Synthesizer
A polyphonic subtractive synthesizer in the browser — three oscillators with pulse-width modulation, noise and unison, a resonant 12 or 24 dB filter with its own envelope, two LFOs, glide and mono legato, distortion, chorus, delay and reverb, an arpeggiator, 26 original presets, and an "explain" mode that says what each section does. Play it on screen, from the computer keyboard or a MIDI keyboard.
Added
How to use it
Pick a preset and play, or start from Init and build a sound section by section. Turn on Explain to see what each part of the synth does as you change it.
How to use it
-
Play by clicking or touching the keyboard (lower on a key is louder), from the computer keyboard — the Z–M row and the Q–U row are two octaves, with the black keys on the rows above them; ← and → move an octave — or from a MIDI keyboard: Connect MIDI keyboard listens on every input and channel. Pitch bend is ±2 semitones, the mod wheel adds vibrato, the sustain pedal (CC 64) holds notes, and program changes pick presets.
-
Oscillators. Three, each with a waveform (saw, square, pulse, triangle, sine, and three drawn as Web Audio periodic waves: organ, hollow and vocal), octave, semitones, fine detune and level. A pulse oscillator is two band-limited saws, one delayed by width ÷ frequency and subtracted, so its width can be swept in real time by an LFO — that’s PWM. Unison stacks up to seven detuned copies of each oscillator across the stereo field.
-
Filter. Low-pass, high-pass, band-pass or notch, 12 or 24 dB per octave (one or two Web Audio biquads), with resonance, an envelope amount in octaves (positive or negative), key tracking and velocity.
-
Envelopes. Attack, decay, sustain and release for the filter and the amplitude. Attack is a straight ramp; decay and release are exponential, like an analogue envelope.
-
LFOs. Two, each to pitch (vibrato), cut-off (wah, sweeps), amplitude (tremolo) or pulse width.
-
Voice. Up to 16 notes at once (the oldest is stolen beyond that); Mono plays one at a time — hold a key and press another to slide to it without restarting the envelopes. Glide sets the slide time.
-
Effects. Distortion (a tanh wave-shaper), chorus (two modulated delays, panned), delay with feedback, and reverb from a generated impulse response.
-
Arpeggiator. Up, down, up-down, random or as-played over one to three octaves, at a tempo and note length you choose, with a gate length and latch.
-
Patches. 26 presets of my own — basses, leads, pads, plucks, keys, brass and effects. Save as… keeps your patch in this browser; Copy JSON and Paste JSON move patches between browsers; the Share link carries the current patch.
For sequencing, the MIDI monitor and step sequencer can drive this synth through a virtual MIDI port (IAC Driver on a Mac, loopMIDI on Windows). Related: SID sound designer (the Commodore 64’s chip), ProTracker MOD player, audio oscilloscope and spectrum analyser for looking at real signals, digital filter designer for the maths of filters, and room acoustics for notes and frequencies.
Feedback is a gift. Something to improve, a feature to add, or a bug? Tell me.
Runs entirely in your browser; nothing you type leaves this page.