Bobby Hatfield, 63; was half of pop icon Righteous Brothers

A Kalamazoo Public Safety spokesman said the cause of death is under investigation.

The "brothers" -- Mr. Hatfield doing gospel-tinged tenor and Bill Medley singing baritone -- forged a career together in the late 1950s. The ambition of the two clean-cut Southern Californians was to be a Las Vegas lounge act. They soon found a wider demand.

Under the watch of producer Phil "Wall of Sound" Spector in the mid-1960s, they created a handful of consummate pop-soul numbers that became a signature sound: slow rhythm-and-blues melodies with lush arrangements and melismatic vocal stylings.

Further attention focused on the duo being two white men exploring musical terrain dominated by black musicians. Mr. Hatfield's nickname was "the Blonde Bomber."

"Sometimes people with blue eyes transcended the limitations of what their color and culture can actually be," singer-songwriter Billy Joel said in March, when the Righteous Brothers were inducted into the Rock and Roll Hall of Fame. "Sometimes white people can actually be soulful. This was a life-changing idea. It changed my life."

Their best-known recordings had a popular revival a generation later when "You've Lost That Lovin' Feelin' " was used in the hit movie "Top Gun" (1986), when Tom Cruise crooned it to Kelly McGillis, and "Unchained Melody" became the love anthem in "Ghost" (1990), starring Patrick Swayze and Demi Moore.

With that newfound attention, they toured frequently. Mr. Hatfield told a reporter in Elmira, N.Y., this year that he had sung "You've Lost That Lovin' Feelin' " about 5,000 times.

"I get into those songs night after night, no matter how many times we do it," he joked. "And I know all the words by now."

Born in Beaver Dam, Wis., Robert Lee Hatfield grew up in Anaheim, Calif., where he helped his parents in their dry-cleaning business. He told a reporter last year that, in his youth, he drew upon black singers as his chief musical influence.

While attending what is now California State University at Long Beach, he became active in musical groups that played at proms and area dance parties. He met Medley in 1962 and formed a band with a few other musicians, dividing their first paycheck of $40 five ways.

Mr. Hatfield once said he and Medley, then performing as the Paramours, got the idea for their new name at a club near a Marine Corps base in Southern California. After they finished singing, he said, a black Marine in the audience called out, "That was righteous, brothers!"

Recording on the small Moonglow label, the duo had moderate success in 1963 with Medley's song "Little Latin Lupe Lu."

They came to Spector's attention in 1964 and recorded "You've Lost That Lovin' Feelin,' " which Spector wrote with Barry Mann and Cynthia Weil. They followed that with "Just Once in My Life," "Unchained Melody," and "Ebb Tide."

Moving on to Verve records, the duo had hits with "(You're My) Soul and (My) Inspiration" and "He." They broke up in 1968 when Medley, also a songwriter, wanted to pursue a solo career. Changing musical tastes also figured in their breakup.

They reunited briefly in 1974 to record the album "Give It to the People," yielding the hit "Rock and Roll Heaven." Starting in the 1980s, they reteamed and were working together at the time of Mr. Hatfield's death.

Their manager, David Cohen, told the Associated Press last night that Medley was devastated by the death. "He's not even coherent," Cohen said.

Mr. Hatfield had owned dance clubs, including one in Orange County called the Hop, which featured classic rock.

He leaves his wife, Linda Hatfield, and two children. After his wife was diagnosed with lupus decades ago, Mr. Hatfield helped raise money for the Lupus Foundation.