MIDI Combiner
How to Combine MIDI Files: Merge vs Sequence Explained
6 min read·
Arrangements often arrive in pieces: piano in one file, bass in another, drums exported separately, and an outro someone sent later. Combining them into a single MIDI file makes the arrangement playable, shareable and easy to load into any DAW or player.
Merge or sequence — pick the right mode
There are only two sensible ways to combine MIDI files, and choosing the wrong one is the most common mistake.
- Merge tracks: all files start at time zero and play simultaneously. Use this for parts of the same song — piano, bass, drums, strings.
- Sequence: each file starts after the previous one ends. Use this for sections of a set or arrangement — intro, verse, bridge, outro.
What must survive the combine
A safe combiner rewrites as little as possible. Everything that makes the performance sound human should carry over untouched.
- Note timing, duration and velocity
- MIDI channels and track names
- Instrument and program changes
- Tempo and time signature events
- Control changes, sustain pedal and pitch bend
Handling different tempos and keys
If the source files disagree on tempo, you have two options: keep each file's original tempo map, which is right for sequencing distinct sections, or apply a single BPM to the whole output, which is right for merging parts that must lock together.
Keys are different. A combiner should never transpose automatically — that would silently change your music. If the files appear to be in different keys, the right behaviour is a warning, leaving you to transpose deliberately first.
Combining files in KeyVerse
Drop in up to twelve .mid files. KeyVerse analyses each one, showing duration, track count, note count, detected tempo and key, then lets you drag the list into the order you want — that order drives the output. Choose merge or sequence, pick your tempo policy, review the summary, rename the output and download a valid combined .mid file.
Each successful combine costs 50 coins, deducted server-side and automatically refunded if processing fails.
Frequently asked questions
- How many MIDI files can I combine at once?
- Up to twelve files per operation, within a total upload size limit, which covers virtually every arrangement.
- Will combining transpose my files?
- No. Original pitches are preserved. If the files look like they are in different keys, you get a warning so you can transpose deliberately beforehand.
- Can I control the order of the combined tracks?
- Yes. Drag the uploaded files into any order; that order determines track order when merging and section order when sequencing.