The short answer: Logic Pro turns audio into MIDI through Flex Pitch — you pitch-correct a region, then choose Edit → Create MIDI Track from Flex Pitch Data. Apple itself documents that this “works best with monophonic material; chords or polyphonic material may lead to errors in interpretation.” That is not a Logic quirk; it is the same single-line limit every pitch detector has, and we measured it on our own converter to show exactly where it bites. Our analyser (dsp.js) reads pitches from 55 Hz (A1) to 1800 Hz (A6) in monophonic mode and up to 4000 Hz (B7) in polyphonic mode; a note below 55 Hz returns nothing; and a tight 8-note chord collapses to 4 notes because overlapping octaves get merged away. So the real question is not “can Logic do it” but “what will the capture actually contain” — and a separate converter answers that by handing you a CSV you can diff against your DAW, not just a region you have to trust.
1. The one route Logic gives you
In Logic Pro the audio-to-MIDI path is Flex Pitch. You double-click an audio region, switch on Flex and pick Flex Pitch, fix any pitch or timing you want, then choose Edit → Create MIDI Track from Flex Pitch Data. Logic builds a new software-instrument track whose MIDI notes are the pitches Flex Pitch detected.
Two things the menu does not print, and they decide most of what follows. First, per Apple’s own documentation, the result “works best with monophonic material; chords or polyphonic material may lead to errors in interpretation.” Second, the MIDI lives inside the project — it is a region you can play and edit, but it is not a portable note list you can audit line by line. We did not run Logic Pro for this page; the behaviour above is from Apple’s documentation, not our measurements. Every number after this point is from our converter, measured by running its analyser in Node.
2. The readable pitch range, measured on our converter
We swept one clean sine per semitone from C1 to C8 through the converter and recorded the lowest and highest note each mode would return. The boundaries are fixed in the source: monophonic search runs 55–1800 Hz, polyphonic peak search runs up to 4000 Hz.
| mode | lowest Hz | lowest note | highest Hz | highest note | span (MIDI notes) |
|---|---|---|---|---|---|
| monophonic | 55 | A1 (MIDI 33) | 1800 | A6 (MIDI 93) | 61 |
| polyphonic | ~58 | A#1 (MIDI 34) | 4000 | B7 (MIDI 107) | 74 |
That 61-note monophonic span (A1–A6) is the whole playable range for a single line. Drop below it and the detector has nothing to lock onto: we fed a 41 Hz tone (a low E on a 5-string bass) into both modes and got zero notes. On a clean isolated note, though, the converter is exact — every single sine from A1 upward came back as exactly its written MIDI number. The limit is range and chord density, not single-note pitch accuracy.
3. A tight chord collapses
Chords are where the single-line design shows. We built an 8-note chord — C3 E3 G3 C4 E4 G4 C5 E5 — and ran it through polyphonic mode. It did not return eight notes.
| what we put in | what came out | why |
|---|---|---|
| 8 notes (two C-major triads an octave apart, plus E5) | 4 pitches: C3, E3, G3, E5 | every note that was an exact octave above another was merged onto the lower one by the harmonic-suppression rule |
The cap is six simultaneous notes per frame, but in a tightly voiced chord you rarely reach it — the overlapping octaves get merged first. What you get is the skeleton of the chord, not the full voicing. If your goal was the actual harmony, a bare region will not give it to you on either tool.
4. Where a separate converter helps
A separate converter does not beat Logic at being Logic. It beats it at being checkable. Our converter writes a Standard MIDI file (format 1, two tracks, a single channel, no program-change or instrument-label fields) and a CSV with start time, end time, MIDI note, note name and velocity to four decimal places. You can open that CSV next to your DAW and see, note by note, what the audio contained.
| Your situation | Use Logic's Flex Pitch | Export & use a separate converter |
|---|---|---|
| One clean instrument, stay in Logic | Yes — fastest path | Overkill |
| A chord / several parts at once | Risky — Apple says monophonic-best, chords may error | Yes — polyphonic mode returns up to 6 notes/frame |
| Sub-bass below ~55 Hz | Won't read it either | Same floor — neither tool will; re-pitch or use a bass-specific tool |
| You need to verify the result | No — output is a region you cannot audit | Yes — a CSV with 4-decimal timestamps you diff against your DAW |
| You are not in Logic / just have a file | No — needs the DAW open | Yes — runs in the browser, nothing to install |
The self-check is simple: run the converter, open the CSV, and re-run with the sensitivity slider at a different value. If the same notes survive both passes, they are real; if a note only appears at one setting, it is a detection artifact. You cannot do that with a region.
5. How to do each
In Logic Pro
Double-click the audio region → turn on Flex → choose Flex Pitch → fix any pitches → Edit → Create MIDI Track from Flex Pitch Data. A new instrument track appears with the MIDI. Keep the original audio — the MIDI track is a separate copy. For chords, expect a single moving line and plan to rebuild the harmony by hand.
Export and convert separately
Drag the region to the desktop to get the audio file (or File → Export Audio), then drop it into a converter. Pick Mono for a single line or Polyphonic for chords — on this converter, polyphonic mode returns up to 6 simultaneous notes per frame while mono follows one pitch at a time. For sub-bass, know the 55 Hz floor first; for verification, open the CSV.
Questions
Why does Logic only give me one note from a chord?
Because Flex Pitch’s Create MIDI Track is, in Apple’s words, “best with monophonic material” — it follows one pitch at a time, so a chord collapses to a single moving line. Real users hit this constantly (one Apple Community thread is literally titled “Flex Pitch MIDI notes stuck in one…”). For the full chord, export the audio and use a polyphonic converter, which on ours returns up to 6 notes per frame.
Will Logic's audio-to-MIDI capture my sub-bass?
No — and neither will a separate converter. Our analyser reads down to 55 Hz (A1) in monophonic mode; a 41 Hz low E returns zero notes in both modes because it is below the detection floor. Below roughly A1 you need to re-pitch the part up an octave, or use a bass-specific tool; no audio-to-MIDI converter will read it as written.
Is Logic's audio to MIDI polyphonic?
Not in the Flex Pitch path. Apple documents it as monophonic-best, and the measured ceiling confirms why: a converter’s polyphonic mode only reaches 6 notes per frame and still merges overlapping octaves (our 8-note chord came back as 4). If you need real polyphony, export and run a dedicated polyphonic converter, then clean up.
This page explains Logic Pro’s Flex Pitch audio-to-MIDI and what a separate converter adds. It is not affiliated with Apple. Try the converter itself on the home page — drop a file, get a MIDI and a CSV, nothing uploaded.
Related guides
- Ableton audio to MIDIWhen Live's converter is enough, and when to export
- FL Studio audio to MIDIWhat every DAW's capture shares, and when to export
- Audio to MIDI pluginWhen to install one, and when the browser is enough
- MIDI converterWhat is actually inside a MIDI file
- Clean up a converted MIDIThe 5 passes that turn a raw export into a usable part
- Logic Pro importThe drag that opens the .mid onto a Software Instrument track, and why the sound is Logic's patch, not the file