While known as a progressive bluegrass band that can set stringed instruments aflame like the best of 'em, Austin's The Greencards aren't just technical marvels; they're also accomplished songwriters, as evidenced by their sixth album, Sweetheart of the Sun. It's a song cycle about movement and water; founding members Kym Warner and Carol Young are Australian transplants. The album finds the band dialing back their penchant for exploratory jamming in favor of a more placid vibe. "Black Black Water" is approaching minimalist for a bluegrass band (brushed drums and plucked mandolins provide the backdrop for Young's languid vocal), but the track's gentle pace is graceful and affecting. Most of the album ("Ocean Floor," "Traveler's Song") is similarly subdued, but the dexterous plucking on tracks like "Wide Eyed Immigrant" and "Paddle the Torrens" prove the band still have chops to spare.