A scant year and a half ago, Gann Matthews resembled nothing so much as an unplugged disciple of Thom Yorke and Isaac Brock. What a difference a few months make. The young troubadour has swiftly graduated from shaky-throated emulation to sure-footed maturity, trading in indie pallor for a rich, ruddy rootsiness that teems with guts and depth. His debut disc, The Thin Line, is a dexterous exercise in classic folk/pop syntax that's as candid as is it crafted. Just 23, Gann Matthews is already at the head of Denver's singer-songwriter herd. Give him a couple more years; he'll be unstoppable.