The echoes of Constitution Hall obscured the finer points of the sets by Warren Zevon and X last night, but the aggressive efforts of these two L.A. acts to stretch their sound in new directions came through unmistakably.

Zevon, the headliner, led a hard-rock quintet that put some muscle into his singer-songwriter material. His more macho songs about mercenary soldiers, boxers and hard drinkers benefit from the new wallop, but the sly humor and irony of his best writing were often lost amid the cacophony.

The legendary Little Feat rhythm section of Richie Hayward and Kenny Gradney was largely wasted on the stiff, unsyncopated martial beat. Zevon's limitations as a singer were as obvious as ever, especially when he tried to outshout the jackhammer beat of his newer songs.

By contrast, X has discovered a new freedom and power in its newly expanded sound. In the middle of a fast, slam-dance version of "Devil Doll," X bassist John Doe dropped in a snatch of Hank Williams' "Your Cheating Heart"; he not only made the transition work, but he sang the plaintive honky-tonk as well as he sang the pell-mell punk.

Using punk and country as its benchmarks, X staked out a large swath of American music and made it its own.

Tony Gilkyson capably filled Billy Zoom's guitar slot, and Exene Cervenka's unorthodox vocals were as eerie as ever.

Baltimore's Doe carried the show, though, with some of the best vocals and new songs of his career. When he sang "See How We Are," the title track from the band's best album yet, his knowingly understated vocals evoked a vision of America that was as unnerving as it was convincing.