Velocity, Swing and Humanising

A pattern with every hit at full velocity, exactly on the grid, sounds like a machine. Sometimes that is the point. More often it sounds lifeless. Two tools fix it: velocity (how hard each note is hit) and timing (where it lands relative to the grid). Swing is the controlled version of timing; humanising is everything else.

Velocity: the cheapest groove there is

Velocity runs from 1 to 127 in MIDI. On drums it changes loudness and, in a good sampler, the tone too, since a soft snare hit is darker than a hard one.

Real drummers accent in predictable ways. Copy them:

Step:     1  2  3  4  5  6  7  8  9  10 11 12 13 14 15 16
Hat vel:  110 60 90 55 105 60 90 55 110 60 90 55 105 60 90 55

The downbeats are loudest, the 8th off-beats are medium, and the in-between 16ths are soft. That three-level shape alone makes a hat line feel played.

Other velocity habits worth stealing:

• Ghost notes on the snare at 20–40 velocity, just before or after the main backbeat, add funk without cluttering the loudness.
• Fills crescendo. Ramp velocity up across a fill so it lands into the downbeat.
• The backbeat is consistent. Vary hats freely, but keep snares on 2 and 4 within a narrow range; a weak backbeat sounds like a mistake.

Swing: delaying the off-beats

Swing pushes every second note of a subdivision later. With 16th swing, steps 2, 4, 6 and so on move towards the next step; steps 1, 3, 5 stay put.

Swing amount is usually expressed as a percentage, a convention from Roger Linn's drum machines and the Akai MPC:

Swing %	What it means	Feel
50%	Straight; off-beat exactly halfway	Machine-straight
54%	Slightly late	Loosens 16ths without sounding swung
58–62%	Clearly late	Classic boom bap and lo-fi range
66%	Triplet position (2:1)	Full shuffle
66–68%	Past triplet	Heavy, lazy, "drunk" feel

The percentage is the share of the pair's length given to the first note. At 66% the first 16th takes two thirds of the pair and the second takes one third, which is exactly a triplet.

How much swing to use

• House and techno: 50–56%. A touch of swing on hats or shakers adds shuffle without blurring the kick.
• Boom bap, lo-fi: 56–62%, sometimes more on the hats than the kick.
• Trap and drill: mostly 50%. The bounce comes from rolls and triplets, not swing.
• Shuffle blues, swing jazz: at or past 66%, and real jazz swing actually varies with tempo, getting straighter as the tempo rises.

Apply swing to the parts that play the swung subdivision. If your hats play 16ths and your kick plays 8ths, 16th swing only moves the hats, which is usually what you want.

Humanising without slop

"Humanise" buttons usually add random timing and velocity changes. Random jitter is the least musical way to do it. Measurements of real drummers show that much of their deviation from the grid is systematic, repeating from bar to bar rather than random, and in listening tests hits shifted early were rated worse than the same shift late. What sounds human is consistent deviation:

• Push or pull a whole part. Nudge every snare 5–10 ms late for a laid-back feel, or hats 3–5 ms early for urgency. The consistency is what reads as intent.
• Keep the kick on the grid. It anchors everything else.
• Small velocity randomness is fine. Plus or minus 5–10 on hats adds life. Timing randomness is riskier; keep it under about 5 ms if you use it at all.

A worked example

Start with a straight boom bap loop at 90 BPM, all velocities at 100.

1. Shape the hat velocities into the three-level accent pattern above.
2. Add two snare ghost notes at velocity 30, on steps 8 and 15.
3. Set 16th swing to 58%.
4. Nudge every snare 8 ms late.

Play the before and after back to back. The notes have not changed; the groove has.