A first sampled instrument

Play a few keys on the instrument below. Every note you hear is a real recording, played back at different speeds to make different pitches. That's all a sampler is, and it's one of the most fun ideas in music technology. In the 1960s the Mellotron played strips of tape with real strings and flutes recorded on them, one per key; in the 1980s samplers like the Fairlight and the E-mu Emulator let anyone record any sound and play it as an instrument. Producers sampled glass bottles, car doors and their own voices.

By the end of this project you'll have your own: a small instrument made from a sound in your life, a mug you tap, a guitar string, your voice humming one note, with soft and hard versions and a couple of alternate takes so it feels alive. Then you'll write a short piece on it, the kind of thing you play for a friend and watch them ask "wait, what is that sound?"

Before you record anything: when a sampler plays your recording an octave higher, does only the pitch change, or something else too? The instrument above has the answer.

Stage 1: Plan twelve recordings

A good small instrument isn't a huge folder of sounds; it's a few recordings chosen on purpose. Here's the plan:

• Three notes across a comfortable range, for example C4, E4 and G4. Each recording will cover the keys around it.
• Two strengths of each: one played softly, one played firmly. Soft and hard playing sound different, not only quieter and louder.
• Two takes of each, so repeated notes don't sound like a machine.

That's three × two × two = twelve short recordings.

If your sound has no clear pitch, like a tapped box or a door, make a little kit instead: each key a different hit. Same plan, no tuning to worry about. If you'd rather start from a description than a microphone, Generate a drum kit builds a kit like this from generated hits and maps it the same way.

Record the first note only, on your phone if that's what you have. Keep the mic and the room the same for everything that follows. Listen back: is there hum, clipping, or a cut-off start? Fix it now, while it costs one recording rather than twelve.

Checkpoint: one clean test note that you'd be happy to hear on its own. Planning and recording samples covers mic position, levels and room.

Stage 2: Trim without cutting the life out

Now record the other eleven, then trim each one. The start matters most: a sample has to begin exactly when the sound begins, or every key you press will feel late. Cut too late and you lose the attack, the click or breath that tells your ear what the instrument is.

Move Start in the lab until the note begins the instant you press play. Then try cutting a little too late. The pluck goes soft and the note sounds like it's fading in. Now you know where the attack lives, and you can protect it in all twelve of your recordings.

Leave the natural tail at the end too. And don't make the soft and firm takes the same loudness: the difference between them is half the expression of your instrument.

Checkpoint: twelve trimmed recordings, named by note, strength and take, with the originals kept separately. Preparing samples goes deeper on fades and clicks.

Stage 3: Map them to the keyboard

Load your recordings into a sampler that lets you set a root note, a key range and a velocity range for each one. The Maru Studio sampler works; so does the sampler in most music software. Follow the map in the figure: each note covers a few keys around it, soft takes on low velocities, firm on high.

Then play across the keyboard slowly and listen at the edges, where one recording hands over to the next. Remember the answer from the top of the page: playing a recording higher makes it shorter and snappier, and lower makes it longer and duller. Push one recording too far and it stops sounding like your instrument. If a seam jumps out, move the boundary or record another note there, then play across it again.

One practical note: if your recordings are private, check where your sampler stores them. The online Studio uploads samples to your project storage; a desktop sampler keeps them on your machine.

Checkpoint: every key sounds at soft and hard velocities, with no gaps. Key and velocity mapping shows how to find and fix seams.

Stage 4: Shape the endings

How does a note end when you let go? A tapped mug rings out on its own; a hummed note stops when the breath does. Set the sampler's Attack and Release for the job, as in the instrument at the top. A short release makes it tight and percussive; a longer one lets notes overlap gently.

Release can't make a recording longer than it is. If a note runs out too soon, record a longer one, or loop a steady part of it. Now your instrument ends notes the way you want, not the way the file happens to stop.

Checkpoint: a held note and a fast repeated note both sound right. Loops and releases explains looping without clicks.

Stage 5: Make repeated notes feel human

Play the same key four times fast. If every hit is the identical recording, your ear catches it at once; people call it the machine-gun effect. Set the two takes of each note to alternate (samplers call these round robins). Now repeated notes vary slightly, the way a real player's would.

If one take is noticeably later or louder, fix that take rather than calling it realism. Variation should be in color, not timing.

Checkpoint: four fast repeats sound like playing, not like a stuck button. Round robins and articulations covers more ways to add variety.

Stage 6: Export it and give credit

Export the instrument as a bank file and reload it in a fresh session to check every sample comes back. Add a credit line: who recorded it, what the sound source was, when. If anything wasn't recorded by you, note exactly where it came from and that you're allowed to use it.

For a first bank, keep the features simple: hard switches between soft and firm layers rather than crossfades, and no keyswitches. Simple banks open in more places.

Checkpoint: the exported bank reloads cleanly with its credits. Shipping a sample library carries this further.

Stage 7: Write a piece for it

Every instrument has something it does better than anything else. Maybe yours has a beautiful soft layer, or a low note with a long ring, or a rattle that sounds great on repeated hits. Write a short piece, thirty seconds is plenty, that shows that off. Start simple: one motif, repeated, then changed once. Leave space for the sound itself.

Record it and play it for someone without telling them what it's made of. That moment when they find out the haunting bell sound is a coffee mug is why people have been sampling things for sixty years.

Checkpoint: a recorded piece and the bank it was played on, in one folder. Composing with a library has more ideas for writing to an instrument's strengths.

Quick check

1. You transpose a soft piano note up an octave and it suddenly sounds plucky. Why? The sampler plays the recording twice as fast, so the attack is twice as sharp and the note half as long. That's why you record several roots instead of stretching one across the whole keyboard.
2. You alternate two takes of each note, but fast repeats still feel wrong: every second hit lands a little late. Is that the realism you wanted? No. Round robins should vary the color of a note, not its timing. Trim the late take so its attack starts where the other one does.
3. You set a long Release but the note still stops abruptly. Why? The recording ran out. Release fades the sound you have; it can't create sound that wasn't captured. Record a longer note or loop part of it.

Next steps

• Use it: Presets as product design. Give the bank starting sounds that show different playing jobs.
• Sideways: Granular synthesis. The same recordings, chopped into tiny grains, become clouds and textures instead of notes.