There’s a telling admission about a minute and a half into Code Girl, the riveting new double album by Mary Halvorson. It arrives after she sets a mood on guitar, using pedal effects to loop her lines into a web — a tactic you’ll recognize if you know her heralded work as an improviser.
“It is not predictable, my mind,” goes the line in question, from a song called “My Mind in Time.” And the message in that refrain, sung with penetrating calm by Amirtha Kidambi, feels almost self-fulfilling. Halvorson’s music has always had the capacity to surprise, but Code Girl amounts to the most startling move in her solo career. It’s clearly the work of an unpredictable mind, and a personality drawn at once to unruly possibility and fastidious detail.
The album, just out on Firehouse 12 Records, features Halvorson and Kidambi alongside Ambrose Akinmusire on trumpet, Michael Formanek on bass and Tomas Fujiwara on drums. These are all musicians rooted in the jazz tradition, though hardly constrained by it. Mobilizing here around a batch of songs bearing Halvorson’s original lyrics, something for which she isn’t widely known, they create a music staunchly unplaceable in style — art-rock? avant-prog? — and mysterious in several other respects.