Drum synthesis

Press Hit on the synth below. That's not a kick. It's a laser: a "pew" from an old arcade game, a tone sliding down from high to low. Now drag Drop from 400 milliseconds down toward 40, and hit again after each change.

Before you do: if the same slide happens ten times faster, will you hear a faster zap, a click, or something else?

What just happened?

Somewhere along the way, for most ears well under 100 milliseconds, the zap stopped sounding like a slide and turned into a thump. You didn't add anything. The kick was a laser all along, played so fast that your ear can't follow the pitch moving. Instead it hears the rapid fall as an impact: the punch at the front of the hit.

That's the classic recipe for an electronic kick. Roland's TR-808, released in 1980, made its bass drum from a ringing, sine-like tone with a slight pitch drop at the start. Turn its decay up and that tone becomes a long, booming low note, the "808" that hip-hop, and later trap, built entire bass lines from. The TR-909, a few years later, had a punchier kick with more click on top, and it became the sound of house and techno. Same ingredients, different balance.

A kick synth has two separate paths, and it helps to keep them apart in your head:

• the pitch path: where the tone starts (Start), where it lands (End) and how fast it gets there (Drop);
• the level path: how quickly it starts and how long it rings (Decay).

Lengthen Decay and the kick grows a long, pitched tail, 808 style. Shorten it and it's a tight, dry thump. The pitch path didn't change; only how long you hear the result.

Punch without turning it up

A kick feels punchy when something happens fast at its front. The pitch drop is one way to get there, and you've just heard it. Notice that your fast-drop kick felt harder-hitting than the slow one without being any louder. Punch is a shape in time, not just volume.

The second way is a click: a tiny burst of high-frequency sound right at the start. Reveal Click and bring it up a little. On big speakers it adds definition; on a laptop or phone, it's often the only part of the kick you hear at all, because small speakers can't reproduce the 50 Hz body. A good click is the kick's handshake with small speakers.

The ending pitch is a musical choice

End sets the note the kick's body settles on. With a short decay, nobody hears it as a note; it's just "low". With a long, 808-style tail, it's absolutely a note, and it will either agree or argue with your bass line.

Try End at 55 Hz, which is an A, and then 49 Hz, a G. With a long decay, you'll hear the kick change key. If your track is in G, the 49 Hz tail locks in with the bass; the 55 Hz one clashes for as long as it rings. That's why producers who use long 808s tune them like a bass instrument. But it's a choice for kicks with a clear pitched tail. A short, punchy kick has no audible note to tune, and fussing over its root is time better spent on its length.

One more thing about this synth: each hit is a complete one-shot, set the moment it starts. Change a control, then hit again to hear it.

Snares: a drum and a rattle

A real snare drum is two sounds at once: the drum skin ringing at a pitch, and the snare wires underneath rattling against it. Synthesised snares copy that: a short, tuned tone for the body, plus a burst of noise for the wires. The 808's snare had a knob for exactly this balance, labelled "Snappy".

With Snap low, you hear mostly the tone: a pitched "dum", closer to a tom. Raise it and the noise takes over: the crack and fizz of a snare. Tune moves the body up and down; higher sounds tighter and more like a piccolo snare, lower more like a fat, loose backbeat. If the noise and the tone ever sound like two separate sounds, shorten Decay so they end together. (After a change, give it a moment and hit again; the new snare is rebuilt in the background.)

Hats: noise and metal

Hi-hats are mostly about the high end and length. White noise, kept very short, already sounds hat-like, as you might remember from the oscillators guide. But plain noise sounds a little like hiss. Real cymbals ring with lots of partials that don't fit any harmonic series. The 808 imitated that with six square-wave oscillators at unrelated pitches, mixed and filtered, which is why its hats and cymbals have that bright, metallic, almost chimey sizzle.

With Metal low, the hat is a short "tss". Raise it and it starts to ring, a clangy shimmer under the hiss. Lengthen Closed and the ring has time to speak. Leave Hit running to hear it as a steady stream: a bright, ringing hat can wear out the ear over a whole song, while one with no bite disappears behind the snare. Choose its job first: timekeeper, accent, or wash.

Where it breaks

Tails that crash into each other. A long kick tail sounds enormous on its own and turns to mud in a busy pattern. If the next kick, or the bass, starts while the last tail is still ringing, the low end blurs and eats headroom. Shorten Decay until the gaps between kicks come back.

A click that becomes its own sound. Too long or too loud a click stops being the front of the kick and becomes a separate tick floating above it. If you can hear the click as a separate event, bring it down or shorten it.

Pitch that's too slow. Somewhere between kick and zap, often around 100 to 200 milliseconds depending on the sound, is a no-man's-land where the drop is slow enough to hear as a slide but too fast to sound deliberate. Sometimes that's a style, like the pitch-swept electronic toms of 1980s Simmons kits. Usually, on a kick, it sounds like a mistake.

Same idea, different place: the kick and the bass are fighting for the same space, and the fix is usually about time, not EQ: which one rings, which one gets out of the way, and whether their notes agree. See Low end, where the kick's tail length and the bass's attack are tuned as a pair.

Make it yours

Build a kick for a loop you're working on. Start with the body: set End to the root of your track if you want a long, pitched tail, or anywhere that feels right if it's short. Set Drop fast enough to punch, but not so fast that the hit loses its weight; between 30 and 80 milliseconds is a good place to start. Set Decay so the tail stops before the next kick in your busiest bar. Then add just enough Click that you can still hear the kick on your laptop speakers at low volume.

When it works, open Kicker from the link at the top of the lab, which carries your settings, and save it with the track's name, so it's ready next time you open that project.

Quick check

1. Your kick sounds great soloed but disappears on phone speakers. Do you turn it up, or change something else? Add a little click, or raise the body's start pitch. Phone speakers can't reproduce 50 Hz, so turning the kick up mostly adds energy nobody hears. A short burst of high frequencies gives small speakers something to play.
2. A long, boomy 808-style kick clashes with your bass line in a minor key. What would you try first? Tune the kick's ending pitch to the root or the fifth of the key, or shorten its tail so there's no pitched note left to clash. A long pitched tail is a bass note; treat it like one.
3. You slow a kick's pitch drop from 40 to 400 milliseconds. What do you expect to hear? The punch turns into an audible slide, a laser "pew". The ingredients are the same; the speed decides whether your ear hears motion or impact.

Next steps

• Go deeper: Drum programming. You've built a kick, snare and hat. How do you turn them into a groove that feels played, not programmed?
• Sideways: Generate a drum kit. Describe a kit instead of building it, then judge the model's hits by the same decisions you made here: pitch, decay and one shared room.
• Explanation: Envelopes. The pitch path and the level path are both envelopes; here's how they work on any synth.