It was 2002 when the Black Keys released their debut album “The Big Come Up.”

Since then, they have released six studio records, three of them self-produced, and built up a large underground fan base. The band became more widely known in 2010 with their three Grammy-winning album “Brothers” and the hit single “Tighten Up.” Their follow-up was 2011’s “El Camino,” which won them another three Grammys, including two for the song “Lonely Boy.” Their latest effort, the highly anticipated “Turn Blue,” explores a much deeper and more mysterious sound.

Unlike the rough blues-rock of its predecessors, “Turn Blue” has a more retro and psychedelic feel. The album opens with the mystical xylophones of “Weight of Love” and a four-minute intro that would not feel out of place on Pink Floyd’s “Dark Side of the Moon.” The title track, “Turn Blue,” emulates producer Danger Mouse’s side project “Broken Bells” with falsetto backup vocals and mellowed-out electric strumming. The first single “Fever” is a catchy upbeat tune pairing a robotic electronic organ with the duo’s signature blues sound. The funky “10 Lovers” and ‘70s country sound of “Gotta Get Away” seem out of place and disjointed from the rest of the album.

“Turn Blue” represents a new direction and fresh sound for the Black Keys, more soulful and synth-driven, though it lacks a lot of the blues-rock riffs that originally defined their music.