In the decade since Cher's hit Believe, with its distinctive robotic warble, singers have been relying on revolutionary software called Auto-Tune to correct and synthesise their wayward pitches. But now the manipulated sound is everywhere and a backlash is building.
On his new album, the reigning king of hip-hop, Jay-Z,launched an attack on the process in the song D.O.A. (Death of Auto-Tune). He says: "I know we facing a recession but the music y'all making gonna make it the Great Depression."
The song has sparked a battle with rival singer T-Pain, who believes so strongly in Auto-Tune that he has joined forces with its maker, a California software firm, to release a version as an iPhone application that quickly moved to the top of the sales chart. Though the pair have since cooled their language, T-Pain lashed out: "Jay-Z is 59 years old. I don't think he has the right to say what's good and what's not. I think if anything is dead, it should be him ...
"Manipulating the voice," he says, "is the future" and a welcome change from unadorned singing which, he says, people have been doing for centuries. "Now everyone wants to be a Transformer."
But do they? Some say using machines to manipulate pitch erases the distinctiveness, resonance and emotional power of the human voice. Perfect pitch is rare and natural flaws and imperfections are often what make a voice memorable and affecting.
It is also a question of fidelity. Critics say that if every voice is corrected and anyone can achieve perfect pitch, then singing itself could lose its value.
"I can't recognise real singing any more," the singer Moby said recently.
George Martin, the Beatles producer, says singers are rarely satisfied with their sound and adding effects such as reverb are just tricks of the trade. "John [Lennon] was never satisfied with the sound of his voice," he told the New Yorker.
