🎛 Music Apps

Synthesizer

A subtractive synth with two oscillators, a resonant filter and two envelopes — playable from your keyboard.

Oscillators

Filter

Opens to 5000 Hz at the peak of the envelope.

Vibrato & level

0 notes sounding

Amplitude envelope

Filter envelope

Play with the mouse, or the A–; row for white keys and W E T Y U for black keys. Notes are polyphonic.

Overview

Synthesizer: subtractive synthesis you can actually see

This is a subtractive synthesizer — the architecture behind most of the classic analogue instruments. Two oscillators generate a harmonically rich waveform, a resonant low-pass filter removes part of that harmonic content, and two envelopes shape how the volume and the filter change over the life of each note. Almost every synth sound you have ever heard is some arrangement of those pieces.

The reason it is worth learning on something visual is that the controls are not arbitrary. Each one corresponds to a specific stage of the signal path, and the envelope graphs redraw as you move the sliders, so the relationship between a number and a sound stops being abstract. Six presets show genuinely different corners of the parameter space — a bass, a pad, a pluck, a lead, a bell and a drone — and every one is reachable from the others by moving sliders.

100% freeNo downloadPolyphonicWorks offline
How to use it
  1. 1Press a preset to hear a finished sound, then play the keyboard with your mouse or computer keys.
  2. 2Move the filter cutoff while playing — it is the single most expressive control on the instrument.
  3. 3Shape the attack and release in the amplitude envelope to turn a pluck into a pad.
  4. 4Detune oscillator B by a few cents for thickness, or by 1200 for an octave.
Key features
  • Two oscillators with four waveforms each, variable mix and detune from −1200 to +1200 cents
  • Resonant low-pass filter with its own envelope that opens and closes the cutoff
  • Separate ADSR envelopes for amplitude and filter, drawn live as you adjust them
  • Vibrato with adjustable depth and rate
  • Fully polyphonic — hold as many notes as your keyboard allows
  • Six presets spanning bass, pad, pluck, lead, bell and drone

Frequently asked questions

What does subtractive synthesis mean?
You start with a harmonically rich waveform — a sawtooth contains every harmonic — and subtract parts of it with a filter. It is sculpting rather than building, which is the opposite of additive synthesis where you stack simple sine waves together to construct a tone.
What do attack, decay, sustain and release do?
They describe how a note changes over time. Attack is how long it takes to reach full volume, decay how long it takes to fall to the sustain level, sustain is the level it holds while the key is down, and release is how long it takes to fade after you let go. A short attack and zero sustain gives a pluck; a long attack and high sustain gives a pad.
Why does the filter have its own envelope?
Because real instruments get brighter when struck and darker as they ring out. A filter envelope that opens quickly and closes as the note decays reproduces that, and it is the difference between a sound that feels alive and one that feels static.
Why can I only hold a few keys at once?
That is your computer keyboard, not the synth. Most non-gaming keyboards can only register a limited number of simultaneous keypresses. Playing with the mouse or a MIDI controller has no such limit.
📖

Full guide

Subtractive Synthesis Explained: Oscillators, Filters and Envelopes

How the classic synth signal path works, what each control really changes, and how to build a sound from scratch.

Oscillators & waveformsFilters and resonanceADSR envelopes

Related Articles & Guides

ArticleSubtractive Synthesis Explained: Oscillators, Filters and EnvelopesHow the classic synth signal path works, what each control actually changes about the sound, and how to build a patch from scratch.ArticleHow Vocal Removal Works: Phase Cancellation, Stereo Fields and Its LimitsWhy subtracting one stereo channel from the other removes a centred vocal, what makes some songs separate far better, and where AI models differ.ArticlePiano Tiles Strategy: Reaction Time, Rhythm and Scoring HigherWhy rhythm beats raw reflexes, how fast human reaction really is, the mistakes that end most runs, and drills that genuinely raise your score.