Question 1

How does it find the key of a song?

Accepted Answer

It measures which of the twelve notes sound most across the first minutes of the song and compares that with the pattern each major and minor key is known for (the Krumhansl-Kessler key profiles). It is an estimate: a song that changes key or borrows chords can mislead it, and a key is most often confused with its relative major or minor - C major and A minor use the same notes - which is why the page offers the next most likely key too.

Question 2

How do I find the right key for my voice?

Accepted Answer

Play the song and move it down a semitone at a time until the high notes are comfortable, or up until the low notes are; the page shows the key you end up in. A song recorded by a singer with a much higher or lower voice than yours can need a move of five or more semitones.

Question 3

Can it change a song from major to minor?

Accepted Answer

No. Changing key moves every note by the same amount, so a major song stays major and a minor one stays minor. Turning major into minor means changing some notes and not others (the third, sixth and seventh of the scale), which a recording of the whole band mixed together does not allow.

Question 4

What is A = 432 Hz tuning?

Accepted Answer

Standard tuning puts the A above middle C at 440 Hz. Some musicians prefer 432 Hz, about 32 cents (a third of a semitone) lower. The A = 432 Hz button moves the whole recording down by that much, or by less if it measures a little flat already; an A = 440 Hz button appears when a recording measures off standard pitch, to bring it back.

Question 5

Will the singer still sound like themselves?

Accepted Answer

For a few semitones, yes, with Keep voices natural on: the notes move but the resonances that make the voice sound like that person stay put. Moves of more than about five semitones start to sound processed, as they do in any pitch shifter.

Key changer: transpose a song to another key