Singer-songwriters John Hiatt and Shawn Colvin have a lot of fans in common, but during their solo acoustic sets Sunday night at the 9:30 club, they seemed like polar opposites. While Colvin's mellow hour demanded the audience's complete silence, headliner Hiatt kicked things up to a rowdier level with pointed references to Hurricane Katrina.

During his opening song, "Drive South," Hiatt described a road trip to help New Orleans and Mississippi. Amid choruses of "C'mon baby, drive south," he incorporated pleas for donating canned goods, gave out the Red Cross's Web address and delivered a fierce political commentary, "We'll get there faster than the government did!" A few songs later, Hiatt altered the lyrics to his song "The Tiki Bar Is Open," adding the mournful line, "But if New Orleans don't open up again sometime, I might just disappear."

But the concert was more than a series of shout-outs to the Big Easy to get the crowd to react. Tirelessly energetic, Hiatt blazed through aggressive songs such as "Memphis in the Meantime" and "Master of Disaster." Even when he slowed down for the more delicate "Back on the Corner," his plaintive voice and driving guitar work pushed the music forward.

While his two-hour set mostly avoided politics, the evening's most poignant moment tapped into a long history of activism in this country. With a thinly veiled reference to New Orleans, Hiatt and Colvin returned to the stage for a second encore, a moving duet of Woody Guthrie's "This Land Is Your Land."

-- Catherine P. Lewis