User Manual

Getting Started

Welcome to MIDISplitter 1.5

MIDISplitter is a MIDI file utility for separating tracks, combining parts, changing instruments and mix settings, adjusting pitch and tempo, and exporting repeated loops. Audition your changes using the Mac's built-in MIDI sounds before exporting MIDI copies.

Your first export

1. Choose File > Open (Command-O) and select a MIDI file, or drag one onto the drop area at the top of the main window.
2. Wait for the track list to appear. Leave all track checkboxes unchecked to work with every track.
3. Click the main Play button to listen. Click the Stop button to stop.
4. To export just one part, check that track's checkbox. Click Export 1. To separate every part, leave all checkboxes unchecked and click Split All.
5. Choose MIDI 1.0 (.mid) for broad compatibility, select the output folder, and confirm the export. The output folder opens in Finder when the split succeeds.

Keep your original

Edits are held in the current session. Export creates MIDI files; it does not save an editable MIDISplitter project. Export before clicking Remove MIDI File, opening another MIDI file, or quitting. Those actions discard the current session's edits. MIDISplitter blocks export over the loaded source file.

Choose a topic in the sidebar, or search for a word to narrow the topic list. Support & Privacy contains website and email links. MIDI Glossary is the final topic.

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Opening Files

Open a MIDI file

1. Choose File > Open, then select one .mid (Type 1 or Type 0), .midi (Type 1 or Type 0), .midi2, .smf2, or .clip file. Alternatively, drag a compatible file onto the main window's drop area.
2. The drop area shows Loading MIDI File with an animated progress bar until reading and preparation finish. A cloud-backed file may need to download first. Click Cancel Loading to discard the pending load; the file provider may continue downloading. Then read any status or compatibility message beneath the drop area.
3. Review the song name, tempo, time signature, and key information. Missing key metadata is shown as Unknown; MIDISplitter does not infer a key from the notes. SMPTE files show SMPTE timing instead of a beat-based tempo display.

You can also open an associated MIDI file from Finder or drop it onto the app icon. MIDISplitter works with one loaded MIDI file at a time; this is not a batch-opening or folder-conversion workflow. Opening another MIDI file replaces the current session, so export any changes first.

The track display

The app restores the main window's last saved position when Save App Window Positions is on in Settings. Without a saved position, or with that setting off, it opens in the center of the active display's usable area. The empty window starts with space for eight track rows. Loaded files expand or collapse the interface to fit, up to 16 visible rows, while remaining within the display. Larger files retain all their tracks and use vertical scrolling in the track list and timeline. A conductor track that contains timing rather than a musical part may not appear as a separate musical row.

Use MIDISplitter's built-in audio beat detection.

Drag a readable audio file (WAV/WAVE: .wav, .wave; AIF/AIFF: .aif, .aiff; M4A: .m4a; MP3: .mp3; CAF: .caf; or FLAC: .flac) onto the drop area to open Audio Beat Detection. The file's audio encoding must be readable by macOS. Use the drop area, not the MIDI-only File > Open dialog. Audio analysis can run without a MIDI file loaded. Load a MIDI file first if you want to apply the detected tempo to it.

Remove the current MIDI file

1. Export any edits you want to keep.
2. Click Remove MIDI File at the upper left of the main window. Playback stops and the loaded file, selections, pitch/tempo changes, and mixer edits are cleared.
3. Open another MIDI file, or reopen the original to start over. Remove MIDI File does not delete files in Finder.

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Tracks & Names

Read the track list

Each row shows a color marker, checkbox, track number, Track Name, Ch (MIDI channel), Instrument, Events count, and an audition button. Colors connect the table, timeline, and mixer. Events include more than notes: controller, program, and other MIDI messages also count.

Choose the parts to use

1. Check the boxes next to the tracks you want. A highlighted row alone is not an export selection.
2. Use the main Play button to hear the checked tracks together. The Mixer also shows the checked subset.
3. The export button labels indicate the number of tracks you will be splitting or merging. Split or Merge All uses every track when none or all are checked.
4. For a selected merge, check at least two tracks. Outside Loop mode, checking just one track still leaves Merge All available, which merges every track, not just that row.

Leaving every checkbox unchecked means all tracks, not silence. The row highlight selects a target for actions such as Control-I (instrument choice); the checkboxes choose the working subset.

