What is MIDI velocity?
Velocity is the number a MIDI note carries to say how hard the key or pad was hit, from 1 to 127. A soft touch sends a low number and a hard strike sends a high one. The instrument decides what that means, and it is usually loudness and brightness together. Velocity 0 is a special case: a Note On with velocity 0 means note off.
I make InputConfig, a free Mac app that reads and sends MIDI notes, and the last section says how velocity works with buttons, which cannot feel how hard they are pressed.
On this page: 8 sections
Steps
- Open a MIDI tester, press Start listening and play one key softly, then hard.
- Read the lowest and highest velocity it reached.
- If hard playing never gets near 127, or soft playing is already loud, change the velocity curve on the keyboard.
- If one key stands out, that key's sensor is worn or dirty.
See where velocity sits in a note
| Byte | Value | Meaning |
|---|---|---|
| Status | 0x90 to 0x9F | Note On, channel 1 to 16 |
| Note number | 0 to 127 | Which note |
| Velocity | 1 to 127 | How hard. 0 means note off |
Velocity is the third byte of every Note On, so each note carries its own. The MIDI note number chart covers the second byte.
InputConfig is free on the Mac App Store. macOS 14 or later, no account, no tracking, open source.
Know why velocity 0 is a note off
MIDI has a Note Off message, and it also treats a Note On with velocity 0 as a note off. Many keyboards send the second kind, because a run of messages of one type can be sent more compactly. A monitor may show either, and both end the note. A Note On with velocity 0 is not a very quiet note, it is the end of one.
Know what the instrument does with it
Velocity is only a number until a sound uses it. A piano sound plays louder and brighter, a drum sample may switch to a harder hit, and an organ sound may ignore it. The same key press can sound different on two instruments that map velocity differently. If everything plays at one loudness, the sound is ignoring velocity, or the keyboard is sending a fixed value.
Test a keyboard's velocity
Open the MIDI tester, play one key as softly as you can and then as hard as you can, and read the velocity range. A healthy key covers most of 1 to 127. A key stuck at one value, or one that never rises past a low number, points to a worn sensor. If every key tops out early, look for a velocity curve setting on the keyboard.
One key that reads differently from its neighbors is a hardware fault, and all keys reading alike is a setting.
Use velocity with buttons
A game controller button, a computer key and most foot switches are either down or up, so they cannot report how hard they were pressed. In InputConfig, each MIDI Note output plays at the velocity set in its row, from 1 to 127. For dynamics, put expression on a trigger: it sends every value in between, so a trigger on CC 11 swells the sound the way a harder strike would.
Fixed velocity on the buttons and expression on a trigger makes a controller playable. MIDI output has the setup.
The short version
- What. How hard a note was played, 1 to 127.
- Zero. A Note On with velocity 0 ends the note.
- Effect. Whatever the sound maps it to, usually loudness and tone.
Velocity travels with every note, and the instrument gives it meaning.
Questions
What is the MIDI velocity range?
1 to 127 for a sounding note. A Note On with velocity 0 is treated as a note off.
What does velocity 127 mean?
The hardest possible strike. It is the top of the range, and most sounds play at their loudest and brightest.
Is MIDI velocity the same as volume?
No. Velocity is a per-note value that the sound usually maps to loudness and tone. Volume is CC 7, which turns a whole channel up and down.
How do I test MIDI velocity?
Play a key softly and then hard in a MIDI tester and read the lowest and highest velocity. A healthy key covers most of the range from 1 to 127.
Why does my keyboard always send the same velocity?
It has no velocity-sensing keys, or it is set to a fixed velocity. Look for a velocity curve or fixed velocity setting in the keyboard's own menu.
Why is my MIDI keyboard so quiet?
A light touch sends low velocity numbers, and most instruments play those quietly. Look for a velocity curve or touch sensitivity setting on the keyboard, or raise the instrument's volume. A MIDI tester shows the numbers your playing sends.
Related
Free. macOS 14 or later. No account, nothing leaves your Mac. Open source on GitHub.
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