Handout photo issued by ITV of Electrolytes during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Julia Collins during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Mark McGregor during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Lynn Frances O'Neil during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Stephen during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Hollie during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Eric during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of George Bieknell during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Diva Features during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Stephen during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of G&S during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Damien during filming for an upcoming episode of the new series of The X Factor, in Manchester

Cheryl Cole during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Electrolytes during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Dice during filming for an upcoming episode of the new series of The X Factor

Handout photo issued by ITV of Christopher during filming for an upcoming episode of the new series of The X Factor

The X Factor show is embroiled in another production row after fans accused editors of using technology to make some contestants' voices sound better.

As the seventh series of the ITV1 ratings smash kicked off with more than 11 million viewers, people took to internet forums to rail against the use of "autotuning" during the programme.

Most of the allegations surrounded teenage contestant Gamu Nhengu, who sang a version of the Katrina and the Waves' hit Walking On Sunshine.

After hearing her effort, judge Simon Cowell told the 18-year-old from Clackmannanshire, Scotland, she was "really talented" before she was unanimously voted through to the next round.

But some viewers went online to accuse the producers of using autotune - used in studios to improve performances by correcting pitch and disguising off-key mistakes.

On the show's website, robhayes wrote: "Absolutely disgusting use of..autotune...does X-Factor really think we are idiots ? I see the idea of making the show more entertaining , but this is taking the mick .. really .."

Smstrat91 added: "Cannot believe they autotuned her, listen to the words 'door' and 'telephone' and its very clear. She's so good as well, but obviously the producers of xfactor didnt think she was good enough."

Similar accusations were made about another contestant, G and S singer Caroline, who also made it through to round two.

A spokesman for The X Factor said post-production work was necessary due to the number of microphones used during filming.

Saturday's first episode, which also saw Glasgow house husband Stephen Hunter go through after a soulful version of Disco Inferno, was watched by 11.1 million people, a big increase on last year's figure of 9.9 million.

PA