Rename a track

1. Double-click the text in the Track Name column and type the new name.
2. Press Return or finish editing to commit it. Press Escape while editing to restore the prior name.
3. Choosing an instrument or drum sound replaces the track name with that sound's name, including a name you typed manually. You can rename the track again afterward. Cancel leaves the name unchanged.

Change the song's export name

1. Double-click the loaded song name in the top drop area.
2. Type a new base name and press Return. Escape cancels the edit.
3. Use Merge to create a file with this base name, or edit the suggested name in the save dialog. Separate track exports use their track names. Renaming here does not rename the source file in Finder.

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Playback & Timeline

Built-in playback and audition are supported for beat-based MIDI. SMPTE-timed files require compatible external playback software; see Formats & Timing for the editing and MIDI 1.0 export operations available in MIDISplitter 1.5.

Play, pause, and stop

1. Check a subset of tracks, or leave all boxes unchecked to hear the whole song.
2. Click the main Play button. During playback it becomes the Stop button.
3. Click the Pause button to hold the position. Click the Play button to resume. The spacebar also starts or pauses playback when the main window has focus and you are not editing text.
4. Click the Stop button to end playback. Use Return to Zero (the back-to-start transport button) to move to the song beginning.

Audition one track

1. Click the Play button at the right of a track row to audition that part by itself.
2. Use the Pause button or Stop button. To return to a group of tracks, stop auditioning, set the checkboxes, and use the main Play button.

Seek with the timeline

Drag the transport slider or the red Song Overview playhead to choose a song position. Both displays stay in sync. Stop and Pause keep the current song position. Main Play, selected-track playback, and any track's Play button continue from that position, or from a new position you choose before playing. Switching auditions also keeps the current song position. Return to Zero explicitly moves back to the start. In Loop mode, a position inside the loop is used for the first pass; later passes return to the loop start. Choosing outside the loop moves to its start. The colored timeline bars summarize MIDI event activity. Scroll vertically to inspect tracks below the first 16.

Read the Master Stereo Meter

The horizontal L and R meter above Merge and Split shows the combined MIDI activity for the tracks currently being heard. Main playback follows the checkbox selection, a track audition shows that track, and loop preview follows the tracks included in the loop. Track pan distributes activity between the left and right channels. The meter clears when playback or preview stops.

Set playback volume

Use the − VOLUME + slider beneath the Master Stereo Meter to set MIDISplitter playback volume from 0% to 100%. The slider spans the same width as the meter bars above it. It initially starts at 75% and remembers your listening level between launches unless you turn off Remember main playback volume in Settings. It applies to main playback, selected tracks, single-track auditions, and Export MIDI Loop preview. A change made during playback takes effect after you release the slider and preserves the current song position.

Playback volume changes only the temporary MIDI prepared for listening. It does not change Mixer values or any exported MIDI file. macOS system output still controls whether sound can reach your speakers or headphones. MIDISplitter cannot override system mute or a zero system volume; when either condition can be detected, the app shows a warning before playback.

What you hear

Playback uses the Mac's built-in instrument resources. Sound quality, reverb response, and program interpretation can differ from a DAW or hardware synthesizer. The Mixer meters and Master Stereo Meter show MIDI note activity shaped by the current volume, velocity, and pan settings. They do not measure audio output, loudness, or clipping.

Stop or pause before changing pitch, tempo, or mixer values. These are prepared-file settings, not live automation. Files that reuse a MIDI channel can share instrument/controller state during playback; many track rows do not mean unlimited independent sound channels.

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Pitch & Tempo

Transpose pitch

1. Stop or pause playback.
2. Enter a whole number in Pitch and press Return, or use the stepper. The range is -12 through +12 semitones: -12 is one octave down, +12 is one octave up.
3. Click the Play button to check the result, then export. Click Reset directly beneath the Pitch controls to return the offset to 0.

Pitch applies to pitched note events across the current song, including selected-track and loop output. Channel 10 percussion is not transposed. Notes shifted beyond the MIDI note range are limited to its endpoints. Displayed key metadata is adjusted when available.

Set the song tempo

1. Stop or pause playback, then click Tempo.
2. Enter the whole-number BPM in the left field and up to three decimal digits in the right field. For 123.456 BPM, enter 123 and 456. Leave the right field blank for a whole number.
3. Click OK to apply a tempo from 10.000 to 300.000 BPM, or Cancel to keep the current setting.
4. Listen again and check loop markers before exporting. Timing on the seconds display changes with tempo.
5. To remove the tempo override, click Reset directly beneath Tempo. This restores the complete tempo map from the loaded file, including its original tempo changes.

