Overdub

What is this?

A synthesiser that records itself. Play the keys with the mouse, with touch, or with your computer keyboard, which covers both octaves at once: Z–M is the lower one and Q–I the upper, each with its black keys on the row above, in the gaps where they sit on a piano. , and . shift the octave, and ; and ' step through the waveforms.

Instrument is the sound itself, before any of it is recorded. Brightness closes a filter over the whole thing — slide it down and everything goes dark and muffled. Resonance makes that filter sing at its own edge, so sweeping brightness with resonance up is the noise a synthesiser is famous for. Attack and Release are how quickly a note arrives and how long it takes to go: short for a pluck, long for something that swells and hangs on after you let go.

Space puts that sound somewhere. Echo repeats it, a little darker each time, and Room surrounds it with walls. Both are built here in the page — the room is generated, not a recording of a real one. Output is the master volume, for when the whole thing is louder than you wanted.

Hit record, play a phrase, and stop: that phrase sets the length of the loop, and it repeats. Play over the top and each pass stacks up, and what you add comes back round a loop later while you are still recording it. Pause (or /) holds the loop where it is without stopping the keys, so you can work out what to play next over silence.

The loop is as long as you held record for, which is always a little longer than you meant. Trim cuts it off after the last note, and the two ×2 buttons make it longer — one keeping everything repeating exactly as it is, the other letting it play once and leaving space to answer into.

Every layer keeps what you played, so the controls beside it only change how it is heard and none of them can spoil it. Play it backwards, play it twice a loop, shift it later against the others, or give it a different tone; press again to undo. The last two silence the layer and throw it away, and the slider underneath sets how loud it sits against everything else — the middle is exactly as you played it.

There is no wrong note and nothing keeping score. Every sound is generated in the page as you play it — nothing here is a recording.