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"For while the showbusiness world eagerly awaits their return, aides closer to them have been less enthusiastic about their vocal abilities.
They are set to go into the studio to pre-record the songs for their tour - in order to mask the failings of their own live voices.
When the girls sing out of tune on stage, the mistakes in their voices are instantaneously corrected - in less than a tenth of a second - by computer to perfect the pitch and tone. And it is this remastered "virtual voice" which belts out across the arena. The girls' vocals are altered so quickly that it will appear the resulting perfect voices are live and their own.
The system is not miming as such, because they are not just mouthing music to a backing track."