Free Online Keyboard Synthesizer

The oscillator is where a synth's sound is born. It vibrates the air at the note's pitch, and the waveform decides the tone color:

• Sine — a pure, hollow whistle (tuning fork)
• Triangle — sine with a soft edge, flute-like
• Square — hollow and reedy, the chiptune sound
• Sawtooth — bright and buzzy, the synth classic

Same note, four outfits. The letter printed on each piano key plays it — hold Z (middle C in the default range) and switch waveforms while it rings.

Square waves only contain odd harmonics, which is why they sound hollow; sawtooth has every harmonic, which is why it cuts through a mix.

A lowpass filter lets low frequencies through and removes everything above its cutoff point, like a hand muting guitar strings.

• Cutoff high → bright, open sound
• Cutoff low → dark, underwater sound
• Resonance boosts the frequencies right at the cutoff — the whistling "wow" of acid basslines

Bass presets keep the cutoff low so the low end stays fat. Take the Brightness knob (filter cutoff) for a spin: start around 640 Hz, choose Lower, then hold Z, and slowly turn it up to hear the sound open.

The ADSR envelope shapes how loud a note is over its life:

• Attack — how fast the note arrives
• Decay — the first dip after the peak
• Sustain — the level while you hold the key
• Release — the fade after you let go

Short attack + low sustain = pluck. Long attack = strings and pads. Nothing proves it like hearing it: push the Attack slider to about 0.35 s, then hold a chord with Space for sustain — the notes now swell in like a string section.

Reverb fakes a room: thousands of tiny reflections smearing the sound. A little glues a patch together; a lot puts it in a cathedral.

Delay is a distinct echo — the note repeats in time, instantly making simple melodies sound composed.

• Reverb = size and distance
• Delay = rhythm and movement

Pads are where space effects shine. Turn Reverb up to about 60% and hold a wide chord — the tail should hang in the air after you release the keys.

Layer two oscillators on the same note and nudge one a few cents out of tune. They drift against each other, creating a shimmering beating — and the sound doubles in size.

• That drifting interference is called chorusing
• Stack 7 detuned saws and you get the 90s trance super saw

The Super Saw preset already runs two detuned saws. Load it, hold a chord, then raise the Brightness knob slowly — that opening sweep is the sound of a thousand festival anthems.