What You Can Do With MIDI Velocity
Velocity is one of the most useful pieces of performance information stored in a MIDI sequence. Two notes can have the same pitch, start at the same musical position and last for the same duration while producing different responses because their velocity values differ.
That makes velocity editing useful when a sequence feels too uniform, too aggressive, too restrained, or simply needs its dynamic values reorganized before being sent to another instrument.
- Set selected notes to one consistent velocity.
- Increase or reduce existing velocities proportionally.
- Add a fixed amount to the current values.
- Subtract a fixed amount without creating invalid values.
- Edit all MIDI channels or one channel at a time.
- Compare the original and resulting velocity range.
- Download the edited performance as a new MIDI file.
Set mode: make velocities consistent
Set mode replaces the velocity of every affected Note On event with the same chosen value. This is useful when consistency matters more than preserving the original dynamic differences.
Because the note numbers and event positions are not moved, the musical pattern remains in place. Only the selected Note On velocity bytes are replaced.
Scale mode: keep the dynamic relationships
Scaling works differently. Instead of forcing every note to one value, it multiplies each existing velocity by a percentage. A 75% setting reduces the values proportionally, while 125% raises them.
Values that would exceed the permitted range are limited to 127, and sounding Note On events are kept at a minimum velocity of 1.
Add or subtract velocity
The offset mode adds the same numeric amount to each selected velocity. Positive values increase it; negative values reduce it. Unlike scaling, the numerical distance between notes is preserved until a value reaches the upper or lower boundary.
Why Note On velocity 0 is treated differently
MIDI permits a Note On message with velocity 0 to be interpreted as a note-off event. For that reason, the editor does not turn those zero-velocity messages into sounding notes.
Actual Note Off velocity, when present in a Note Off message, is also left unchanged. The tool concentrates on the attack velocity of sounding Note On events.
Editing one MIDI channel
Multi-part MIDI files can contain events on several channels. The channel selector allows the velocity operation to affect the complete file or only Note On events assigned to one channel.
This can be helpful when one part needs adjustment while the dynamic data on other channels should remain exactly as it was.
Velocity does not equal audio volume
A higher MIDI velocity does not guarantee a fixed increase in acoustic loudness. MIDI sends a value to the receiving instrument, but the instrument's programming determines what that value controls and how strongly it changes the resulting sound.
A piano library might use velocity to select different samples and alter level, while a synthesizer patch could map it to amplitude, filter behavior or several parameters at once.
MIDI performance before audio production
Velocity editing is most useful while the performance is still MIDI and therefore easy to modify. Once a synthesizer, sampler or hardware instrument has rendered that performance into audio, the result is a waveform rather than editable MIDI note messages.
For broader browser-based experiments with sound and music data, explore Audio Tools for Recording, Mixing, and Ear Training. If the MIDI arrangement will later be performed on a real instrument, the Instrument Recording page covers the recording stage.
Velocity and musical expression
Repeated notes with identical velocities can sound intentionally controlled with one instrument and unnaturally repetitive with another. Conversely, large velocity differences can produce more variation than a particular part needs.
There is no single correct velocity curve for every instrument. Editing is most useful when you listen to the MIDI through the sound source that will actually perform it and decide whether its response suits the arrangement.
If you are developing a complete song rather than only MIDI data, Song Demo Production looks at moving an idea toward a recorded demo, while Blues and Country Recording shows how recording choices can differ with musical context.
Velocity and timing are independent
Changing velocity does not move a note earlier or later. It also does not shorten or lengthen the note. Those properties are represented by the positions of the MIDI events in the sequence.
This separation lets you reshape dynamic response while preserving a performance whose rhythmic feel is already working.
Velocity before recording vocals or instruments
Programmed parts can be refined before live material is recorded around them. Adjusting MIDI dynamics first can make the arrangement easier to evaluate without permanently changing any recorded audio.
Musicians preparing to record can use the First Time Recording Studio Guide, while singers can read How Long Does Vocal Recording Actually Take? for a separate look at vocal-session planning.
From MIDI dynamics to an audio mix
When the MIDI performance drives an instrument and that instrument becomes audio, the workflow changes. Audio signals can then be balanced, panned and processed as part of a mix.
You can experiment with those concepts in the Interactive Online Audio Mixer or explore mixer controls with the Mixer Console Simulator.
Keeping expressive information intact
Set mode deliberately removes velocity differences from the selected notes. Scale and offset modes behave differently because they begin with each note's existing value.
If the original performance already contains useful dynamic detail, scaling can often retain more of those relationships than replacing every velocity with a single number.
Performance preparation is not only technical. The Musician Psychology and Recording Confidence guide looks at the human side of preparing to perform and record.
Velocity and mixing are different controls
MIDI velocity influences how the receiving instrument responds when a note is triggered. A mixer fader controls an audio signal after the instrument has produced sound. They therefore operate at different stages of a production.
Once MIDI instruments and recorded parts are committed to audio, Mixing and Mastering covers the later production stage.
Using MIDI alongside recorded performances
A production can combine MIDI-controlled instruments with recorded vocals, acoustic instruments and other audio sources. Editing MIDI velocity remains separate from processing those recordings.
For projects built around recorded songs and instruments, see Music Recording. Spoken and sung material has its own requirements, covered in Vocal and Speech Recording.
Saving an edited copy
When you download the result, JavaScript copies the source MIDI bytes and replaces only the selected Note On velocity bytes. The result is packaged as a Blob and offered as a separate .mid file.
Keeping the source file separately makes it easy to return to the original performance data if you later decide that a different velocity treatment works better.
Continue working with music and audio
MIDI editing is one part of a much larger production process. Audio Content Recording Services covers work with recorded audio content, while the Music Genre Recording overview explores recording across different musical settings.
For more focused browser utilities, return to Audio Tools for Musicians.