Online synthesizer: learn by shaping a sound
Build a sound one step at a time with this online synthesizer. Choose the oscillator waveform, remove some of its upper harmonics with a low-pass filter, then shape the volume of a note with the ADSR envelope. Start with Bright, Soft or Short and percussive, and change one control while listening.
How to use it
- Choose Bright, keep the volume modest and hold a keyboard note. You can also select Play a note for a short example.
- Compare the four waveforms. Sine is smooth; sawtooth and square give the filter more harmonics to work with.
- Hold a note and lower Filter cutoff. Turn resonance up gradually to hear the region around the cutoff become more prominent.
- Adjust A, D, S and R, look at the envelope and play again. Attack, decay and release are measured in seconds. Sustain is a level, not a time.
- Use the octave arrows to move the keyboard. Z S X D C V G B H N J M cover twelve chromatic notes; Q starts the next octave.
Help and explanations
You can play using touch, a mouse or a computer keyboard. The envelope diagram follows your settings, while the smaller display draws the actual output waveform. Audio is generated in the browser; there is no microphone request, account or sample library to download. Your last sound settings are kept on this device.
Hear the four envelope stages
Attack sets the rise from silence to the initial peak. Decay takes the sound from that peak to its sustain level. Sustain stays in place while the key is held. Release begins when you let go.
For a slow, soft entrance, try an attack near 0.3 seconds. A release near 0.8 seconds lets the note fade after your finger moves away. Compare that with the Short and percussive starting sound: a quick attack, falling level and short release make the same keyboard feel quite different.
Why the filter changes some waves more than others
A low-pass filter reduces frequencies above its cutoff. A sawtooth contains many harmonics, so lowering the cutoff removes much of its brightness. A sine wave has a simpler spectrum: filtering it may mainly make it quieter.
Resonance emphasizes the area near the cutoff. Compare sounds at a sensible volume, since that emphasis can also change perceived loudness. The Lalatone spectrum analyzer is useful for exploring individual frequencies.
How this instrument makes its sound
Each note uses an oscillator, a low-pass filter and a gain envelope through the browser interfaces defined in the W3C Web Audio specification. The envelope graphic explains the stages, and the waveform display observes the real output. This learning instrument provides synthesis controls and a keyboard; it does not include a sequencer or audio export.
Tips
- Compare one setting at a time while playing the same note.
- Set sustain to zero to make a note fade even while its key is still held.
- Stop or Esc silences the instrument. Switching to another tab also stops held notes.
Frequently asked questions
Can I use the synthesizer on a phone?
Yes. Play its keys with your fingers. Small screens show fewer notes at once; the arrows let you move to other octaves.
What does ADSR mean?
Attack, decay, sustain and release: the four stages used here to shape the volume of a note.
Does this tool use my microphone?
No. It generates audio and does not listen to your room.
Can I export a performance?
This tool focuses on learning synthesis. For a virtual instrument with MIDI and WAV export, try the Lalatone piano.