The chosen BPM scales the source tempo map relative to the song's original starting tempo. Existing tempo changes retain their relative proportions rather than becoming one constant tempo. Tempo Reset removes the override instead of approximating the original map from one BPM value. It keeps the current track selection, Pitch setting, Mixer settings, and loop markers.

Tempo changes, Tempo Reset, and Apply Tempo from audio detection are unavailable for SMPTE-timed MIDI. Pitch Reset affects pitch only; it does not reset tempo or mixer settings.

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Instruments & Drums

Choose a melodic instrument

Opening either instrument picker stops playback at the current song position. Selecting an instrument or cancelling keeps that position in both progress bars. Press any main-window Play button to continue from there; playback does not restart automatically.

1. Stop playback and click the desired track row so it is highlighted.
2. Press Control-I to open Choose Instrument. Use Control, not Command.
3. Type in Filter instruments to narrow the General MIDI list, then select an instrument.
4. Click Select (or confirm a row by double-clicking). Cancel leaves the track unchanged.
5. Audition the track, then export to keep the change. Selecting an instrument replaces the track name with the new instrument's name. You can rename the track again afterward.

Assign a drum sound

1. Highlight the track and press Control-I. An existing Channel 10 track opens Choose Drum Sound directly. For a melodic track, click Choose GM Drum Kit in the instrument picker.
2. Choose the available kit and filter the drum-sound list if needed.
3. Select the desired drum sound and click Select.
4. Audition the rhythm and export only after checking the result.

Drum assignment moves the track's channel messages to Channel 10 and maps its note events to the one selected drum note. It does not simply change the kit while retaining a multi-drum arrangement. Use it to turn a rhythmic part into one percussion sound. Reopen the original file to undo this mapping; doing so also resets other session edits.

The available drum kit is the Standard Kit. Instrument choices are General MIDI program selections, not plug-ins, SoundFont imports, or external MIDI-device routing.

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Track Mixer

Set up the mix

1. Stop or pause playback. Check the tracks you want to see, or leave all unchecked to show every track.
2. Click Mixer, or choose View > Show Mixer. Click Mixer again, choose View > Hide Mixer, or close the Mixer window to hide it. Reopening the Mixer keeps the current session's settings.
3. Drag a Vol fader to set that track's MIDI volume from 0 to 127. Zero silences it on instruments that respond to MIDI volume.
4. Move Pan left or right. C means center (64). Control-click the pan slider to center it.
5. Click Advanced Mixer to reveal Reverb and Velocity. Adjust them, then resume playback to audition the result.
6. Export the tracks or a merge to retain the mix. Closing the Mixer keeps its settings in the current session.

Restore the loaded mix

Stop or pause playback, then click Reset directly beneath Mixer in the main window. Mixer Reset restores Vol, Pan, Velocity, and Reverb to the values captured when the MIDI file was loaded. It applies to every track, including unchecked tracks and tracks beyond the visible Mixer strips. It keeps track names, instruments, notes, checkbox selection, Pitch, Tempo, and loop markers.

Advanced controls

Reverb sends MIDI CC91, with a range of 0 to 127. It requests an effect amount from the receiving synthesizer; it does not add a rendered audio effect to the MIDI file. Velocity ranges from 1 to 127 and scales note-on velocities relative to the track's original average. Relative dynamics are retained where possible, but values are limited to the MIDI range.

Large mixers and activity meters

The mixer shows up to sixteen track strips at once, or fewer on smaller screens. When more tracks are included, use the horizontal scrollbar to reach them. On a short screen, scroll vertically to reach lower controls. Settings remain attached to their tracks when strips move offscreen. The meters indicate note activity, volume, and velocity, not audio peak levels.

Playback and export behavior

Mixer controls are locked while playback is running. Stop or pause first; MIDISplitter 1.5 does not provide real-time fader automation. Current mix settings are used for prepared playback, auditions, loop previews, and exports. The app replaces source volume, pan, and reverb controller automation with the chosen mix settings in these editing paths. Check output in your destination instrument if the source contains automation.

A MIDI channel carries shared controller and program state. Multiple tracks using the same channel can interact, especially with large files or several drum parts. Splitting parts into separate files and assigning separate destinations in your DAW avoids assuming that 128 tracks provide 128 independent MIDI 1.0 channels.

