Drums

Clap

A self-contained handclap voice: bandpass-filtered noise driven by a multi-burst envelope plus a soft reverb tail.

What is a Clap?

A clap voice synthesizes the sound of a handclap from filtered noise. There is no sample; there is no sine; there is no body in the kick-drum sense. There is just noise shaped by a very particular envelope, and the cleverness is entirely in the envelope.

If you stand in a room and clap once, the sound is roughly bandpass-filtered noise with a sharp transient and a fast decay. Easy enough to synthesize. But that does not sound like a 'clap' on a drum machine - it sounds like a single 'tsk'. The thing your ear actually recognizes as a clap is several claps in very quick succession, the way a crowd does it slightly out of phase, plus the room's reverberation washing out the tail. That perceptual fact is what the Roland TR-808 CP codified into a circuit.

The 808 clap topology is two parallel paths driven by the same noise source. The first path is a multi-burst envelope: three or four very short amplitude pulses spaced about 10 ms apart, each one a quick sawtooth-shaped attack-and-decay. That stack of bursts is what fools your ear into hearing 'multiple hands'. The second path is a smooth exponential decay - a longer, gentler tail that simulates the room. The two are mixed, and the result is the clap. Change the burst count for tight versus ragged, change the spread for slow versus snappy, change the tail mix for dry versus reverberant. That's the whole instrument.

Our Clap

Webrack's Clap keeps the multi-burst topology that defines the sound. White noise goes through a state-variable bandpass for tone shaping and is then sent through two parallel envelopes - the multi-burst body path and the smooth tail path - mixed by the Rev knob. Eight knobs, two inputs, two outputs.

Tone sets the bandpass center; Snap sets how many initial bursts (2-6); Spread sets the time between them (5-20 ms); Decay is the length of the reverb tail; Rev mixes burst-versus-tail; Color shifts the bandpass character; Drive adds tanh saturation on the way out. Push Snap up and Spread wider for messy, ragged claps; pull both down for tight techno claps.

It will not be a perfect 808 emulation - the original is an analog circuit and we are filtered noise plus envelopes - but the multi-burst-plus-tail topology that defines the clap sound is preserved exactly, and you get the full control surface in the browser with no install.

In a patch

A clap almost always lives on the backbeat - hits 2 and 4 of a 4/4 pattern, often layered with or in place of the snare. Patch a Clock divided down to those beats, or use a step sequencer with hits programmed on those positions, into the clap's trigger input. The clap typically gets its own channel in the mix because its tail is longer than a snare's and it benefits from independent EQ.

Two production techniques are worth knowing. Layer a clap on top of a Snare Drum to fatten the backbeat - the snare gives you body, the clap gives you the slap. And feed the clap a gate input from an Euclidean rhythm rather than a clock to get sparse, syncopated clap patterns that move around the bar. The reverb tail of a clap voice often does most of the room-feel work in a stripped-back techno or house mix.

Inputs

Trig (gate) — Trigger input. Each rising edge fires the clap. Edge-triggered (pulse width independent).
Acc (cv) — Accent CV, 0-10V. Boosts level for emphasized hits. Patch the AC2 output of Euclidean here for accented claps.

Outputs

Out (audio) — Audio output at Eurorack levels.
Env (cv) — Envelope follower of the clap's amplitude. Useful for ducking other voices to the clap or driving secondary modulation.

Controls

Tone — Bandpass filter center, 500-3000 Hz. Lower = duller body claps; higher = brighter, snappier claps.
Decay — Reverb-tail decay length, 50-500 ms. Short for tight techno; long for ambient washes.
Snap — Number of initial bursts, 2-6. More bursts = more ragged, more "human-multi-handed" sound. 3-4 is the classic setting.
Spread — Time between bursts, 5-20 ms. Tighter = single-clap feel; wider = audibly multi-handed.
Color — Noise highpass shaping, 0.5-4 kHz. Adjusts the underlying texture color before the bandpass.
Rev — Mix of the long decay tail under the burst section. 0 = dry slap; higher = roomier, snappier sustain.
Drive — Tanh saturation. Adds grit and squashes peaks for industrial-style claps.
Gain — Output level, 0-1. Trim to balance against the rest of the kit.

Inspired by

The 808 clap is famously not one clap - it's a stack of three or four very short noise bursts spaced ~10 ms apart, followed by a longer noise tail that mimics room reverb. We keep that same dual-envelope topology: a multi-burst sawtooth envelope drives the body, a smooth exponential decay drives the tail, and the two are mixed by ear. TypeScript DSP, 44.1 kHz, AudioWorklet.

Roland TR-808 CP
Roland TR-909 CP

← Back to all modules