A field guide to sound

Free explainers on audio, synthesis, DSP and theory, each built around a working figure you can operate and hear.

Open the synthesis figure

The synthesis figure: FM anatomy scene with modulator, index, carrier and output modules and their waveforms

Music Theory

Scales, modes, chords, progressions and tempo. 5 articles.

Scales explained beginner
Modes explained beginner
Chords and how they are built beginner
Chord progressions beginner
Tempo, time signatures and note timing beginner

The chord figure: an isometric electric piano with the keys of a C major chord pressed down

Audio Engineering

Signal flow, gain staging, acoustics and recording. 2 articles.

Signal flow basics beginner
Gain staging and headroom intermediate

DSP

Sampling, filters, FFT and how plugins actually work. 3 articles.

Sampling, Nyquist and aliasing intermediate
Synthesis Types beginner
How a compressor works intermediate

The compressor figure: an isometric bench drawing a transfer curve with threshold and ratio controls

Mixing

EQ, compression, space, balance and translation. 1 article.

EQ basics beginner

Genres

Tempo, harmony, rhythm and sound design by style. 1 article.

Anatomy of synthwave beginner

The synthwave figure: an isometric production console lifted into six layers

Instruments Interactive tools you can play with. Each one pairs with an explainer.

Why a field guide

ZX Audio Info is written for anyone who wants to understand sound, from a first lesson in scales to the maths inside a compressor. Every article sits in one of five chapters, each with its own colour, so you always know where you are. The best ones are built around a working figure: the real system drawn as an object you can turn, scrub and listen to, so cause and effect happen in front of you. It is free, it needs no account, and it is meant to stay open as a reference while you work. Start with six ways to make a sound.