Song Key Changer: Transpose

Song key changer for practice: transpose a song up or down to the key you sing or play in while its tempo stays the same, or slow it down without changing the pitch. Key Shift names the key, tells guitarists where to put the capo, and loops the part you are working on.

▶ CHANGE THE KEY
• Shift a song up or down by up to 12 semitones, with fine tuning in cents (±50).
• See the key by name, for example "G major → F major", on a circle-of-fifths wheel and a piano strip. Tap a key on the wheel to move straight to it.
• The original key is estimated from a 30-second part of the song and labelled as a clear or a weak match. If it's wrong, set the right key yourself.
• Changing the key leaves the tempo as it is.
• Note names as C D E, Do Re Mi or with German H.

▶ CAPO HELPER FOR GUITAR
• Choose a capo fret (up to 9) and read which shapes to play: "Capo 3: play D major shapes to sound in F major."
• Open-chord capo options for the new key are listed, lowest fret first.

▶ SLOW DOWN OR SPEED UP
• Tempo from 0.5× to 1.5× in steps of 0.01, with the pitch unchanged.
• Estimated BPM (60–200) and the BPM you're playing at now. Tap along to set the tempo yourself.
• See how long the song lasts at the new tempo.

▶ LOOP THE HARD PART
• Set A and B to repeat any part of half a second or longer.
• Count-in of 2 or 4 beats before each pass.
• Speed-up trainer: the loop gets 2% faster every 1 to 5 passes, up to the tempo you choose.

▶ EXPORT AND SETLISTS
• Export the whole song with your key, tempo and vocal setting as an .m4a audio file, then share it or save it where you like.
• Every song keeps its own key, tempo, capo and loop.
• Setlists for rehearsals and gigs: put songs in order, see the total length at your tempos and go to the next song from the player.
• Reduce centre vocals on stereo recordings.
• Keeps playing with the screen off or while you use another app (you can switch this off). On newer Android versions this needs notification permission.

▶ GOOD TO KNOW
• Key and tempo are estimates from one part of the song. Songs can change key, so check by ear and correct the key when needed.
• Vocal reduction cancels sound panned to the centre: often the lead vocal, but also bass and drums. It is not vocal separation and works only on some stereo recordings.
• Large shifts can sound processed, especially voices.
• Add songs from your files: audio files, or a video to use its sound. The app keeps its own copy of each song. Songs from streaming services can't be added.
• An export holds the whole song; loops and the trainer are not included.
• A backup holds your song names, settings, loops and setlists, not the audio files.
• Songs and settings are saved in the app on this device. No sign-in.
• A banner ad appears on the Library screen, and full-screen ads at some moments, never while a song is playing or exporting.

Recent changes:
Fixed: tapping “Cancel” while “Export shifted audio (.m4a)” was running could stall the screen for several seconds on some phones. The export now stops in the background and the app stays responsive. Also fixed: a play button on headphones or Bluetooth pressed while no song was open could close Key Shift; it is now simply ignored.