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Split, Merge & Reports

Split all tracks into separate MIDI files

1. Load a MIDI file.
2. Leave all checkboxes unchecked, or check every track. Click Split All.
3. Choose MIDI 1.0 (.mid) or MIDI 2.0 (.midi2). Read Formats & Timing before choosing MIDI 2.0 for an unfamiliar destination.
4. Use Choose Folder in the export window to select a writable destination. Check Save Text Report if you want a report. Its initial state follows Save text reports by default in Settings, which starts off.
5. Click Split All Here. If existing output filenames are listed, choose Replace only when you intend to replace those output files; otherwise cancel and choose a different folder.
6. Wait for the success message. Finder opens the destination folder. Import the separate MIDI files into your DAW or another MIDI application.

Export only selected parts

1. Check the boxes next to the desired tracks. With a proper subset selected, the button changes to Export N, where N is the number checked.
2. Click Export N, choose the format and folder, and confirm with Export Here.
3. Expect one MIDI Stem file per chosen track, not one combined file.

Merge parts into one MIDI file

1. To merge all tracks, leave all boxes unchecked. To merge a subset, check at least two tracks.
2. Click Merge All or Merge N, then choose the output format.
3. Choose a filename and destination in the save dialog. The suggested name uses the song base name with _merged appended.
4. Optionally check Save Text Report, then click Save. Finder reveals the merged file after a successful export.

Merge combines musical parts from the currently loaded file; it does not concatenate several songs or open multiple source files. Standard MIDI merged output combines the selected musical events into a merged track. Channel assignments may be adjusted to separate parts where MIDI 1.0 channel capacity permits. Recheck instruments and drums in the destination application.

Names, reports, and file safety

Split filenames are derived from track names, with disambiguation where needed. Loop filenames include _loopx followed by the repeat count. The song name in the drop area supplies the default merged filename. Unsafe filename characters are sanitized.

Save Text Report writes a human-readable summary alongside the export. Split operations use MIDISplitter_export_report.txt in the destination folder; merged exports use a report beside the merged file. Use a fresh folder to keep reports from separate runs distinct. If macOS asks for permission to save a merged report, select the export folder. A report-write failure does not necessarily mean the MIDI export failed: read the status message and inspect the output.

Export refuses to overwrite the loaded source MIDI file. Existing output files can still be replaced after confirmation, so keep valuable earlier exports in separate folders. A successful export saves your current choices in the MIDI output, not as a reopenable MIDISplitter editing session.

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Loop Preview & Export

Choose a loop section

1. Load a MIDI file and choose the track checkboxes. Leave all unchecked to include every track.
2. Click Loop in the main window to enable the loop markers.
3. Drag the start and end markers on the timeline around the desired passage. Click the Play button to audition the section.
4. Stop playback, then choose Split Loop for separate files or Merge Loop for one combined file. Merge Loop needs at least two included tracks; it is disabled when exactly one track is checked.

Refine the range in Export MIDI Loop

1. Read Start, End, and Length in the loop export window. The L/R LED meter at the upper left shows the same stereo MIDI activity as the main window during preview; it clears when preview is paused or stopped. The preview shows only the tracks included in the export, using your main-window checkbox selection. Leave all checkboxes unchecked to include every track. Scroll vertically to see additional tracks; the ruler and loop markers stay visible.
2. Drag a marker to refine the range. Markers snap to the displayed grid boundaries. Beat-based files initially align the export range to bars; SMPTE files use time-based boundaries. Always check the displayed final times.
3. Click the preview Play button to listen. The Pause button holds preview position; the Play button resumes it. Click the Stop button to stop. Space also controls preview when you are not editing a field.
4. Enter a repeat count from 1 to 999, or use the stepper. This controls the number of times the selected loop repeats in the exported MIDI file.
5. Click Split Loop or Merge Loop to accept the refined range; the label matches the action you chose in the main window. Then choose the MIDI format and destination and finish the export. Cancel closes the loop options without exporting.

Four-cycle preview

The export-window preview prepares four consecutive repetitions in memory. The playhead wraps visually at each loop boundary. After four cycles, the prepared sequence restarts and a brief pause may occur. This restart is a preview behavior, not silence inserted between the internal exported repetitions.

Changing a marker during preview rebuilds the audition; a short interruption at that edit is expected. Split Loop or Merge Loop also updates the main window's loop markers to the accepted range. If you cancel a later format or destination dialog, those accepted marker adjustments remain.

Check musical boundaries

Loop export rebases the section to the beginning of the output and repeats it the requested number of times. Notes crossing the end boundary are ended there to prevent hanging notes. A note that began before the start marker is not necessarily retriggered as a new attack. Choose boundaries around note starts and listen for clipped sustained notes, pickup notes, rests, and effect tails.

