Cate Le Bon at DC9. (Kyle Gustafson/For The Washington Post)

Most of Cate Le Bon’s songs include gentle, if slightly tart, passages that draw on venerable Celtic balladry. But the Welsh singer-guitarist, who performed Wednesday night at a crowded DC9, also likes to make an unholy racket. So it’s fitting that she opened her one-hour show with a thumping yet intermittently delicate number titled “No God.”

That song, like nearly all of the ones played by Le Bon and her black-clad backing trio, came from her recent album, “Mug Museum.” Although recorded in Los Angeles, it doesn’t mark the performer’s move toward a sunnier or more commercial style. (Le Bon made her biggest concession to mainstream pop two albums ago, when she stopped recording material in Welsh.) Her melodies are pretty, with pleasantly unexpected modulations, but also frequently dirge-like. And when Le Bon goes uptempo, cacophony often travels with her, even if it’s just to compress the epic din of the Velvet Underground’s “Sister Ray” into anarchic 20-second outros.

Dressed in a long silver sheath and accessorized with black boots, black eye makeup and a black guitar, Le Bon might have seemed a bit intimidating. Her icy alto, and her reputation for writing songs about death, buttressed that impression. But fans who saw her looser, less-attended show two years ago at the same venue already knew the performer is not cold or humorless. Between-song patter was brief but friendly, and basic garage-rock riffs proved the band wasn’t taking itself all that seriously. When time came to pause before the encore, Le Bon and the others simply crouched for a moment, partially out of sight, rather than make the pointless walk to the dressing room and back.

When Le Bon switched to one-handed organ, her playing was as direct as Daniel Ward’s drumming. Other aspects of the band’s sound were more intricate, however. All three backing players sang, using falsetto to harmonize closely with the lead singer, and Le Bon and H. Hawkline deftly interwove their trebly guitar figures. (For the record, the two musicians’ given names are Cate Timothy and Huw Evans.) Le Bon may be part folkie, but she’s no simple strummer. She traded lead lines with Hawkline, and shifted confidently from folk-rock to a bluesier style for “Duke.”

Two tunes from 2012’s “Cyrk,” the energetic “Falcon Eyes” and the more elegiac “Fold the Cloth,” were well-received. But the song that best showed the group’s range was “Wild,” which climaxed the main set. It was alternately earthy and soaring, with its title extended into airy trills of “Wi-eye-ld” and a final foray into German motorik trance-rock that drove Le Bon’s semi-trad style into, if not the future, at least the 1970s.