Anne Mette Iversen's Ternion Quartet: Invincible Nimbus

Anne Mette Iversen's Ternion Quartet is a frisky, loosely controlled ensemble with a fierce drive that recalls Charles Mingus' small groups. Iversen and drummer Roland Schneider push the music relentlessly forward while the front line of saxophonist Silke Eberhard and trombonist Geoffroy de Masure carouse boisterously on the top.

Iversen's themes carry traces of classical structure, like the fugue used in "The Rose Window" and the brittle, percussive chopping that begins "Polychromatic Pictures," but the music always resolves into thrilling jazz. Her thick, hard-swinging bass playing is a crucial part of this. It particularly stokes a fire under Eberhard and De Masure as they chug into the tense, stop-start pulse of "Dig Your Heels In" and dance acrobatically on "Within a Diapason."

"The Invinclie Nimbus of Mystery" blends the four instrumental voices with solemn formality before Eberhard rolls into a casual solo mixture of Bach and the blues. De Masure's trombone shadows her before the two engage in a giddy dialogue. "Four Snakes" is a tightly wound waltz mixed with a hint of circus music where the horns bob and weave over a gliding rhythm. On "Ionian Steps" the band simmers to a Caribbean groove before blazing into action. Eberhard honks and squeaks over a heated pulse before dialing down into yearning blues while De Masure lays into a series of mellow descending moans. The three "Ghost World" pieces are short unison statements of the quartet flying together on a cruising waltz, a brooding Ellngtonian theme and a brief series of ascending chords.

Iversen's quartet strikes a balance between structure and freedom that results in powerful, focused statements. Eberhard's alto playing refers to the sharp, off-kilter tones of Eric Dolphy and Oliver Lake but enfolds that into her own strong sense of melodic logic. Meanwhile De Masure's combination of a broad, creamy sound and wide-ranging playfulness comes off like the result of Glenn Miller hanging out with Roswell Rudd. Behind them Iversen and Schneider form a sleek rhythm machine that holds everything together. This is excellent hard-charging music by musicians who should be a lot better known.