Austin-based singer-songwriter Chris Simpson, who was raised in Littleton, first came to the fore as a member of Mineral, a band whose two full-lengths, 1995's The Power of Falling and 1998's End Serenading, would undoubtedly hit the sweet spot of many a post-millennial modern rocker. Simpson, though, was too creatively restless to stick with this formula, moving on to form the Gloria Record, which accommodated a wider variety of styles — some simpler than those he mined in Mineral, others considerably more ornate. Now, as the main man of Zookeeper, he's heading for rootsier territory. "Snow in Berlin," the opening cut from the forthcoming CD Becoming All Things, is a rollickingly scruffy romp that pits acoustic guitar against trumpet and trombone, while "Boy & Street Choir" is a hushed ballad that couldn't be more emotionally naked if Simpson had recorded it in the buff. Given his track record, Simpson, who shares this bill with Umbrellas and Lydia, is likely to switch things up before long. But his latest band is definitely a 'keeper.