Drop it on the vocal. Auto key. Never a wrong note. $15 · Standalone app, VST3 and AU on macOS (Apple Silicon and Intel); VST3 on Windows (64-bit).
Backing vocals without picking a scale. Drop KORO on the lead and it listens while the singer sings, reading the key and scale as it goes. Until it is sure, it plays safe: a plain unison double, or the fifth. Thirds come in only on notes where every likely key agrees, so the harmony never lands on a wrong note. A tight double, a stack or a whole choir behind the voice, and you never open a scale menu.
A close vocal double. Doubling alone needs no key.
Drop it on a vocal. Let the key read-out settle while the singer sings, or press LOCK once you like the key. Pick a mood. That is the whole workflow.
Pick a mood by ear and KORO keeps it in key: Tight Double to thicken a lead, Backing Stack and Choir to put voices behind it, Third and Fifth for a single harmony line, and Arabesk Choir.
Fifths and octaves are consonant in every key, so KORO plays them whenever a note is clearly sung. A third depends on the key, so KORO plays one only on a note where every key it still considers likely agrees; otherwise that voice falls back to a plain unison double, or to the fifth. The key is read from the audio continuously, and LOCK keeps the one you like.
The double adds one to three gently re-performed voices that arrive at slightly different, slowly moving times: a human timing impression, not a chorus wobble. The harmony adds pitch-shifted voices above or below the lead, snapped to the key it hears, with the singer's vibrato and inflection kept. Both can run together, and KORO reports one fixed latency (54.10 ms at 44.1 kHz) whatever is on, so delay compensation never has to change.
$15. Updates appear on your Account page; the version you have keeps working forever.
macOS 11 or later · Windows, 64-bit · Standalone app, VST3 and AU on macOS; VST3 on Windows · One licence, your own computers, personal and commercial use · Paid through Lemon Squeezy in US dollars; refunds: subverselab.com/refunds
Sold through Lemon Squeezy. After you pay, sign in with the e-mail you paid with: the download appears on this page and on your Account page, with your licence key. Install and open it in your DAW. Your licence key is on your Account page; the current versions do not ask for it.