KALAMAZOO, Mich. -- The music world is mourning the loss of Bobby Hatfield, one-half of the legendary vocal group the Righteous Brothers.

His manager says Hatfield (pictured, left with Bill Medley) was found dead in a hotel room in Kalamazoo, Mich., Wednesday night -- just a half-hour before the duowas to perform on the Western Michigan University campus. He was63.

An autopsy is to be performed on Hatfield to determine his cause of death.

A hotel official told the Kalamazoo Gazette that Hatfield's body was taken to Lansing for anautopsy.

The duo's 42-year career featured pop standbys like "UnchainedMelody" and "You've Lost That Lovin' Feeling." They were inKalamazoo to kick off a four-day series of performances in Michiganand Ohio.

The Righteous Brothers were inducted into the Rock and Roll Hall of Fame earlier this year. The group's early hits were produced by embattled record producer Phil Spector, who created the legendary "Wall of Sound" recording technique that can be heard on such hits as "You've Lost That Lovin' Feeling" and "(You're My) Soul and Inspiration."

Their manager said it's a "real shock." He said Hatfield's partner Bill Medley is "broken up. He's not even coherent."

Formed in 1962, the Righteous Brothers are widely acclaimed as the greatest of the "blue-eyed soul" groups to emerge in the '60s. Some of their other hits include Ebb Tide" and the 1974 reunion single "Rock and Roll Heaven."