter, envelope, and LFO controls while you play.
- Turn on the arpeggiator, record what you play, or copy a link that recreates your settings.
Privacy & limitations
Everything runs in your browser. Settings are kept in this browser, and a shared link carries them in the address, not on a server.
Related tools
Frequently asked questions
What do the controls do?
Wave and detune choose and thicken the raw sound; cutoff sets how much brightness the filter lets through and resonance emphasises the edge; envelope amount makes each note open brighter; attack, decay, sustain, and release shape the volume; the LFO wobbles pitch, filter, or volume.
How do I make a bass sound?
Start from the Deep bass preset: a saw and a square an octave below, a low cutoff with some resonance, and a fast filter envelope, played in the lowest octaves.
Can I save my sound?
Your settings stay in this browser. Copy a link to this sound to keep it elsewhere or share it: opening the link loads the same settings.
Can I play it from a MIDI keyboard?
Yes, in browsers with Web MIDI, such as Chrome and Edge. Press Connect a MIDI keyboard and play.
Free tool · runs in your browser · no account required