Why Does My MIDI Show C3 in One App and C4 in Another?
The note-name label may use a different octave-numbering convention. MIDI note number 60 is middle C, but software and hardware can label that same note C3, C4, or C5. Compare the MIDI note number before assuming your conversion moved the note by an octave.
Check the note number first
Open the MIDI clip in a piano roll or event list and inspect the numeric pitch value, if your app shows one. If two apps display different names but both identify the event as MIDI note 60, they are naming the same MIDI note differently. The MIDI Association explains that MIDI identifies middle C as note number 60 while octave labels can vary; its note-number table also shows note 72 as C one octave above note 60.
This is a display convention, not proof that the converter changed the audio pitch. Novation documents a case where its controller display calls a note C3 while FL Studio displays the same middle-C MIDI note as C5. Apple’s Logic Pro documentation likewise describes middle C as note 60 and says the displayed octave name can be changed to match the connected device.
Tell a label difference from a real octave shift
- Select one note in the MIDI editor and record its MIDI note number.
- Open the same MIDI file in the other app and inspect that note again.
- If the number is unchanged, the different C-number label is an octave-naming convention.
- If the number differs by 12, the MIDI event is one octave apart in the standard 12-semitone note map. Check whether the file was transposed, whether you selected the matching note, and whether an instrument or track has an octave or transpose setting.
The number comparison is more reliable than comparing the text label alone. Also listen to the note through the same instrument and settings in both apps. A patch can have its own transpose or tuning behavior, so a label by itself cannot prove what frequency you hear.
Set a consistent display if you prefer
Some applications let you choose how middle C is displayed. Logic Pro, for example, provides a “Display Middle C As” setting. Pick the convention that matches your keyboard or workflow, then keep it consistent when reading note names. This is a display preference; the inference is that changing it changes the label shown by the editor, not the MIDI note number stored in the file.
What this means after an audio-to-MIDI conversion
When you review an exported MIDI file, do not change every note just because one editor calls a note C3 and another calls it C4. First compare the MIDI note number or audition the same event under the same instrument settings. If the number is actually 12 steps higher or lower, investigate a real transposition or note-detection issue; if the number is identical, changing the octave label is enough.
This guide explains MIDI note naming only. It does not claim that AudioNote MIDI detects every source pitch correctly; compare the exported notes with the recording before using them in an arrangement.
Sources and scope
- The MIDI Association: MIDI Octave and Note Numbering Standard
- The MIDI Association: Why 12 Notes?
- Apple Support: Note events in Logic Pro
- Novation Support: FLkey MIDI note and octave numbering standards
The sources support the note-numbering explanation. They do not establish how every DAW labels every note, or diagnose a particular MIDI file without inspecting its events.