To change the included tracks or mixer values, cancel the loop options, make the changes in the main window, and reopen the loop export. For the whole song again, turn Loop off before splitting or merging. The export window shows up to sixteen readable track lanes at once, with fewer on short screens. Scrolling does not change the included tracks, loop range, or repeat count.

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Audio Beat Detection

Estimate an audio recording's tempo

1. If you intend to apply the result to a MIDI song, open that MIDI file first. You can also analyze audio with no MIDI file loaded.
2. Drag a readable WAV/WAVE, AIF/AIFF, M4A, MP3, CAF, or FLAC audio file supported by macOS onto the main drop area.
3. Wait for Audio Beat Detection to finish. The window shows the file, length, waveform, selected BPM, estimated beat count, and detection notes.
4. Review the tempo candidates instead of assuming the first value is correct. Select another candidate when it better matches the musical pulse.
5. Use 1/2, 2/3, 3/2, or 2x to correct a half-time, double-time, or related tempo interpretation. Alternatively, enter a known BPM and press Return or click Use BPM.
6. Click Apply Tempo to set the loaded MIDI song's tempo, or OK to close without applying it.

Interpreting the result

Beat detection estimates a pulse; it does not guarantee the correct musical meter, downbeat, or tempo for recordings with changing tempo. Sparse, rubato, syncopated, or noisy material can yield ambiguous candidates. The estimated beat count depends on the selected BPM and recording length; it is not a count of detected MIDI note events.

Use BPM selects a value in the analysis window. Apply Tempo is the separate step that changes the MIDI song. Values are limited to 10 through 300 BPM. Apply Tempo is unavailable without a loaded beat-based MIDI file and is disabled for SMPTE MIDI.

Analysis scope and cancellation

The Beat Detection window shows a loading indicator while the audio is opened and analyzed. For an iCloud file that needs downloading or updating, it shows Loading Audio from Cloud. You can keep using the app or close the window to cancel its loading and analysis. Dropping another audio file replaces the pending analysis. macOS may continue a cloud download after you close the window. If loading fails or the cloud wait exceeds two minutes, check your internet connection, download the file in Finder, and drop it again; you can also try a local copy.

MIDISplitter reads the full recording for analysis. Beat detection accepts up to 256 MiB of decoded mono samples: about 25.4 minutes at 44.1 kHz, 23.3 minutes at 48 kHz, or 11.7 minutes at 96 kHz. This limit is based on decoded audio, not compressed file size; decoding and analysis need additional memory. Oversized recordings produce an error with no partial tempo result. Choose a shorter audio file or a lower-sample-rate copy. Close the analysis window to cancel a running analysis.

The waveform is an analysis display, not an audio editor or an audio-to-MIDI transcription tool. Applying a tempo changes the MIDI timing; it does not stretch, edit, export, or overwrite the dropped audio file.

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Formats & Timing

Choose a compatible output

1. Use MIDI 1.0 (.mid) when your destination expects a Standard MIDI File. Check the destination application's import documentation before selecting MIDI 2.0.
2. Use MIDI 2.0 (.midi2) only with a destination that accepts the MIDI Clip/SMF2CLIP container. MIDI 2.0 device support alone does not guarantee file-container support.
3. For unusual files, enable Save Text Report, inspect any conversion warnings, and reopen the exported copy in the destination software before relying on it.

Standard MIDI Files

MIDISplitter accepts Format 0 and Format 1. Format 0 stores its events in one track chunk; Format 1 stores simultaneous tracks. The app presents musical parts for its track operations. Format 2 contains independent sequences and is rejected; export each sequence from another application as a separate Format 0 or Format 1 file first.

MIDI 2.0 scope

MIDISplitter imports supported MIDI Clip files with .midi2, .smf2, or .clip extensions and exports .midi2 clips. Its editable working state uses MIDI 1.0-resolution values. Eligible unmodified native MIDI 2.0 packets can be retained in supported exact-match export paths; edits, selection changes, mixing, or loop operations can make that preservation ineligible. Do not assume every MIDI 2.0 feature round-trips unchanged.

Unsupported packet families and some metadata are skipped or reported rather than fully editable. Full per-note expression, SysEx8, MIDI-CI Profiles/Property Exchange, and live UMP input/output are not offered. Some structurally valid files are rejected when their timing cannot be represented safely in the app's working format.

