Julia Holter (center) performs at Sixth & I Historic Synagogue. (Josh Sisk/FOR THE WASHINGTON POST)

The downstairs room at the Sixth & I Historic Synagogue doesn’t share the same ornate, mystical vibe as the main hall situated above it, but it is an inviting space. Couches were lined up in front of the stage for Julia Holter’s show Thursday night, with 10 to 12 rows of chairs behind. With 120 or so people gathered, the event felt like a gallery or university happening, appropriate for the L.A.-based artist’s often high-concept music. Her tumbling, bewitching performance — highlighted by five new songs — was a tidy summation of her career: a mass of solemn and stately experimental music, with a palpably throbbing heart under the surface.

Kicking off a month-long international tour that will stretch through the release of her album “Loud City Song,” Holter was supported by a lithe ensemble constructed from cello, violin, saxophone and drums. Behind Holter’s keyboards and chutes-and-ladders vocals, the band extended its tendrils most effectively around the new material. Several older songs were refreshed with updated arrangements, allowing the group to slink along like avant-chamber rockers.

Holter’s new songs combined the touchstones of her previous work — ambient moodiness, precise note placement — with a relatively romantic lilt. “World” and “In the Green Wild” were received best by the rapt audience. But “Horns Surrounding Me” and “Maxim’s 2” dug the deepest. The former, which Holter said was about “running away from something,” trundled along in a gripping, robotic lurch, strings and drums in lockjaw step. The latter, keyed by a roiling solo from saxophonist Danny Meyer and sinewy lines from violinist Andrew Tholl, was the night’s peak, a transporting piece that seemed to be pulled from a long-lost, ahead-of-its-time, 1960s musical.

Performances of Holter staples “Four Gardens,” “Marienbad” and “Try to Make Yourself a Work of Art” framed the hour-long set nicely, but it was the sparkling new work — and the way the band fit so snugly around her ambitious songs — that made the performance fascinating.

The opening set from Holter’s fellow Californian, Jessica Pratt, had no tumbling, widescreen ambitions. An unbroken pulse of tremulous songs, Pratt pushed a spike into the mainline of folk music and conjured spirits from the cellar of history, from Joni Mitchell to Maybelle Carter to Karen Dalton. Her hunched, intense presence was an ideal pallete cleanser for Holter’s magnificent follow-up.

Foster is a freelance writer.