Cher's next album, "Backstage" (1968), in which she explores diverse musical genres including Brazilian jazz and anti-war protest settings, was not a commercial success. In 1969, she was dropped from Imperial Records. Sonny and Cher had been dropped from Atco; however, the label wanted to sign Cher for a solo album. "3614 Jackson Highway" (1969) was recorded without the guidance of Sonny in Alabama with prominent session musicians the Muscle Shoals Rhythm Section (who appear on the album's cover along with Cher) and incorporates experiments in rhythm and blues and soul music. AllMusic's Mark Deming proclaimed it "arguably the finest album of her career", and still "a revelation" decades later. Displeased with the "3614 Jackson Highway" album, Sonny prevented Cher from releasing more recordings for Atco.