By Mark Egan

NEW YORK— A baby-faced high school student likened to an old-fashioned crooner and a scruffy bartender who sings alternative rock music will compete in next week’s season finale of US television’s "American Idol."

Guitar-playing rocker David Cook, 25, and 17-year-old piano balladeer David Archuleta beat out the final female contestant, Syesha Mercado, 21, after voting was revealed on Wednesday’s broadcast of the most popular US television show.

"After 56 million votes, America has decided that the two people going head-to-head in our finale next week are David Archuleta and ... David Cook," the show’s host Ryan Seacrest said during the live broadcast, sending Mercado home.

On Tuesday, each contestant had to perform three songs – one picked by a judge, one chosen by the performer and one selected by the show’s producers.

Throughout the seventh season, the two Davids have been favorites among the show’s judges and pundits, while Mercado came close to elimination on several occasions.

More than once, judges suggested she was more likely to make it big singing on Broadway than as a pop star. Still, her performances impressed them increasingly in recent weeks until Tuesday, when they said she struggled.

Her rendition of Peggy Lee’s "Fever" on Tuesday was drubbed by no nonsense "Idol" judge Simon Cowell as "a lame cabaret performance."

But as she was voted off the hit show on Wednesday Mercado remained gracious, saying to her fans, "I just want to say thank you" before singing on "Idol" for the last time – performing the Alicia Keys hit "If I Ain’t Got You."

This year has seen the second straight season of declining ratings for the show, which airs on News Corp’s Fox network.

Last week 21.8 million people watched Tuesday’s episode, the lowest Tuesday audience in over five years, and 22.9 million people tuned in for Wednesday’s vote, the worst Wednesday audience in three years, data from Nielsen Media Research showed. Last year the show routinely topped 30 million viewers.

But by some measures it could claim to be more popular than politics. During last year’s season finale 74 million votes were cast – 12 million more than the 62 million votes cast for President George W. Bush when he was reelected in 2004.

Unlike in presidential elections, fans of American Idol are allowed to vote multiple times, and some do dozens of times.

"American Idol" pits singers against one another in a months-long competition that awards a recording contract to the winner. Past winners such as Kelly Clarkson and Carrie Underwood have gone on to music stardom.