How synths & drum machines work

Strip away the panel graphics and almost every synthesizer does three jobs. A source makes a raw, buzzy tone (the oscillator). A shaper carves that tone — a filter removes frequencies, an amplifier sets loudness. A mover changes those settings over time — envelopes and LFOs turn a static beep into something that plucks, swells or wobbles.

Learn to see those three jobs and any synth becomes readable, whether it has four knobs or four hundred menu pages.

Analog synths generate and shape sound with continuous voltages flowing through circuits. Tiny imperfections — drift, warmth, saturation — are part of the character. Digital synths calculate the sound as numbers. That makes things possible that circuits struggle with: wavetables, FM, huge modulation matrices, perfect recall.

Many instruments mix the two. The Oxford OSCar used digitally-generated waveforms through an analog filter back in 1983. The Hydrasynth is fully digital but designed to be played with the immediacy of an analog panel.

A drum machine is a set of small, single-purpose synth voices — a kick is a sine wave that drops in pitch, a hi-hat is filtered noise — plus a step sequencer that triggers them on a grid. The TR-808 built its voices from analog circuits; later machines added samples.

The grid is usually 16 steps per bar: each step is a sixteenth note. Learn to count it and you can read any pattern on any machine.