HitJam
Online Synthesizer
A synthesizer you play and shape in the browser. Pick a sound to start from, then move the wave, the filter and the envelope and hear it change under your fingers. Free, no download, no account.
Slow Pad
Slow, glowing chords that fill a room.
No MIDI keyboard? Play with your computer keys: bottom rows are the lower octave, top rows the higher one. Hold Shift to sustain. â â octave, â â semitone.
The controls
Wave
The raw shape the sound starts as, before anything is done to it.
Filter
Cutoff takes the brightness off the top. Resonance makes the frequency right at the cutoff ring, which is the classic synth âwahâ. Sweep is how far the cutoff opens by itself each time you press a key: turn it down to nothing and Cutoff alone decides how bright the sound is.
Envelope
How the loudness moves across one note: how fast it arrives, how it falls, where it settles while you hold, and how long it takes to go once you let go.
Nothing here is saved and nothing is uploaded. Reload the page and every control is back where it started.
What a synthesizer actually is
A synthesizer builds sound instead of recording it. There is no tape and no sampled instrument inside: an oscillator makes a raw tone, a filter removes part of it, and an envelope decides how that tone behaves across a single note. Change any of the three and you have a different instrument.
That is why a synth can sound like a bell, a bass and a pad without changing anything physical. The three controls above are the same three every hardware synth has had since the 1960s, under different names.
Start from a sound, then ruin it
Every preset on this page is a sound that ships on HitJam, and each one is a normal recipe rather than a locked patch. Load one, then pull the cutoff down and the brightest sound on the list goes muffled; push the attack up and a sharp pluck turns into a slow pad. The fastest way to learn what a control does is to take it to both extremes on a sound you already know.
Play it with your computer keys
The bottom row of letters is the lower octave and the top row is the higher one. Shift holds notes on, like the sustain pedal on a piano, and the arrow keys move the whole keyboard up and down. Nothing needs configuring.
A MIDI keyboard is better, because it sends how hard you hit each key and the synth answers it. Plug one in with a USB cable in Chrome, Edge or Firefox and allow MIDI once. If it does not show up, the MIDI keyboard test will tell you whether the computer is hearing it at all.
Sounds to try next
Every sound on the site is on a page of its own, with its own artwork and its own controls.
- Slow Pad, a soft wash that arrives late and leaves slowly
- Gameboy, square waves and the sound of a handheld console
- Bali Cave, struck metal with a long tail
- Prayers, a breathy choir-like pad
- Growler, a resonant bass with a filter that opens as you play
- Grand Piano, the opposite of all of these: a real instrument, recorded note by note
Questions people ask
- Is this a real synthesizer?
- Yes. The sound is built from oscillators, a filter and envelopes, calculated as you play rather than played back from a recording. That is what makes a synthesizer a synthesizer, and it is the same engine the rest of the site runs on.
- Do I need to install anything?
- No. It runs in the browser on the computer or phone you are reading this on. There is no plugin, no account and no download, and nothing you play is uploaded anywhere.
- Can I use my MIDI keyboard?
- Yes, in Chrome, Edge or Firefox on a computer. Plug the keyboard in with a USB cable, allow MIDI once when the browser asks, and your own keys play the synth with real velocity. Safari has no MIDI support on any device.
- What do the controls actually do?
- Wave picks the raw shape the sound starts as. Cutoff takes brightness off the top and resonance makes the frequency at the cutoff ring. The four envelope controls shape the loudness of one note: how fast it arrives, how it falls, where it sits while held, and how long it takes to fade once you let go.
- Can I save a sound I like?
- Not yet. Reload the page and every control is back where it started. Saving would need an account, and this page deliberately does not have one.
- Is it free?
- Yes, and there is no paid tier behind it. Nothing here is a trial of something else.
New to this? What is a virtual instrument? explains where a synthesizer sits next to a sampled instrument, in plain English.