Tom Heasley plays the tuba. It's not classical tuba, it's not anything remotely resembling "traditional" tuba; Heasley plays - and warps, whorls, and wrinkles - his chosen instrument so far from any understood orthodoxy that attributing anything like a prescribed "method" to his style diminishes how original his approach is. Heasley's modus operandi fluctuates within, through, and beyond what the tuba's inventors might have dreamed up for their horn - married to digital processing, hard-disk looping, and sundry other electronic filtering, the vocabulary Heasley utilizes is nearly impossible to pin down. Pity the poor music journalist, trying to come to grips with terminology, labeling, pigeonholing, for Heasley's muse takes that poor creature down a slippery slope indeed, bypassing such mundane considerations as "jazz", "modern composition", the "avant-garde", or what-have-you. It is what it is; critical justification be damned.

But observation and evaluation are a different matter, neither of which tarnishes the experience. Overall, with Passages, his collaboration with drummer Toss Panos, Heasley is on what might euphemistically be called "electroacoustic-improv" footing here. Dive right in to the opening 24-minute "Different Worlds" for starters, as Heasley's mourning wail opens up a landscape colored the blackest pitch, the tuba strident, recognizable, reasonably straightforward. It doesn't last long: right as Panos dapples the surroundings with feathery-light cymbal work, in comes Heasley sending his brass through the ringer, coating its decay in electronic mercury, stretching the fat tones outwards to infinity. Panos is in obvious control of his kit, though he works in a grey area of sorts, often patiently waiting for Heasley's gaps to emerge before filling them with brash crescendos of snapping toms and near-martial snares. At first, the "meshing" of both musician's sensibilities feels diametrically opposed - particularly since Panos plays it clean, minus any electronic adornment - but as the minutes tick by and Heasley allows the percussionist room to breathe, Panos' sharp touches, flurries, and accents imbues the track with a powerful edge.

Further on, witnessed particularly well on the closing "Cliffs of Moher," Heasley pushes through soundscapes of a more "ambient" ideal, first revealed on his sublime Hypnos release Where the Earth Meets the Sky, reminiscent of ECM stables like Jan Garbarek and John Surman, two horn-men equally in tune to mergers of the ancient and modern built upon deeply meditational edifices. Panos affects a light touch that eloquently compliments the purring, generative textures Heasley invents, constructing something resembling a linear backbeat that looms larger into view as its momentum grows. For a finale, the piece packs quite a charged wallop, all traditional blueprints scattered to the four winds.