An online synthesizer is a synth whose oscillators, filters and envelopes are computed by your browser instead of by an installed plugin. Same architecture, same maths, same signal path - the difference is that it opens in a tab. Play the one below with your keyboard before you read another sentence about it.
This is a subtractive voice: two sawtooth oscillators detuned against each other, running into a resonant lowpass with an envelope on the cutoff. That is the same block diagram as a Minimoog, a Juno or any soft synth in your plugin folder - executed here by the browser, with nothing downloaded. Hold two notes and listen to the detune beat against itself.
Learn these once and every synthesizer - hardware, plugin or browser - stops being mysterious.
The sound source. A sawtooth has every harmonic and sounds bright and buzzy; a square has only odd harmonics and sounds hollow; a sine has none and sounds like a whistle. Detuning two oscillators by a few cents is what turns a thin tone into something wide - that beating you hear in the brick above is two saws disagreeing about pitch.
A lowpass removes harmonics above a cutoff point, which is how you get from buzzy to warm. Resonance boosts the frequencies right at the cutoff, and past a certain amount the filter starts singing on its own. Almost every sound you think of as "synthy" is a filter moving.
Attack, decay, sustain, release - how loud the sound is over time. A fast attack and short decay is a pluck; a slow attack and long release is a pad. Point that same envelope at the filter cutoff instead of the volume and you get the classic sweep.
A low-frequency oscillator is an oscillator too slow to hear, used to move something else: pitch for vibrato, amplitude for tremolo, cutoff for a wobble. A modulation matrix is simply a table of what moves what, and it is where a preset becomes a patch.
One voice plays one note. Sixteen voices play a sixteen-note chord, or eight notes with their releases still ringing. Voice count is the single biggest driver of CPU cost in any synth, browser or not.
Reverb, delay, chorus, distortion - added after the voice, shared by all of them. They are not part of the synthesis, but they are most of the reason a patch sounds finished.
Different engines, not skins on the same one. Pick by the sound you are chasing.
| Synth | Engine | Best for | The one thing it does that the others cannot |
|---|---|---|---|
| <strong>Quantum Synthesizer X</strong> | Wavetable, dual oscillator | Modern leads, evolving pads, bass | A 4-slot modulation matrix and a wavetable position you can automate |
| <strong>Analog Synth</strong> | Subtractive, 2 osc + resonant filter | Classic basses, brass, plucks | The straight vintage signal path with nothing in the way |
| <strong>Wave Rider</strong> | Draw-the-waveform, unlimited layers | Melodies without playing keys | You draw a shape and it becomes a scale-locked melody |
| <strong>Modern Piano</strong> | 4 sound engines | Keys, Rhodes-style electrics, hybrids | Chord detection while you play |
| <strong>Theremin</strong> | Continuous X/Y control, 4 waveforms | Glissandi, sci-fi, expressive lines | No discrete pitches at all - the gesture is the instrument |
Everything sounds better once you have taken something away. Pull the cutoff down until the sound goes dull, then bring it back until it is just bright enough.
Short attack, medium decay, low sustain. This one move turns a flat drone into a pluck, and it is the single most useful thing in subtractive synthesis.
Not more. Past thirty cents it stops sounding wide and starts sounding out of tune - the line between the two is narrower than people expect.
Find the point where the filter starts to sing, then retreat about a third. That is where the sound has character without taking over the mix.
Reverb flatters everything. Judge the patch dry, then add the effect - otherwise you will keep a patch that only works alone.
The brick above is one voice. These are the full instruments, all inside the same subscription.
There are two very different things sold under this name. The first is a keyboard that triggers recorded samples: press a key, hear a file. It is useful for a demo and useless for sound design, because there is nothing to shape. The second is a real synthesis engine - oscillators generating waveforms in real time, a filter you can sweep, envelopes and modulation you can point at anything. Only the second one is a synthesizer in the sense a producer means it, and only the second one is what runs on this page.
The Web Audio API is a node graph executed in the browser's native audio thread: oscillators, biquad filters, waveshapers, convolution reverb, dynamics, all scheduled against a clock accurate to the sample. Custom DSP runs in an AudioWorklet on that same thread rather than competing with the page. The consequence is blunt - the parts of a synthesizer that have to be fast are not written in JavaScript, and have not been for years. The browser-based DAW page goes through the engineering objections one by one.
A browser cannot host VST or AU binaries, so an online synthesizer is the engine it ships with and nothing else. If your sound depends on one specific plugin, no browser synth replaces it - that case is worked through honestly on the VST alternatives page. You also cannot dial a 64-sample buffer the way an ASIO driver can, which matters if you are tracking a live performer and matters very little if you are writing.
Plenty of online synths are free because they are one oscillator and a demo. GOONS is not free: the whole studio - every synth, the drum machines, the samplers, the effects, the sample library and cloud projects - is €9.90 a month, with seven days of full access first and no card to start. That trade-off is argued in full on the free music software page, including the parts of it that favour the free tools.
A synthesizer whose sound is generated in real time by your web browser rather than by installed software. Oscillators, filters, envelopes and modulation all run on the Web Audio API, so the architecture is the same as a plugin synth - it simply opens at a URL instead of loading into a DAW.
For synthesis, the engine quality is comparable: the same oscillator and filter maths runs in native browser code. The real difference is ecosystem - you cannot load third-party plugins, and you are limited to the instruments the platform ships. For writing, sketching and sound design that is rarely the limit; for a mix built around specific plugin chains, it is.
Yes. Web MIDI passes notes, velocity, pitch bend, mod wheel and control changes straight through, and a class-compliant USB or Bluetooth controller needs no driver. Chrome and Edge have the most complete support; Firefox works; Safari depends on the version.
Currently 6 distinct synth engines - Quantum Synthesizer X, Analog Synth, Wave Rider, Modern Piano and the Theremin - alongside the rest of the 20+ app catalog. They are separate engines, not presets of one instrument.
No. There is no installer, no plugin to scan, no licence file and no driver. A current version of Chrome, Edge, Firefox or Safari is the entire requirement.
Yes - the full instruments export WAV, and patterns and sequences export MIDI, so a sketch made in the browser can be finished anywhere. The playable brick on this page is a demo and does not record.
The category page the catalog never had. What a browser synth is, how wavetables work, how an 808 is built, and what you give up by leaving the plugin folder behind.
The technique, not the product: what a wavetable is and why sweeping through one moves.
Read it → GuideA sine, a pitch envelope and a glide - the whole 808 recipe, on a grid you can play.
Read it → GuideWhere a browser synth replaces a plugin, and the three cases where it plainly does not.
Read it →All 6 synths, plus the drum machines, samplers and effects, on one €9.90/month subscription. Seven days free with everything unlocked, and no card to start.
Already subscribed? Launch Quantum Synthesizer X →