Beat-based and SMPTE timing

Most MIDI files use ticks per quarter note (PPQN) plus a tempo map to determine elapsed seconds. SMPTE timing instead uses frames per second and ticks per frame. MIDISplitter treats SMPTE editing as time-based: tempo changes are unavailable and MIDI 2.0 export is blocked.

Built-in SMPTE playback is not supported in MIDISplitter 1.5, including whole-song playback, selected-track or single-track audition, and Export MIDI Loop preview. SMPTE files can still be read, edited in time, split, merged, and exported with loop repeats as MIDI 1.0 (.mid), preserving their frame-based timing. Tempo changes and MIDI 2.0 export remain unavailable. Listen to the exported files and verify timing in compatible external software.

Representation limits

Extreme tempos, timing resolutions, silent gaps, or file sizes may exceed MIDI format limits and produce an error instead of an export. MIDISplitter does not silently promise an exact conversion for values the target representation cannot hold. A MIDI 2.0 file is not the same thing as a MIDI 1.0 Format 2 file.

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Settings

Open Settings

Choose MIDISplitter Settings… beneath About in the application menu, or press Command-comma. Changes are saved automatically and remain in effect between launches. Close the Settings window when finished.

Show MIDI 2.0 import dialogs — On by default

Turn this off to skip the import report popup when loading MIDI 2.0 files. The import summary and unsupported-packet count still appear in the main window's status message. File-loading errors still appear. This setting changes only the popup; it does not change MIDI compatibility, conversion, or file contents.

Remember main playback volume — On by default

Restore your most recent main playback volume when you reopen the app, including a level of 0%. Turn this off to start future launches at 75%. Switching it off leaves the current session's volume unchanged and forgets the saved level. Switching it on remembers the current level immediately. It affects listening only, including track auditions and loop preview; exported MIDI and Mixer settings are unchanged.

Save text reports by default — Off by default

Turn this on to preselect Save Text Report each time you open a split or merge destination window, for either MIDI format and for whole-song or loop exports. You may check or uncheck it for that individual export. That choice does not change the Settings default. Changes to the default apply to newly opened destination windows.

Save App Window Positions — On by default

Reopen the main window, Mixer, Audio Beat Detection, User Manual, Settings, and app-owned export/prompt windows where you last dragged them. Restored windows stay within the available displays. Turn this off to use default positions when windows reopen; the main window centers at launch. Open windows do not jump when you change this setting. Previously saved positions are kept while off and used again when you turn it on. Window sizes still follow their existing layout rules. macOS Open and Save dialogs and the standard About panel retain system-managed placement.

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Troubleshooting

A file will not open

1. Read the status message. Confirm the file is a readable Format 0/1 MIDI or supported MIDI Clip, not a Format 2 sequence collection or a renamed audio file.
2. For cloud or external storage, make the file locally available and select it again. Use the drop area for audio analysis.
3. Try a known-good small MIDI file. If only one file fails, send Support the error and a shareable example. Do not overwrite the original while investigating.

Playback is silent or fails

1. Check the Playback Volume slider beneath the Master Stereo Meter, then check the Mac's output device, mute state, and system volume. MIDISplitter warns when it can detect that system output is muted or set to zero, but it cannot override that setting. Confirm the chosen tracks contain notes at the current position.
2. Stop playback, check the Vol and Velocity values, and audition one track from its beginning.
3. Read any playback error. SMPTE playback is unsupported in 1.5; export as MIDI 1.0 and listen in compatible software. Missing built-in instrument resources can also prevent playback. A moving activity meter is not proof of audible output.
4. Test a MIDI export in another compatible player. Sounds and reverb can differ between synthesizers.

The wrong tracks were exported

Use checkboxes, not just a highlighted row. No checked boxes means all tracks. Export N creates separate files; Merge N combines at least two checked tracks. Outside Loop mode, Merge All still uses all tracks when only one is checked. Check whether Loop is enabled if the output contains only a section.

A control cannot be changed

Stop or pause playback before editing pitch, tempo, or mix values. Load a MIDI file before using its editing controls. Tempo and MIDI 2.0 export are unavailable for SMPTE files. Apply Tempo in audio analysis also requires a loaded beat-based MIDI file.

A loop has a gap or a cut-off note

Check whether the pause occurs only after four export-preview cycles; that prepared-batch restart is expected. A gap within the passage can be source silence or an unsuitable boundary. Refine the start/end markers and compare an exported two-or-more-repeat MIDI file. Sustained notes crossing a boundary are ended to avoid stuck notes.

