American Idol debut hits sour note

Los Angeles - The audience for American Idol dropped by some 18% to 21.6 million viewers when the TV singing contest returned for its 11th season, according to early ratings figures on Thursday.

The drop was even bigger - about 27% - among viewers aged 18 to 49, the audience group most coveted by advertisers, Nielsen figures showed.

But despite the fall-off, which Fox television executives said they had expected, the two-hour American Idol season premiere was still the most-watched show by a huge margin on US television on Wednesday.

26.2 million viewers tuned in to watch the 2011 season premiere when new judges Steven Tyler and Jennifer Lopez made their first appearance.

Fox television chairman Kevin Reilly said that the network was expecting the audience for American Idol to be down this season because of the show's age.

But media watchers say Idol - the most-watched show on US television for seven years - faces the stiffest competition ever in 2012 from rival singing contests The Voice on NBC, and the debut season of The X Factor on Fox, which ended just one month ago.