Question 1

What is Synths.pw?

Accepted Answer

Synths.pw is the home of Webrack, a real modular synthesizer that runs in your web browser. You drag modules into an empty rack, connect them with virtual patch cables, and turn knobs to shape sound in real time. The module library is curated rather than exhaustive, covering oscillators, filters, envelopes, sequencers, samplers, drum voices, effects, and native ports of legendary Eurorack modules like Mutable Instruments Plaits, Rings, Clouds, Elements, and Warps. The site also hosts the Academy: free interactive courses on sound synthesis where each step pairs a short prose explanation with a custom hands-on widget and a real Webrack rack. Free forever, no install, no account required to play.

Question 2

Is Synths.pw free?

Accepted Answer

Yes. Webrack is free forever. All Academy courses are free, including Eurorack 101 and Additive Synthesis. You can use the synth and play through every lesson without an account. Signing in with email, Google, or GitHub costs nothing and unlocks saving and sharing your own patches with permanent URLs you can drop into Reddit, Discord, KVR, or anywhere else.

Question 3

Do I need to install anything to use Synths.pw?

Accepted Answer

No. Everything runs in your web browser using the Web Audio API and a high-performance audio worklet. There is nothing to download, install, or configure. A modern desktop browser (Chrome, Edge, Firefox, Safari) gives the best experience because the synth uses SharedArrayBuffer for low-latency audio. You can also run it on iPad or modern phones. The first time you load Webrack the engine compiles its WebAssembly modules in a few hundred milliseconds; after that it is instant.

Question 4

What is modular synthesis?

Accepted Answer

Modular synthesis is a way of building sound by combining small specialised modules (oscillators, filters, envelopes, sequencers, effects) and patching cables between them. Unlike a fixed-architecture synth, a modular synth has no preset signal flow: the cables you draw decide whether the LFO modulates pitch, filter cutoff, or amplitude, and you can rewire the patch at any time. The Eurorack format is the most popular hardware standard, but modular synthesis is older than the format itself and works equally well in software. Webrack reproduces the Eurorack signal model end-to-end, including 1 V/octave pitch tracking and the same cable-as-signal abstraction.

Question 5

What is Eurorack?

Accepted Answer

Eurorack is the dominant hardware modular synthesis format, defined by Doepfer in 1996. Modules are 128.5 mm tall, measured in units of HP (one HP equals 5.08 mm of width), and powered by a shared bus board. Signals on Eurorack run at +/- 5 V audio level and 0–8 V control voltage, with pitch tracking standardised at 1 V per octave. Tens of thousands of modules from hundreds of makers use the same cables, jacks, and conventions, so any module patches with any other. Webrack follows the same standard so the skills you learn here transfer directly to a real Eurorack rig.

Question 6

What is a VCO?

Accepted Answer

A VCO is a Voltage Controlled Oscillator: the module that generates raw tone in a synth. The pitch is set by a control voltage on its V/Oct input (one volt per octave), and most VCOs offer multiple simultaneous waveform outputs, typically sine, triangle, sawtooth, and square. The waveshape determines the harmonic content and therefore the timbre: a sine has only the fundamental, a sawtooth has every harmonic falling at 1/n, a square has only odd harmonics. In Webrack the VCO is the first module taught in Eurorack 101, and it is the heart of every classic synthesizer voice.

Question 7

What is CV in synthesis?

Accepted Answer

CV stands for Control Voltage: a slow-moving voltage signal that one module sends to another to control a parameter, like an envelope opening a VCA, an LFO sweeping a filter cutoff, or a sequencer driving an oscillator's pitch. In modular synthesis audio and CV use the same cables, jacks, and voltage range — only the speed differs. A signal cycling 440 times per second is audio you hear; the same signal cycling once per second is a CV that turns knobs for you. Pitch CV is standardised at 1 V per octave, gate and trigger CVs are 0/+5 V pulses, and most other CVs are bipolar +/- 5 V.

Question 8

What is additive synthesis?

Accepted Answer

Additive synthesis builds complex sounds by summing many simple sine waves at different frequencies, amplitudes, and phases. It is based on Fourier's theorem, which proves that any periodic waveform can be decomposed into a sum of sine waves at integer-multiple frequencies of a fundamental. The Hammond B3 organ is purely additive: nine drawbars set the loudness of nine harmonics. Additive synthesis is uniquely powerful for inharmonic timbres like bells, gongs, and metal plates, where the partials sit at non-integer ratios and no filter sweep can reach. The Synths.pw Additive Synthesis course teaches the technique from first principles in 23 hands-on steps.

Question 9

Do I need to know anything about synths to start?

Accepted Answer

No. Both Academy courses are designed for absolute beginners. Eurorack 101 starts with the question what a module is and walks you to a fully patched modular voice in 20 short steps. Additive Synthesis starts from a single sine wave and builds Fourier's theorem into your ear over 23 steps. Each step is interactive: you read a paragraph, twist a knob or patch a cable, and hear what changed. There is no theory you have to study before opening the first lesson, and no expensive hardware to buy. If you can use a web browser, you can take the courses.

Question 10

What can I learn in the Academy?

Accepted Answer

Two free interactive courses are live today. Eurorack 101 introduces modular synthesis from the ground up: what a module is, audio versus CV, 1 V/octave pitch, gates, triggers, envelopes, filters, mixers, sequencing, and reverb, ending with a complete patched voice you can keep tweaking. Additive Synthesis builds complex sounds from pure sine waves using Fourier's theorem, covering harmonics, phase interference, formants, Hammond drawbars, inharmonic bells, per-partial decay, and a 2D sound sculpture capstone. Every lesson is interactive: you read, twist a knob, and hear what changed alongside a real Webrack rack.