How does a synthesizer work?

A synthesizer builds sound from nothing but electricity: oscillators hum, a filter carves, an envelope shapes every note. A classic synth has three main parts in a row. Oscillators make a buzzing wave, a filter shapes its tone, and an amplifier sets how loud it is.

Read how it works: How does a synthesizer work? · The history of the synthesizer · More boxes on Glassbox

Chapters in this interactive model

1. Inside a synthesizer: Oscillators make a tone, a filter shapes it, an amplifier opens and closes. Keys tell them when.
2. Waves and harmonics: Every tone is a stack of pure sine waves. The stack sets the sound.
3. Carving the sound: the filter: Start bright, then take harmonics away. That is subtractive synthesis.
4. Attack, decay, sustain, release: Every note has a shape in time. Four numbers set it.
5. FM: one wave wobbles another: Two plain sine waves can make bells, brass and electric pianos.
6. MIDI, sequencers and drum machines: Three bytes say “play this note”. A sequencer sends them on time, over and over.