Flex Pitch and pitch correction in Logic Pro (the built-in autotune)

Platform and version

Tune a vocal with Flex Pitch, then with Pitch Correction

Both tools are part of Logic Pro; nothing extra is needed. The button, menu and parameter names below are taken from Apple's Logic Pro User Guide pages listed under Sources.

Method 1: Flex Pitch (edit each note)

Flex Pitch analyzes a monophonic recording into notes you can move, like MIDI. Apple's guide states that pitch quantizing is accurate only on monophonic regions, so use it on a lead vocal, a bass line or a single-note instrument, not on chords.

1. Open the Audio Track Editor. Select the vocal track and choose View > Show Editors, click the Editors button, or double-click the audio region.
2. Turn Flex on. Click the Show/Hide Flex button in the Audio Track Editor menu bar (or press Command-F with the editor focused). If flex is not yet enabled on the track, a dialog asks whether to turn it on.
3. Choose Flex Pitch. Open the Flex Mode pop-up menu next to the button and choose Flex Pitch. Logic analyzes the region and draws each detected note as a bar on a piano-roll grid. (In the Tracks area the same choice lives in the Flex pop-up menu that appears in the track header after you choose Edit > Show Flex Pitch/Time.)
4. Correct everything in one move first. Select all notes (Command-A) and drag the Pitch Correction slider in the editor inspector to the right. At 100 percent every note snaps to the nearest chromatic pitch; around 50 to 70 percent is usually enough for a natural result. To snap to the song's key instead of the chromatic scale, choose a key and major or minor from the Scale Quantize pop-up menus.
5. Fix individual notes. Drag a note bar up or down to change its pitch; drag it left or right to move it; drag an edge to resize; click with the Scissors tool to split; select two notes and press Command-J to join.
6. Use the six hotspots for detail. Each note bar has hotspots you drag vertically. Apple's guide lists them as: upper-left for pitch drift at the start, upper-middle for vibrato, upper-right for pitch drift at the end, lower-left for gain, lower-middle for fine pitch, lower-right for formant shift. Reducing pitch drift at the start of a note removes the scoop into the pitch; reducing vibrato then adding back a little is how over-corrected vocals get their life back.
7. Tighten timing if needed. With Flex Pitch active, the editor also offers a Time Quantize pop-up menu and a Strength slider for the selected regions, so you can nudge timing without switching to a Flex Time algorithm.
8. Check the region's Flex & Follow setting. In the Region inspector, the Flex & Follow pop-up menu must be On (or one of the Align options) for flex edits to play back. Off disables flex for that region while keeping your edits stored.

Method 2: the Pitch Correction plug-in (real time)

1. Insert it. On the vocal channel strip click an Audio Effect slot and choose Pitch > Pitch Correction. Put it before compression and reverb so it sees a clean signal.
2. Set the key. Choose the song's key from the Root pop-up menu and a grid from the Scale pop-up menu. Apple's guide describes Scale as the pitch quantization grid that off-pitch notes are pulled toward and notes that setting the right key may be all a decent performance needs. Chromatic is the safest default when you are unsure; Major or Minor is tighter.
3. Exclude notes you do not want corrected. Click keys on the plug-in keyboard to drop those notes from the grid, or use the per-note Bypass buttons. This keeps a blue note or a deliberate slide intact.
4. Set Response. The Response slider controls how quickly the voice is pulled to the corrected pitch. Slow values are transparent; the fastest values produce the stepped, hard-tuned effect.
5. Set the detection range. Apple's parameters page describes Normal and Low range buttons for the pitch range that is scanned; use Low for bass voices and instruments. A third-party guide for Logic Pro 12.3 describes a Neural Pitch Detection option that is on by default and takes over this choice, with the manual range appearing when it is turned off; Apple's own parameters page predates that option, so treat the exact label as something to confirm in your version.
6. Tuning reference. Leave Use Global Tuning on so the correction follows the project's tuning settings; turn it off and set Ref. Pitch in cents only to match an instrument that is deliberately off A440.
7. Compare. Use Bypass All to A/B the original and corrected signal, and watch the Correction Amount display: large constant corrections mean the key is wrong.
8. Automate if the song modulates. Apple notes that both Scale and Root can be automated, so a key change mid-song can be followed.

When to use which

• Natural, invisible tuning of a good take: Flex Pitch with the Pitch Correction slider at 50 to 80 percent, then hand-fix two or three notes.
• The hard-tuned, stepped effect: Pitch Correction plug-in, Scale set to the key, Response fast.
• Quick demo pass or live tracking: Pitch Correction plug-in, because it costs nothing in editing time and can be removed later.
• Harmonies, doubles, stacked vocals: Flex Pitch each part so they agree, then a light Pitch Correction pass if the style wants it.
• Polyphonic parts (guitar chords, piano): Neither is designed for it. Flex Pitch is monophonic by Apple's description; re-record or use a third-party polyphonic editor.

Logic Pro 12 is described by Apple and reviewers as adding machine-learning features across the app. For Pitch Correction, the only ML-related change this page can source is the Neural Pitch Detection option described above; this page does not claim more than that.

Settings that decide how natural it sounds

After tuning

Listen to the tuned vocal solo and then in the mix. Tuning that sounds obvious solo often disappears in context, and tuning that is invisible solo can reveal flat notes once the harmony is playing. If you used Flex Pitch, bounce the track in place (File > Bounce > Track in Place) when you are happy, so the project no longer re-renders the flex analysis on every play; the bounce page covers the options. Flex analysis on many tracks is also a common cause of the alerts covered on Logic Pro system overload.

Tuning comes before the rest of the vocal chain. Once the notes are right, move on to compression, EQ and space, then the final pass on Mastering in Logic Pro.