Guitarist Mary Halvorson is most often heard in controlled settings. From her songwriting partnerships with Jessica Pavone and Kevin Shea to her own jazz trio to her participation in the structured frameworks of Anthony Braxton's ensembles, her level of output is perhaps all the more impressive given that so little of it stems from impromptu meetings.

Which perhaps is the point of the trio Crackleknob: what for others is a career for Halvorson might be taken as a conceptual approach. Her two partners in the trio � trumpeter Nate Wooley and bassist Reuben Radding � are more often to be found in free improv situations. And while the group works as a collective � or, at least, all compositions are jointly credited � and indeed is hardly impromptu as they've been playing together in different groups for a half dozen years, it is Halvorson that gives it its name, or rather her guitar and its noisy loose wire she is so fond of. (Listen closely: she plays the static of the knob on many of her recordings.)

Crackleknob the CD is comprised of mostly short scenes (only one of the 10 tracks is more than six minutes) that are consistently dynamic without being rushed. All three use repetition, fore and background, and silence for the greater good, making for a quietly exciting session. There's no drive to jam here, nor is there an effort to push the doctrine of unlikely sounds. Instead, Halvorson, Radding and Wooley comfortably, confidently, make something quite their own. Loping phrases travel from one instrument to the next. Musical statements intermingle with seemingly unrelated ones, and then with nonmusical ones. If they rushed it, it wouldn't work, or at least would work very differently. But Crackleknob the trio seems smartly out to prove nothing.