Song key changer

A key changer shifts a whole song's pitch up or down by semitones while keeping the original tempo, so a track fits a singer's range without speeding up or slowing down. It works by pitch-shifting, separating pitch from duration, which is a different job from simply changing playback speed. Free, runs right in your browser, your file is never uploaded.

What is a song key changer?

A song key changer moves every pitch in a recording up or down by a set number of semitones, so the relationships between the notes stay identical and only the starting point moves. Dropping two semitones means every note in the track is two semitones lower, the melody unchanged, just sitting lower. Musicians call this transposing, and singers need it whenever the original arrangement was recorded in another vocalist's key. The technical difficulty is doing it to an already-mixed file: the software has to slice the recording into very short frames, shift the frequency content of each one and stitch them back together with no audible seams, all without making the song any longer or shorter.

How is changing key different from changing speed?

Speed change alters both pitch and duration together, the old tape-deck effect where playing something faster also raises its pitch. A key changer uses pitch-shifting to move only the pitch, keeping tempo and duration exactly as they were, so the song still matches its original arrangement.

How many semitones before the voice starts sounding off?

Within about 3-4 semitones, most ears will not notice any processing. Push further, especially past half an octave, and the voice's formants get dragged along with the pitch. It starts sounding thin, robotic, or cartoonish depending on direction. That is a physical limit of pitch-shifting algorithms in general, not something specific to any one tool.

Is shifting up or down safer?

Shifting down usually sounds more natural, because ears tolerate a deeper voice better than an artificially raised one. For high, belted passages, dropping a few semitones to fit your range tends to sound better than pushing up to hit the note.

Should you transpose the original track or a separated backing track?

The backing track, if you intend to sing over it. A file that still contains the original vocal carries that vocal along when the pitch moves, and a human voice is the first thing to betray the processing: a few semitones is enough to make it sound metallic or breathless. Instruments hold up far better, so the cleanest workflow is to separate the instrumental first, transpose that, then sing over it. If you are only listening, or working out what key a song is in, shifting the full mix by a few semitones is fine. And if you want the key left alone and only need the song slower to practise along, what you actually want is a speed changer, not a key changer.

Who needs a key changer?

• Karaoke singers who need a song raised or lowered to fit their range
• Anyone practicing to a track whose original key sits too high or low
• Cover bands transposing a song for a different vocalist
• Vocal coaches working with students across different vocal ranges
• Ringtone or backing-track producers matching key to a spoken voice

The steps to change a song's key right in your browser, nothing to install.

1. 1

   Upload the song or backing track

   Pick the file whose key you want to move. An already-separated karaoke backing track is the most common input.

2. 2

   Choose the number of semitones

   Each step is one semitone. A man singing a song written for a woman usually drops 3 to 5 semitones; a full octave is exactly 12.

3. 3

   Preview in the new key

   Play the passage containing the highest note in the song. That is what decides whether the new key fits your range, not the opening bars.

4. 4

   Download the shifted file

   Export a new file with the same length and tempo as the original.

• The further you shift from the original key, the more audible the processing becomes. Within 3 to 4 semitones it is usually hard to notice.
• Changing key does not change speed. If you want the song to run faster or slower, that is the speed changer's job.