Knechtel died Thursday at Yakima Valley Memorial Hospital of an apparent heart attack. His death was confirmed by a spokesman for Valley Hills Funeral Home.
Knechtel was born in Bell, Calif. He performed live and in studio recordings with a wide range of artists, including Neil Diamond, Randy Newman, Ray Charles, The Beach Boys, The Doors, Elvis Presley, Hank Williams Jr. and Elvis Costello.
He earned a Grammy award for his arrangement of Simon and Garfunkel's "Bridge Over Troubled Water," played keyboard on the Dixie Chicks' Grammy award-winning album "Taking the Long Way," and performed on the Hammond organ for the group's tour of the same name.
Knechtel moved to Yakima in 2003.