Artful meshing of sound and form is an important factor in making improvisation work. Without a core that draws the players, it doesn't work. If they let invention go off at different angles, the result can at worst be irksome and at best unsatisfying. Aercine offers a mixed bag.

When the pieces fall into place, Aercine is a potent force. The musicality on “Twofold Twice” flies off disparate tendencies voiced by the piano rumblings of Michael Jefry Stevens, who tempers them with lighter lines, the bowed bass of Steve Rust and the sharp trumpet shards of Herb Robertson. But they divine the path intuitively and spin an enticing web. Feldman captivates “Kaaterskill Falls,” a lone voice singing a mellifluous song that draws Rust and then drummer Harvey Sorgen into churning torrents of rhythm. Before it is over, Robertson and Stevens unleash hyper-energetic incursions and complete the spell.

Diverse elements mark their excursion to “The Shokoe Slip.” A fusillade of growls and a welter of scurries inject Robertson’s opening salvo. Stevens an ocean of calm soon ripples undercurrents of urgency, Feldman dances in on a folk air and a touch of klezmer. Where do they go from here? Right into an exploding cornucopia of sound, building tension and keeping it ticking until the last note slams in. For the most part they find common ground as they seek their muse on plateaus of their own invention. There are, however, a couple of occasions when they wander onto a woozy plain. For instance, “Renata” is left to dry across a bleak landscape, and “Aercine” comes across as indolent with neither a meeting of the mind nor of the spirit.

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