Wally Shoup and Paul Kikuchi's "Aurora Distillations"

Paul Kikuchi's a Seattle-based percussionist who releases fascinating recordings of improv wonderment under his own Prefecture Records imprint, when not kicking the traps in the Empty Cage Quartet. He's partial to site-specific performances, and indeed, his latest release -- Aurora Distillations, a duo with veteran free improv altoist Wally Shoup -- was recorded in an abandoned railroad tunnel. But this outing is a lot more virtuosic and jazz-like than recent Kikuchi outings with his ensembles Open Graves and Portable Sanctuary.

By now, free improv has a history stretching back a half-century (at least), with its own pitfalls and conventions -- which is not to imply that there's nothing new to be said in this arena. It's a truism, but it's also true that this music is often more fun to play than it is to listen to, but with players who possess the kind of instinctive ear for musical structure and contrast that Kikuchi and Shoup to, it's never the case here. They understand the importance of silence and space as elements in a sonic design, and the way such negative space places what is played in sharper relief.

In a way, what they're up to here is the same thing as Coltrane was in his late-period duets with Rashied Ali: exploring the root sounds of horns and drums, and their confluence. Shoup initiates "Apparitions" with a few plaintive bleats, to which Kikuchi responds with ghostly rattles. The saxophonist continues to unravel a stream of multiphonics and melodic fragments. The ambience of the tunnel provides the third "voice" in the dialogue. As Shoup ups the intensity, Kikuchi incorporates his trapset into the mix.

On "Deluge," Kikuchi unleashes a series of thunderous, timpani-like rolls on his toms, creating an auditory effect similar to what Boris achieved with Flood. Then Shoup joins in, alternately plumbing the lower depths of his horn's range, uttering woody squawks and squeals, and interjecting plaintive, Ornette-ish interludes of bluesy lamentation. Shoup's solo coda reminds us that an unaccompanied saxophone can be the loneliest sound in the world.

"Aperture" kicks off with tinkling percussion sounds that settle into a groove reminiscent of gamelan or Harry Partch. "Switchbacks" begins with another searching Shoup sax solo before Kikuchi joins in and the two musicians improvise in parallel, tentatively at first, as if regarding each other from a distance, gradually becoming more assertive as they intertwine their thought streams. Overall, Aurora Distillations is a heartening example of the perpetually renewing ability of exploratory musicians to uncover new dimensions of sonic delight. Cop digitally or on sweet, sweet vinyl here.