Saving or report creation fails

Choose a writable output folder with enough disk space. Do not choose the loaded source as the destination. For a requested text report, grant access to the export folder when asked. Inspect Finder and the status message: the MIDI may have saved even if its report could not be written.

The app is busy with a large file

Opening another MIDI file or replacing a playback request cancels obsolete preparation. Loop preview prepares in the background; press Stop or close the loop window to cancel. Scroll to reach tracks beyond the visible rows. MIDI source files are limited to 64 MiB and one million decoded events or UMP packets. Export also checks estimated working memory, event expansion and generated size; reduce the selection or loop repeats if the memory-budget message appears. Nothing is silently truncated. Close Audio Beat Detection to cancel analysis. If its 256 MiB decoded-audio limit is exceeded, use a shorter audio file or a lower-sample-rate copy. For support, record the file length, sample rate, and track count, not just its compressed size.

Restore the original settings

Use the three Reset buttons in the main window to restore one group of settings at a time. Pitch Reset returns transposition to 0. Tempo Reset removes the tempo override and restores the complete tempo map from the loaded file. Mixer Reset restores every track's loaded Vol, Pan, Velocity, and Reverb values, including tracks that are unchecked or offscreen. These controls do not undo track names, instrument or drum assignments, checkbox selections, or loop markers.

To discard every session edit, reopen the original MIDI file or click Remove MIDI File and load it again. Export any wanted changes first: there is no project save or general undo history for restoring an earlier session.

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Support & Privacy

New Toy Software Support

Visit the support page for help with MIDISplitter, or email New Toy Software directly.

Support Website

contact@newtoysoftware.com

Ask a question or report a problem

1. Choose MIDI Splitter > About MIDI Splitter and note the version and build number.
2. Include your macOS version, the operation you were performing, the exact message shown, and the steps needed to reproduce the problem.
3. For file-specific issues, include the file format, track count, and a screenshot or export text report when useful. Share a small example MIDI/audio file only if you have permission to share it.

The email link opens a new message in your configured mail app. It does not send a message or attach your files automatically.

Privacy Policy

Read New Toy Software's privacy policy on the website. The manual is bundled with MIDISplitter and can be read offline; website links open in your browser and require an internet connection.

Privacy Policy

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MIDI Glossary

These terms describe the MIDI files, controls, and operations used in MIDISplitter 1.5.

Activity meter

An LED-style display driven by MIDI note activity and the current mix settings. Track meters are vertical; the main-window Master Stereo Meter is horizontal and shows left and right activity. These meters do not measure rendered audio or clipping.

Audition

Listening to a part or selected group before committing to an export. Audition playback does not create an audio file.

Bar / measure

A group of beats defined by a time signature. In 4/4, a bar contains four quarter-note beats. The loop export view uses a musical grid for beat-based MIDI.

Beat / BPM

A beat is a recurring pulse. BPM means beats per minute; MIDI tempo is expressed relative to quarter notes. Audio beat detection estimates a musical pulse, which may need half-time or double-time correction.

Channel

One of 16 MIDI 1.0 message addresses, displayed as Channels 1-16. A channel is not a track: several tracks can send messages on the same channel and share sound settings. Channel 10 conventionally carries General MIDI percussion.

Clip / SMF2CLIP

The MIDI Clip file container for Universal MIDI Packets supported by MIDISplitter's MIDI 2.0 import/export. Its file support is distinct from a synthesizer's live MIDI 2.0 support.

Conductor track

A track that carries song-level information such as tempo and time signature rather than a musical instrument part. It can be retained in file processing without appearing as an instrument row.

Control Change / CC

A MIDI message that changes a channel setting. MIDISplitter's mixer uses CC7 for volume, CC10 for pan, and CC91 for reverb amount. The receiving instrument decides how supported controllers sound.

DAW

Digital Audio Workstation: a music-production application that can sequence MIDI, host instruments, and record or edit audio. MIDISplitter prepares MIDI files for such tools rather than replacing them.

Delta time / Delta Clockstamp

An interval between events or packet positions. Standard MIDI Files encode delta times in ticks; MIDI Clips use Delta Clockstamp messages to advance the packet timeline.

Drum note / drum kit

In General MIDI percussion, note numbers choose individual sounds, such as kick or snare, rather than ordinary melodic pitches. A kit is a set of percussion sounds. MIDISplitter's drum assignment maps a track to one chosen sound on Channel 10.

