Aros Sextet: Train Song SONGLINES SGL SA 1546-2

Holland's Aros Sextet is the last of three bands on Upstream's Holland/Canada Series, following Ab Baars and Primal Orbit. They play tonight at 8 p.m. in Saint Mary's University Art Gallery, with a pre-concert chat at 7:30.

Curiously, considering Upstream's reputation for musical outrage, Aros do not commit musical mayhem.

They mingle jazz, minimalism, new music, tango and improvisation within astute classical frameworks. They never colour outside the lines. Occasionally the music is free, but never, except on the final track, Rocket Song, a free-for-all. And even that is tinted with minimalist devices.

Which means, in the absence of convenient pegs, with Aros you don't know what to think or where to hang your hat.

That's good, though. Thinking you know what to think often means you hear what you want to hear and don't hear what's there if you don't want to hear it.

Train Song is Aros's newest CD, just released or about to be released this month. It contains 11 tracks, all but one composed by co-leaders Rob Armus (a wholly admirable tenor sax player), and Marion von Tilzer, a pianist with conservatory chops who obviously loves classical but doesn't care to be classified.

They make use of pedal points - unmoving bass lines and unchanging or minimally changing harmonies. Amazing, it is how a steady bass monotone quickly establishes a law of musical gravity. You can layer up anything at all over the top, and the bassline grounds it so that it makes sense.

Meanwhile, there is Armus's richly resonant, beautifully centred sax sound, big and agile at the same time, even when he chooses, as in a track called 30, to spin out overtones and multiphonics as silky as rock candy wrapping itself around a paper cone at a carnival.

His embellishments of whatever tunes - usually modal ones, unfailingly melodic - are equally fluent and inventive, with just a few blue notes to give colour.

Von Tilzer, an extremely interesting writer who likes asymmetrical rhythms (Four 'n a half), ostinatos (Ostinato), and fuguish flights of fancy (Fugatisme), over which to lay angular, non-tonal melodies for everyone to texturalize and punctuate.

Her Song of the Heart features violinist Anne Wood, also classical in her approach to the instrument. Wood plays an expressive slow melody that is rendered more intense by the quarter-tone mist arising from the thumb piano attempting a selective, and not-quite-in-tune, unison with the piano.

On other tracks, Wood plays Philip Glass-like arpeggio figurations, as also does Armus in an amazingly fast passage in Rocket Song, a piece that the musicians take as an excuse to leap away from the spaceship into free-fall.

Trumpeter John Korsrud plays sparingly, though solidly, and percussionist Alan Purves proves his worth by being heard but not raising his voice to dominate the conversation. Bassist Sven Schuster, the only band member other than Armus and von Tilzer to be given a composition credit on the CD, plays a one-minute, 22-second tribute to bassist Charlie Haden.