Though both Syleena Johnson and Musiq Soulchild are accomplished soul vocalists with broad and eclectic discographies, they may be best known for their collaborations with other artists. Johnson has lent her considerable vocal firepower to tracks by an array of stars, most notably Kanye West, who enlisted Johnson to sing the hook on his debut single, “Through the Wire.” Musiq’s own high-profile collaborations include guest turns on albums by the likes of The Roots, Santana, and Talib Kweli. It’s something of a surprise, then, that 9ine—Johnson and Musiq’s reggae-inflected full-length—is a subdued, off-the-cuff effort rather than a flashy affair with a star-studded roster of guest artists. The album thrives off its own unassuming low-key ambiance. Musiq and Soulchild maintain this with the aid of producer Kemar McGregor, whose gently loping rhythms invoke the nostalgic lovers' rock of latter-day dancehall stars like Sanchez and the more relaxed productions of ‘80s-era Jamaican studio wizards like Bobby Digital and Steelie & Clevie. Those willing to broaden their horizons should find much to enjoy on this gentle but unfailingly winning album.