How to play a synth with your computer keyboard

Playing a synth from the letters on your computer keyboard is built into Loop by Zaweba. Select a track with an instrument on it and the keys A W S E D F T G Y H U J K play it like a piano, with Z moving the octave down and X moving it up. There's an on-screen keyboard as well if you'd rather click the notes with the mouse.

So you don't need any extra hardware to try out a sound, work out a melody or record a part. Here is how the layout works, how to use it to record, and when it is worth reaching for something else.

How the letters map to a piano

Look at the middle row of letters, A S D F G H J. Those are the white keys. The row above, W E T Y U, sits between them in the same places as the black keys on a real piano: W between A and S, E between S and D, then a gap where there is no black key, then T, Y and U. K carries on to the next white key. If you have ever looked at a keyboard from above, the shape will feel familiar after a minute or two.

That gives you a bit more than an octave under one hand. When the tune climbs out of reach, press X to move up an octave; press Z to come back down. It's worth glancing at which octave you are in before you record, because the same letter can sound very high or very low depending on where you left it.

Choosing something to play

The keys play whatever instrument is on the selected track. In Studio mode (View > Studio mode, or F3) you can add the built-in synth with Track > Add synth track, a drum machine, a sampler, or one of the 128 General MIDI instruments from Track > Add General MIDI track.

The synth is a good first choice for this. It has 28 presets, from soft pads to sharp leads, and two oscillators, a filter and envelopes to shape your own. Pick a preset, select the track, and start pressing keys. On a drum machine track the same keys trigger drum sounds instead of notes.

Recording what you play

Notes from the on-screen keyboard and the computer keys can be recorded onto an instrument track in the same way as a USB MIDI keyboard. Turn on the metronome with M, set a count-in of up to two bars, and press R to record. Every pass over the same place is kept as a take, so you can play a line three or four times and choose the best one afterwards from the clip's right-click menu.

Once it is recorded, the part is ordinary notes. Open the piano roll to move a wrong note, fix timing with quantise, or adjust velocity, which is handy here because computer keys can't play loud and soft the way a real piano key can.

When it feels a little late

Loop plays through shared-mode Windows audio with a buffer you set in Tools > Preferences, from 10 to 200 ms. If notes seem to arrive a moment after you press the key, try a shorter buffer. If the sound starts to crackle, go back up a step. A short buffer feels more immediate; a longer one avoids dropouts.

Making the most of it

The computer keys are best for sketching. Hum a tune, find it on the letters, record it roughly, then tidy it in the piano roll. If you aren't sure which notes will fit, the piano roll highlights the song's scale, and snap to scale keeps notes inside it.

When you find yourself wanting more reach or a feel for loud and soft, a USB MIDI keyboard records the same way. Until then, the keyboard you already have is enough to write a whole song.