Rap Beat Maker

It is a step sequencer set up for rap: a grid of six rows and sixteen columns. Each row is a drum sound (kick, snare, hi-hat, open hat, clap and 808) and each column is a sixteenth note, so one pass across the grid is one bar. A lit square plays its sound when the playhead reaches it.

The page opens on the Boom bap pattern at 90 BPM, with a little swing built in so the kick on step 10 lands a touch late. The Pattern menu swaps in Trap at 140, Drill at 142, Lo-fi at 78 or West Coast at 96, and the Tempo slider moves anywhere from 60 to 180 BPM. Variation flips a few hi-hat, kick and 808 hits of the current preset; Clear empties the grid.

Every sound is synthesised in your browser, so no samples download and the loop starts at once. The WAV button saves four bars of your pattern as an audio file, and Save link keeps the grid in a web address. It is a place to build a rhythm, write bars over it and learn how rap drums are put together.

Boom bap is named after its two main sounds: "boom" is the kick, "bap" is the snare. The snare owns beats two and four, steps 5 and 13 on this grid, and it almost never moves. The kick opens the bar on step 1 and then plays around the snare: here on step 7, two sixteenths after the first snare, and on step 10, a sixteenth after beat three.

Hi-hats tick in eighth notes on the odd steps, one open hat on step 15 lifts the end of the bar, and the 808 doubles the kick. Tempo usually falls between 85 and 95 BPM. At that speed there is space between hits, so small shifts of a single kick change the whole groove.

• Snare: steps 5 and 13, every bar
• Kick: step 1, then off-beat hits such as 7 and 10
• Hi-hat: every second step for eighth notes
• 808: under the kick, on the same steps
• Open hat: once per bar, late, as a lift

At 90 BPM one bar lasts about 2.7 seconds, which is room for roughly 10 to 14 syllables. Aim your rhyme at the snare on step 13, the fourth beat, and let the syllables before it fall on or between the hats. That landing spot is what rappers mean by the pocket.

If your words keep tripping, slow the slider by five BPM before you rewrite anything. If the verse drags, speed up until the last word of each bar reaches the snare without you stretching it. Then keep that tempo for the whole song.