BeatMapper

Your screen becomes a beat machine. Tap nearly 400 sounds, from drums and chiptune to world languages and system sounds. Each loops on its own: no ordinary tracks.

BeatMapper turns your iPhone into a grid of coloured pads. Tap a pad to play its sound. Turn on Loop and the sound keeps repeating, so you can stack pad on pad and build a pattern while it runs. Tap a looping pad again to stop it.

Seventeen sound sets are built in: drum kit, percussion, music box, bass, sine tones, chiptune, everyday sounds, cartoon effects, sci-fi effects, interface sounds, phonemes, greetings from around the world, the English alphabet, English numbers, Japanese words, French words, and the system sounds. Nearly four hundred sounds in all.

Every pad shows what it is doing. A white square shrinks inside the pad as the sound plays, so you can see at a glance where each loop is in its cycle and how the parts line up against each other.

Three switches change how the pads respond. Loop repeats a sound instead of playing it once. Slide plays every pad your finger passes over, so you can sweep across the grid. Sustain lets a loop finish its round before it stops, so nothing is cut off mid-beat.

The pads fill the screen. The grid is worked out from how many sounds the set has, always at least four across, so the pads stay large enough to hit with a finger. Randomize shuffles the layout, keeping each sound with its own colour, and Reset puts them back in order.

Loop Length decides how repeats line up. Original Length leaves every sound as it is. Aligned pads them all to the longest one, so every pad repeats on the same beat. Staggered spreads them over 100 to 110 percent of that, so the phases drift slowly apart and the pattern keeps changing.

Other things you can set: polyphonic playback on or off, background playback so the sounds keep going when you leave the app, and whether the status bar and home bar are shown.

No account, no setup, no menus to learn. Open it and play.