krystopfer

An experiment by Christopher Fisher · Scotland

Polyrhythm
simulator.

See and hear different rhythms sharing the same cycle. Build up to twelve layers, each with one to twelve beats.

Play with rhythm ↓

Sound Lab / Rhythm

Time, in shape.

One cycle. Different divisions.
Hear where they meet.

Start with a groove

Four layers. Tempo and kit included. Sound stays under your control.

Inside the grooves

Genre-inspired studies built from evenly spaced hits. The djent examples explore five or seven against four; they do not reproduce asymmetric chug patterns or specific songs.

Metal drive
Driving kick, backbeat snare, eighth-note hats and a downbeat crash.
Half-time crush
Double-kick pulse with the snare on beat three.
Djent · five over four
Five even kick hits push against a four-beat cymbal pulse and backbeat.
Djent · seven over four
Seven kick hits against four ride hits, anchored by a half-time snare.
Cyberpunk big beat
Four-on-the-floor kick, snare and clap backbeats, and off-beat hats.
Doom stomp
Slow kick steps, a snare on beat three, quarter-note hats and a late tom.
Machine walk
Steady kick steps with an alternating rim pulse and off-beat eighth-note hats.
Neon crossbeat
A fast three-against-four kick pattern over a snare backbeat and eighth-note hats.
3:4
Each corner is a beatOne turn = four quarter notes

Tonal pulses, or your own recorded sounds.

Layers · 2 / 12
Original timing
Original timing

Record: 3, 2, 1, then up to four seconds. No microphone monitoring. Clips stay on this page until deleted or you leave. Each beat retriggers the clip.

Try a relationship
Explore the four linked wave views
How the shapes make a rhythm

All layers share a four-quarter-note cycle. At 90 BPM, it lasts 2.67 seconds. A triangle plays three evenly spaced beats in that time; a square plays four. A single dot plays once. Its small outer marker shows when. Two beats sit at the ends of a line. Off-beat shifts any layer by half its own beat interval: two four-beat layers interleave when one is off-beat. The shape rotates to show that timing shift.

The shapes show beats per cycle, not time signatures. Some combinations, such as 2 : 4, are simple subdivisions. Ratios such as 3 : 4 reveal the interlocking timing of a polyrhythm.

Linking adds the beat envelopes together to pulse the wave source’s amplitude. It keeps your frequency and harmonics. Rhythm clicks have their own percussion tones; the four views show the modulated source, with carrier motion slowed for visibility. The plate estimates its response rather than modelling transient ring-down.

Listen inside a track

Bring your own music.

Stays on your device. MP3, WAV, M4A or another browser-supported audio file. Up to 20 MB / 5 minutes.

Explore the rhythms in your music.

Choose a music file or try the synthetic 3:4 example. The browser looks for repeating attacks in four frequency ranges, then suggests a tempo and up to four regular rhythm layers. Press Sound on to hear the original recording and the rhythm voices together. The Blend slider moves between them without changing their timing.

Analysis uses up to 32 seconds at a time. You can choose another passage, correct the tempo, move the rhythm grid and adjust each layer’s timing. The passage loop uses whole shared cycles. Turning it off lets the original recording play through.

This is an experimental estimate, not instrument separation or a complete transcription. The downbeat and half-time or double-time interpretation can be ambiguous. Swing, syncopation and changing tempos may not fit an evenly spaced polygon. The four linked wave views follow the estimated beat envelopes, not the recording’s full waveform.

Files stay on your device, with no server upload. The current limit is 20 MB and five minutes to keep memory use bounded on phones. Analysis runs in a background worker; audio is optional and pauses when you leave the experiment.

Make your own kit.

Switch to Drum kit and assign any layer to a kick, snare, hi-hat, cymbal, tom or percussion sound. Rock / metal, 808 and cyberpunk presets use recorded drum samples while keeping your rhythms. The hybrid kits respond to velocity with changes in level and timbre, and the 808 uses recordings from the original hardware. Up to twelve layers share the same transport. Sample sources and licences.

Press Record on a layer to make a sound of your own. Allow the microphone, wait for 3, 2, 1, then capture up to four seconds. Stop early if you like. Hear previews the sound; each beat retriggers it. You can replace or delete a clip, and switch between it and a drum part. Clips stay in browser memory and disappear when you leave the page.

What is a polyrhythm?

A polyrhythm combines contrasting rhythmic divisions at the same time. In 3 against 2, one layer plays three evenly spaced beats while another plays two in the same duration. Both meet again at the start of the next cycle.

Here, each shape represents beats per shared cycle. A dot plays once; a line has two endpoints; a triangle has three corners; a square has four. Adding sides adds beats. The ratios describe divisions, not time signatures. A 2:4 pattern is a simple subdivision rather than the contrasting relationship of 3:4.

Try three against four.

  1. Choose the 3:4 preset and press Play.
  2. Switch Sound on to hear the two percussion voices.
  3. Follow the triangle and square. Listen for the point where their beats coincide.
  4. Slow the tempo, then add a fifth-beat layer.