# Free Online Synth — Play a Virtual Synthesizer | Resonant > Play a free 37-key virtual synthesizer in 3D with sampled sawtooth lead sounds. Shape touch dynamics, hold notes, or glide across the keys. Canonical page: https://resonant-appsoverflow.web.app/instruments/synth/ Creator: AppsOverFlow Guide updated: 2026-10-12 Find a hook across 37 playable 3D keys from C3 to C6. Classic view keeps the two-octave C4–B5 keyboard. Soft, Natural and Bold change the strength and brightness of each new note. ## How to play In 3D view, choose Play to tap, strum, or glide across a playing surface. Hold keys or wind surfaces to sustain a note. Choose Rotate to inspect the model; scroll or pinch to zoom. Use the labeled note controls or computer keys for chords and the full range. Classic view provides the original illustrated playing surface. Hold a note using touch, mouse, or a computer key. The illustrated knobs are decorative; adjust Instrument volume in Playing preferences below the instrument. Full screen also includes a sound toggle. ## Sound A sampled sawtooth lead supplies the electronic voice, with a soft release and a little room reverberation. ## Make a hook from short notes and a hold Repeat a small electronic motif with one deliberate long note. You can shape the phrase without relying on the decorative knobs. Starting tempo: 80 BPM. Use Keep the beat for a steady pulse. 1: C4 (Z) | 2: Release and rest | 3: E4 (C) | 4: G4 (B) | 5: C4 (Z) | 6: Keep holding C4 | 7: G4 (B) | 8: Release and rest 1. **Choose the playable controls.** Use the labeled notes or Z, C and B for C4, E4 and G4. Set Instrument volume in Playing preferences to a comfortable level. 2. **Keep the first note short.** At 80 BPM, release the opening Z before beat 2. Play C and B on beats 3 and 4, then hold the next Z through beats 5 and 6. 3. **Finish with space.** Play B on beat 7 and release before the final rest. Repeat only after that rest, so the end of one phrase does not crowd the next. **What to listen for:** The held second C4 should make the repeated motif feel different from its short opening. The illustrated knobs do not alter the sound. **Try next:** Change only the held note to A4 using N. Keep its two-beat duration and compare where the phrase seems to settle. ## How do I record the synth in Resonant? 1. **Choose your playing controls.** Choose Play in 3D view or switch to Classic. Tap a playing surface, use the labeled note controls, or press a computer-key shortcut to enable sound. 2. **Record your idea.** Press Record above the instrument, then play your phrase. This records studio audio without using your microphone. Each take can last up to five minutes. 3. **Listen and keep a copy.** Press Stop, open Recordings, and listen to the take. Choose Download WAV or Original audio to keep a file. Saved takes stay on this device; clearing browser storage removes them. ## Questions and answers ### How do I play the online synth? In 3D view, choose Play to tap, strum, or glide across a playing surface. Hold keys or wind surfaces to sustain a note. Choose Rotate to inspect the model; scroll or pinch to zoom. Use the labeled note controls or computer keys for chords and the full range. Classic view provides the original illustrated playing surface. Hold a note using touch, mouse, or a computer key. The illustrated knobs are decorative; adjust Instrument volume in Playing preferences below the instrument. Full screen also includes a sound toggle. ### What sounds does the virtual synth use? A sampled sawtooth lead supplies the electronic voice, with a soft release and a little room reverberation. ### Can I adjust the synth knobs? The illustrated knobs are decorative. Use Instrument volume in Playing preferences to change the output level or set it to zero. Full screen also includes a sound toggle. ### How do I make a synth melody? Start with Z, X, and C for C4, D4, and E4. 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