The Analog Modular Simulator is a free virtual modular synth: drag oscillators, filters, envelopes and sequencers into a virtual Eurorack, patch them together and hear control voltage at work – a hands-on way to learn modular synthesis in your browser, on desktop, tablet and phone.
Features
01 / 17 · Sound sources
Voltage-controlled oscillator with sine, triangle, sawtooth and square at the same time. The waveforms are band-limited and stay largely free of aliasing even in high registers. Pitch follows 1 V per octave, with fine tuning, pulse width with a PWM input, frequency modulation and hard sync.
02 / 17 · Sound sources
Noise generator with three outputs for white, pink and brown noise. White noise suits hiss and hi-hats, pink noise wind and surf, brown noise a deep rumble. Combined with a filter, it provides percussion, ambience and random modulation.
03 / 17 · Filters
Multimode filter with simultaneous low-pass, band-pass and high-pass outputs. Cutoff and resonance shape the sound; at high resonance the filter self-oscillates. Drive adds analog saturation. A CV input with adjustable depth and a V/Oct input control the cutoff.
04 / 17 · Filters
CMOS multimode filter with a rough, distorted character: low-pass, band-pass, high-pass and notch at four simultaneous outputs. The resonance sounds raw and stays limited even at its maximum setting. BITE overdrives the CMOS stage; the red LED indicates the amount of distortion.
05 / 17 · Amplifiers & mixers
Two voltage-controlled amplifiers in one module. An envelope at the CV input turns a sustained tone into a played note. A switch selects a linear or exponential response.
06 / 17 · Amplifiers & mixers
Four-channel mixer with a level control per channel and a master control. It combines oscillators, noise or effect paths and mixes control voltages as well as audio signals.
07 / 17 · Amplifiers & mixers
Ring modulator: it multiplies two signals and produces metallic, bell-like tones. The DIODE knob blends from ideal multiplication to the behaviour of an analog diode circuit.
08 / 17 · Effects
Granular texture processor: it records the input continuously and plays back short grains from it – each with its own pitch, size and window shape, evenly, at random or triggered in time. FREEZE holds the current buffer; feedback and a plate reverb produce pads, textures and echoes.
09 / 17 · Modulation
Low-frequency oscillator for modulation: sine, triangle, sawtooth and square from 0.01 to 50 Hz, bipolar or unipolar. The rate is voltage-controlled, and a reset input restarts the phase.
10 / 17 · Modulation
Envelope generator for the time course of a note: attack, decay, sustain and release with exponential curves as in analog circuits. It is triggered by a gate and has a retrigger input and an inverted output.
11 / 17 · Modulation
Function generator and analog computer for voltages: two channels rise and fall with their own times and curve shapes, from logarithmic to hyper-exponential. They serve as envelope, LFO, portamento or, at audio rate, as an oscillator. Two offset channels and a bus that adds, inverts and selects the highest voltage complete the module.
12 / 17 · Clock & sequencing
Master clock of the rack: 20 to 300 BPM, six outputs from four times to one eighth of the tempo, run/stop and reset. Sequencers, envelopes and LFOs run in sync with it.
13 / 17 · Clock & sequencing
8-step sequencer with a pitch knob and a gate button per step. Length, voltage range, semitone quantization and glide are adjustable – for melodies and basslines. The clock advances the steps.
14 / 17 · Input & output
Keyboard interface for the computer keyboard, the mini keyboard and MIDI keyboards. It outputs pitch, gate, velocity and trigger; octave and glide are set directly on the module.
15 / 17 · Input & output
Two-channel oscilloscope that displays waveforms, envelopes and modulation in real time. Time base and sensitivity are adjustable; triggering on channel A keeps periodic signals steady on screen.
16 / 17 · Input & output
Recorder for mono and stereo recordings, started by button or in time via the trigger input. It saves WAV files in 16-bit, 24-bit or 32-bit float; level meters and recording time are shown on the module.
17 / 17 · Input & output
Audio input for a microphone, guitar or audio interface. The signal is available as audio, as an envelope and as a gate, which opens once the level exceeds the threshold. An input signal can thus control a filter, start an envelope or advance the sequencer. Any number of Input modules share one input, each with its own channel and gain.
FAQ
A free modular synthesizer that runs entirely in your browser: a virtual Eurorack with oscillators, filters, envelopes, a sequencer, a granular effect and more, which you connect with patch cables. Sound is generated by a dedicated WebAssembly audio engine right on your device. Developed by Elias Ritter.
Yes. The Analog Modular Simulator is free, needs no sign-up and shows no ads.
No. The simulator starts right in your browser and also works offline after your first visit. If your browser offers it, you can additionally set it up as an app via “File → Install app”.
Yes. The interface adapts to small screens and can be fully operated by touch – on Android phones, iPhone and iPad as well as on Chromebooks. A tablet in landscape orientation is the most comfortable.
Current versions of Chrome, Edge, Firefox and Safari – on computers, tablets and phones. JavaScript, WebAssembly and Web Audio are required; MIDI keyboards work in Chrome, Edge and Firefox.
Yes. You learn the basics without spending money on hardware: patch oscillator, filter, amplifier and envelope into a classic subtractive synth voice, understand control voltages and gates, and build melodies with clock and sequencer. Ready-made demos – from a first synth voice to an acid bassline – show how it works and are yours to change.
A modular synthesizer consists of separate modules that you connect yourself with patch cables. An oscillator (VCO) generates the tone, a filter (VCF) shapes the timbre, an amplifier (VCA) controls the volume. Envelopes, LFOs and sequencers provide control voltages that move these parameters – turning a sustained tone into a played note or a melody. The demo “First voice” in the “Demos” menu shows exactly this chain.
Eurorack is the most widespread format for modular synthesizers: standardized modules, whose width is measured in HP, sit in a case and are connected with patch cables. Signals are voltages – audio, control voltages, gates and triggers. The Analog Modular Simulator recreates this principle in your browser, with a rack, rows, module widths and the usual voltage ranges.
CV (control voltage) is a voltage that controls a parameter – such as pitch at 1 V per octave or the cutoff frequency of a filter. A gate is an on/off signal (0 or 10 V) that tells how long a note lasts; a trigger is a short pulse that starts something. In the simulator, the tooltip on every plug shows which kind of signal runs through the cable.
Yes. Add the Keys / MIDI module and turn on “Enable Web MIDI” under “File → Options → Input devices”. Chrome and Edge support Web MIDI directly, Firefox after you grant permission, Safari currently not at all.
Yes, with the Input module: press ON and allow microphone access; choose the input device under “File → Options → Audio”. The signal is then available in the rack as audio, envelope and gate – for an auto-wah, for example, or to step the sequencer with your voice. Use headphones, otherwise it feeds back.
Yes. The Recorder module records in mono or stereo – by button or in time via its trigger input – and saves the take as a WAV file in 16-bit, 24-bit or 32-bit float.
Only on your device: the current state is kept automatically in your browser’s storage. Use “File → Save” to download it as an .ams.json file and open it again on any device.
Yes. You write custom modules in a small script language as a text file ending in .amsmod – several modules can share one file. In the simulator, open it via “File → Load custom modules …”: every module shows a preview, and “Add” puts it into the rack. Custom modules are saved and shared with the patch. The script language guide explains every function, shows examples and offers an AGENTS.md that lets AI assistants write working modules.