Rachael Yamagata has hardly been idle since her acclaimed 2004 full-length debut, Happenstance and its Adult Top 40 hit"Worn Me Down."So for her Warner Bros. premiere, the singer-songwriter-pianist with the sultry voice unveils a double-disc set. Produced largely by Mike Mogis (Bright Eyes, Rilo Kiley, the Faint), and also John Alagia (John Mayer, Dave Matthews Band, Happenstance), Elephants is darker and more vulnerable while the more guitar-driven Sinking Into Heart is grittier and definitely more defiantly cynical. Together, they reveal the two sides of one of today's most entrancing artists.