MIDI Notes & Velocity
MIDI represents every musical note as a number from 0 to 127. It also records how hard each note is played using a separate number called velocity. Together, note number and velocity give you precise control over pitch and dynamics - the note number picks the ingredient, velocity sets the heat.
Note Numbers (0-127)
Each semitone on the keyboard gets a number - like numbering every ingredient in the pantry. The pattern is simple: going up one semitone adds 1. Going up one octave adds 12 (because there are 12 semitones in an octave).
| Note | MIDI Number | Common Use |
|---|---|---|
| C1 (24) | 24 | Sub bass |
| C2 (36) | 36 | Bass notes, kick drum (GM) |
| C3 (48) | 48 | Low chords, bass guitar upper range |
| C4 (Middle C) | 60 | Reference point - centre of the keyboard |
| C5 (72) | 72 | Melodies, lead lines |
| C6 (84) | 84 | High melodies, sparkle |
| C7 (96) | 96 | Very high - effects, bells |
Note: some DAWs label middle C as C3 instead of C4. The MIDI number (60) is always the same regardless of labelling.
Quick Formula
To find any note's MIDI number: start with C in that octave and count semitones up. C4 = 60, so D4 = 62 (two semitones up), E4 = 64, F4 = 65, and so on. Or remember that each octave is 12 apart: C3 = 48, C4 = 60, C5 = 72.
Velocity (0-127)
Velocity measures how hard a note is played, on a scale from 0 (silent) to 127 (maximum force). It's called velocity because on a real piano, the speed at which the hammer hits the string determines the volume and brightness. MIDI adopted the same idea.
Velocity in Practice
Velocity isn't just volume. Most virtual instruments respond to velocity in multiple ways:
Volume
Higher velocity = louder note. The most basic response.
Brightness
Harder hits often open the filter, making the tone brighter and more cutting.
Sample Selection
Realistic instruments switch to different recordings at higher velocities - a softly played piano sounds completely different from a hammered one.
Attack Speed
Higher velocity can trigger faster attack times, making notes punchier and more immediate.
Why Velocity Variation Matters
Real musicians never hit every note at exactly the same velocity. If all your MIDI notes are at 100, the part will sound mechanical and lifeless. Even small random variations (say, 90-110 range) make a huge difference. Intentional accents (louder on beat 1, softer on off-beats) make it sound like a real performance. Many DAWs have a "humanise" function that adds subtle velocity and timing variations automatically.
Try it
MIDI note numbers map directly to pitches, and velocity changes the feel even when the pitch stays fixed.
Velocity shapes the groove even before you change pitch.
Then tap these to hear how MIDI numbers correspond to notes on the keyboard:
Every 12 MIDI numbers = one octave higher
Key takeaway
MIDI notes 0-127 map every pitch across the full range. Velocity 0-127 captures dynamics - how hard each note is played. Together they give precise, editable control over both pitch and expression.
Next: how to tighten up timing and add groove to your performances - quantisation.
See MIDI numbers in action
Starts generates MIDI with varied velocities and note ranges you can export and study.