This article is part of Yahoo's 'On This Day' series
When Cher's Believe went straight to the top of the British charts in 1998, it marked the start of a seven-week reign at No 1 – and was the first global hit that used Auto-Tune.
But for years afterwards, the producers did not admit the pitch-altering software had been used on the smash hit which topped the charts in 21 countries.
Auto-Tune had only been launched in 1997, and Cher’s producers initially claimed the strange "wobble" on her vocals had been created using a vocoder (a voice effect previously used by Kraftwerk).
Believe debuted on this day 22 years ago, and remains the biggest-selling single by a female in the UK: it was the lead single from her 22nd album, and marked the end of a career lull.
She said then: "There was a time not too long ago when I thought my career had hit rock bottom."
The producers turned to Auto-Tune after Cher heard a single created with vocoder and said, "Let’s try that."
Mark Taylor created a version of Believe using Auto-Tune, but was initially too nervous to play it to Cher, he told the New York Times.
He said: "A couple of beers later, we decided to play it for her, and she just freaked out."
Cher said: "We high-fived. It was like some stupid Rocky film."
The technology behind Believe is now almost ubiquitous in the music industry, both to create the vocal effects on songs such as Rihanna’s Disturbia and to correct wrong notes.
The software was created by oil engineer Andy Hildebrand, who had previously worked in seismic data exploration using echoes to map areas underground while looking for oil.
But Hildebrand, who had a musical background, realised the "autocorrelation" technology he used could also be used to detect pitch and correct flat or sharp notes.
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Hildebrand said he hoped the software would mean that singers would be able to record songs in one take, rather than having multiple recordings spliced together.
His original patent said: "When voices or instruments are out of tune, the emotional qualities of the performance are lost."
The producers of Cher’s hit didn’t admit to using it, Hildebrand said, because, "They didn’t want to be known to manipulate the pitch of sound."
Even in interviews a year later, they maintained that the unusual effect had been created by a Digitech Talker vocoder pedal.
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The famous robotic wobble is created by turning the speed with which Auto-Tune changes pitch to "zero" and creating rapidly alternating pitches that some producers describe as "the gerbil".
Hildebrand said: "When a song is slower, like a ballad, the notes are long, and the pitch needs to shift slowly. I built in a dial where you could adjust the speed from 1 (fastest) to 10 (slowest). Just for kicks, I put a 'zero’ setting, which changed the pitch the exact moment it received the signal."
It’s that robotic ‘wobble’ which has become a ubiquitous effect in music, used on everything from One More Time by Daft Punk to Kanye West's Heartless to T-Pain's Buy U A Drank.
According to some estimates, 99% of current pop records use Auto-Tune.