Event

A timed instruction in a MIDI file, such as a note-on, note-off, controller change, program change, or metadata message. The Events column is not simply a note count.

Export / split / merge

Export writes an output copy. Split produces a separate MIDI file for each included part. Merge combines included parts from the loaded song into one MIDI file. Neither operation renders recorded audio.

Flex Data

A UMP message family used for information such as tempo, time signature, and certain text metadata. Support for one Flex Data message does not imply support for every metadata type.

Format 0 / Format 1 / Format 2

Three Standard MIDI File organizations. Format 0 uses one track chunk; Format 1 uses simultaneous track chunks; Format 2 contains independent sequences. MIDISplitter accepts Formats 0 and 1 and rejects Format 2. Format 2 is not MIDI 2.0.

General MIDI / GM

A convention for instrument program names and percussion mapping, helping a MIDI arrangement use recognizable instrument families on different synthesizers. It does not guarantee identical sound samples.

Group

A UMP address that distinguishes sets of MIDI channels. Group and channel together can identify parts in MIDI Clip input. Imported Group identity does not turn the app's built-in player into an unlimited multi-port synthesizer.

Key signature

Metadata naming a musical key. MIDISplitter displays and transposes available key information; Unknown means usable key metadata was not found, not that the music has no key.

Loop / repeat count

A selected time range played or exported repeatedly. Repeat count is the number of consecutive copies written to loop output, from 1 to 999. Export preview uses its own four-cycle preparation batch.

MIDI 1.0 / MIDI 2.0

Generations of the Musical Instrument Digital Interface standard. MIDI describes performance and control data, not recorded sound. MIDI 2.0 introduces higher-resolution messages and other capabilities; MIDISplitter supports a defined subset through MIDI Clip files.

Note-on / note-off

Messages that begin and end a note. A MIDI 1.0 note-on with velocity zero also means note-off. Missing note endings can cause stuck notes; loop export adds endings where needed at boundaries.

Pan

The requested left/right position of a channel. MIDISplitter uses MIDI values 0-127, with 64 displayed as C for center.

PPQN / TPQ / tick

PPQN means pulses per quarter note; TPQ means ticks per quarter note. A tick is a timing unit, not a fixed number of milliseconds in beat-based MIDI. PPQN and the tempo map together determine seconds.

Program Change

A channel message selecting an instrument program. User-facing General MIDI instrument lists commonly number programs 1-128, while the underlying MIDI values are 0-127.

Reverb

A reverberation effect that simulates sound reflections. The mixer sends a requested reverb amount as MIDI data; the receiving synthesizer must provide the effect.

Semitone / octave / transpose

A semitone is one chromatic pitch step; an octave spans 12 semitones. Transposition shifts pitched notes by an offset. MIDISplitter allows -12 to +12 and excludes Channel 10 percussion.

SMF

Standard MIDI File, usually named with .mid or .midi. It stores timed MIDI events and metadata. SMF Format 2 must not be confused with the MIDI 2.0 Clip format.

SMPTE timing

Frame-based timing specified as frames per second and ticks per frame. MIDI supports codes for 24, 25, 29.97 drop-frame, and 30 fps; the -29 code uses a 30000/1001 rate. MIDISplitter keeps these files time-based and disables tempo changes and MIDI 2.0 export.

SysEx / MIDI-CI

System Exclusive messages carry device-specific data. MIDI Capability Inquiry lets devices discover and negotiate capabilities. These terms can appear in compatibility reports; MIDISplitter is not a device-configuration or live MIDI-CI tool.

Tempo map / time signature

A tempo map records changes in quarter-note duration over a song. A time signature describes beats per bar and the note value used for a beat. Setting Tempo in MIDISplitter scales the original map relative to its starting BPM, preserving relative tempo changes; it does not edit the time signature.

Track

A collection of timed events, often representing an instrument part. Track count, channel count, and the number of audible instruments need not match. MIDISplitter lists musical tracks for selection, editing, audition, and export.

UMP

Universal MIDI Packet, a packet representation that can carry MIDI 1.0 and MIDI 2.0 messages as well as other message families. A UMP-based file can therefore contain MIDI 1.0-resolution events.

Velocity / volume

Velocity describes an individual note's attack strength and can affect both loudness and timbre. Volume is a channel-level setting. MIDISplitter's Velocity control scales note-on values; Vol sends a channel volume controller. The main Playback Volume slider attenuates temporary listening data without changing Mixer values or exported files.

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