Virtual Synthesizer — Play Online
Shape sounds from scratch — choose a waveform, sculpt the envelope, dial the filter, and add LFO modulation. Play on a two-octave keyboard, load a preset, and export your performance as a WAV file. No download needed.
💻 A S D F G H J K L ; ' Z X C = white keys | W E T Y U O P = black keys | Octave via − + buttons
🎵 Audio Export
Record your performance directly to audio — no video. Opens in any DAW or audio app.
Ready.
🎬 Screen Recording
Record video of your session and download as WebM.
Ready.
✅ How to Use
- Pick a Preset to start with a ready-made sound, or build your own from scratch.
- Choose an oscillator waveform — sine is smooth and pure, square is hollow, sawtooth is rich and buzzy, triangle is soft.
- Shape the ADSR envelope: Attack controls how fast the note fades in; Decay is the initial drop; Sustain is the held level; Release is the tail after you let go.
- Use the Filter to sculpt tone. Drag Cutoff down for a warm, muffled sound. Raise Resonance for a sharp peak at the cutoff frequency.
- Add LFO modulation to pitch (vibrato), filter (wah/sweep), or amplitude (tremolo).
- Play the keyboard by clicking keys or using keyboard shortcuts. A S D F G H J K L ; ' Z X C = white keys, W E T Y U O P = black keys. Hold multiple keys for chords. Use the − + buttons to shift octave.
- Hit ⏺ Record then play — press Stop and download your performance as a .webm file.
🎛️ Preset Reference
Each preset is a named starting point. You can tweak any parameter after loading one.
| Preset | Wave | Character | Good for |
|---|---|---|---|
| Warm Pad | Sine | Slow attack, long sustain, open filter | Ambient chords, backgrounds |
| Saw Lead | Sawtooth | Fast attack, bright filter, slight LFO | Melodies, classic synth leads |
| Bass | Sine | Low octave, fast decay, closed filter | Sub-bass lines |
| Pluck | Sawtooth | Very fast decay, no sustain | Arpeggios, staccato |
| Strings | Sawtooth | Slow attack, mid filter, vibrato LFO | String-like pads and swells |
| Organ | Square | Instant on/off, no envelope | Hammond-style organ lines |
| Wobble | Sawtooth | LFO on filter at slow rate | Dubstep, electronic bass |
| Bell | Sine | Fast attack, long decay, high filter | Bell tones, marimba-like |
| Flute | Triangle | Soft attack, gentle vibrato | Melodic, breathy tones |
| Clean | Sine | Neutral — all defaults | Starting point for sound design |
About Synthesis
A synthesizer generates sound electronically rather than acoustically. Unlike a piano (which strikes strings) or a guitar (which vibrates strings), a synthesizer creates sound from electrical oscillations — waveforms that repeat at a specific frequency. By shaping and combining these waveforms, you can recreate almost any sound imaginable, or invent entirely new ones.
This synthesizer uses subtractive synthesis — the most common method, used in classic instruments like the Moog Minimoog, Roland Juno, and Korg MS-20. You start with a harmonically rich waveform (sawtooth or square) and subtract frequencies using a filter. The ADSR envelope then shapes how the volume changes over time, giving the sound its characteristic feel.
Everything here runs in real time via the Web Audio API — no plugins, no samples, no server. Each note is generated as a live oscillator in your browser's audio engine.
Frequently Asked Questions
What does each waveform sound like?
Sine is smooth and pure — just the fundamental frequency, no overtones. Square is hollow and woody, like a clarinet. Sawtooth is bright and buzzy — the richest in harmonics, closest to a violin or brass. Triangle is between sine and square — soft but with a hint of edge.
What is ADSR?
ADSR stands for Attack, Decay, Sustain, Release — the four stages of how a note's volume behaves. Attack is how long it takes to reach full volume after a key press. Decay is the drop from peak to the sustained level. Sustain is the volume held while the key is held. Release is how long it takes to fade after the key is released.
What does the filter cutoff do?
A lowpass filter removes frequencies above the cutoff point. At maximum cutoff, the full bright waveform passes through. As you lower the cutoff, high frequencies are progressively removed, making the sound warmer and more muffled. Resonance boosts the frequencies right at the cutoff point, creating the characteristic "synth sweep" sound.
What is an LFO?
LFO stands for Low Frequency Oscillator. It oscillates too slowly to be heard as a pitch, but its output is used to modulate other parameters. LFO on pitch creates vibrato (like a singer wavering slightly on a note). LFO on filter creates a wah sweep. LFO on amplitude creates tremolo (volume wobble).
How does WAV export work?
When you press Record, the synth connects your audio output to a MediaRecorder capturing raw audio. When you press Stop, the captured audio is assembled into a standard .wav file and offered for download. The file contains only audio — no video — and opens directly in GarageBand, Logic, Ableton, Audacity, or any audio app.
Can I play chords?
Yes — hold multiple keyboard keys simultaneously. Each key triggers an independent oscillator with its own envelope. You can sustain up to 8 simultaneous notes.
📚 References & Notes
- •Synthesis method: subtractive synthesis — oscillator → filter → amplifier (VCO→VCF→VCA)
- •WAV export uses MediaRecorder API on a dedicated AudioContext destination stream
- •Reverb: convolution reverb with synthetic impulse response (1.5s decay)
- •Tuning: A4 = 440 Hz, equal temperament
- •Classic reference: Moog, R. A. (1965). A voltage-controlled low-pass high-pass filter for audio signal processing.