Beat maker: a drum machine in your browser

Reading the grid

• One line across is one sound. The button at the start of the line plays that sound once, so you can hear what it is.
• Sixteen squares make one bar. The bar is counted in four beats, and each beat is four squares. The lighter squares with the numbers 1, 2, 3 and 4 are where the beats fall.
• The light moves from left to right, one square at a time, and starts over. A square that is on sounds when the light reaches it.
• A square that is on turns gold and shows a dark dot. With the beat stopped, turning a square on plays its sound once.
• On a narrow screen each line is folded in two: squares 1 to 8 on top, 9 to 16 underneath.
• With a keyboard: Tab reaches the grid, the arrow keys move from square to square, and Space or Enter turns a square on or off.
• The beat in words, under the grid, says the same thing as the squares: which sound is on which squares.

Tempo and swing

• Tempo is how fast the beat goes, in beats a minute. This page goes from 60 to 180.
• Swing holds back every second square a little. At 0 the sixteen squares are evenly spaced. At 10 the late squares land a third of a square behind, and the beat rolls instead of marching.
• Tempo and swing can be changed while the beat plays.

The eight sounds

• Kick: the low thump. Tom: a rounder, higher thump.
• Snare: the crack. Clap: a hand clap. Rim: a short, dry knock.
• Closed hat: a short tick. Open hat: the same, left to ring.
• Cowbell: a short, hollow tone.

None of these is a recording or a sample of anyone’s record, and none is AI-made audio. Each one is arithmetic: the code adds up sine waves, square waves and random numbers, the way early drum machines made their sounds with circuits. They sound like a machine, not like a drum kit in a room.

The five starting points

• Backbeat: kick on beat 1 and around beat 3, snare on 2 and 4, a steady hat. The page opens with this one.
• Four on the floor: a kick on every beat, a clap on 2 and 4, an open hat in between.
• Slow, with swing: a slower beat with the swing turned up.
• Half time: a fast count with the snare only on beat 3, so it feels half as fast.
• Three-two clave: the rim plays five strokes, three and then two, a pattern heard all through Cuban music and the music that grew from it.

A starting point replaces the squares, the tempo and the swing. “Bring back what was there” undoes it, once.

Keeping a beat

• The link holds the squares, the tempo and the swing, written after the # in the address. Browsers do not send that part of an address to a website’s server. The address in your browser follows the beat as you change it, so a bookmark keeps it.
• Anyone with the link gets the same beat when they open it. The link holds nothing else: not your name, not your device, not when it was made.
• The sound file is a WAV file, made on your device: 1, 2, 4 or 8 times through the bar. Many music programs and phones can open a WAV file. The page puts no name, no mark and no tag inside it.
• The file is made to go round. What rings past the end is folded onto the start, so a program that repeats it has no gap.
• Volume is not in the link or the file. The file is always made at the same level.

What this page can’t do

• Nobody has listened to it yet. The AI that wrote this page cannot hear. A program checked the sounds as numbers: that each one starts at once, dies away to nothing, and is not too loud. Whether they sound good is for your ears. If one is harsh or wrong, please write to us.
• It cannot tell how loud your phone, speaker or headphones are.
• It has one bar of sixteen squares. No second bar, no triplets, no notes or bass line, no loudness for each sound, no recording of your voice.
• The beat may stutter or stop when the page is in the background or the screen locks. On some phones the switch that silences the ringer silences web pages too. We have not been able to test this on a real phone.
• Wireless speakers and headphones often play a little late, so the moving light can run ahead of what you hear.
• It keeps nothing. Close the page without the link or the file, and the beat is gone.
• It was tried by a program in one browser, with a mouse and a keyboard. It has not been tried on a touch screen or with a screen reader.

Look after your hearing

• Start low. Drum sounds hit hard at the front. The volume slider opens at 60 of 100 on purpose; your device’s own volume matters more.
• Loud sound for a long time can damage hearing. With headphones or earbuds a person can go too loud without noticing.
• If your ears ring or sounds seem dull afterwards, it was too loud.