Happy Apple's biggest problem — seven albums and 10-plus years into its career — is sustaining excellence. Although it's still a pretty abstract combo, the Minneapolis jazz group infuses its latest album, Happy Apple Back on Top, with genuine warmth and heart. Listen especially to the more tender tunes, which make up nearly half the new CD. The band's penchant for off-the-wall song titles also continues here. "Calgon for Hetfield" — with its gentle bass chords, straight-ahead drumming, and lilting melody — has got to be the prettiest song ever associated with the Metallica frontman.