Turned loose in the studio, three enormously talented guitarists, accompanied by solid percussion, drums and programming, might well produce a super session. Charlie Hunter’s patented eight-string sound knows no parallel; search out his start-to-finish instrumental reimagination of Bob Marley’s Natty Dread album on Blue Note. Ernest Ranglin practically invented ska guitar, and his recent work with Jamaican pianist Monty Alexander is sublime. “Chinna” Smith has backed all the greats (the Abyssinians, Black Uhuru, Burning Spear, Jimmy Cliff, Bob Marley and Tommy McCook, among others). But ventures like this owe their success less to overpowering talent than to a disciplined producer’s vision, and Earth Tones goes half the distance. The best tracks are wonderfully inspired yet coolly understated (the sizzling Smith-Hunter creation “Long Bay,” Edie Brickell’s “What I Am,” Hunter’s “Mestre Tata,” Smith’s “Fade Away”), but other material is limp and listless. Ranglin’s tasteful playing underpinned the Melodians’ blockbusting original “Rivers Of Babylon,” sadly redone here as an elevator afterthought; and “Island In The Sun” (the Caribbean chestnut erroneously attributed in the notes to “I. Burgess”—it’s actually by the inimitable Irving Burgie) receives similarly slack treatment.