Clockwise is the third offering from Canadian-born bassist Michael Bates' ensemble Outside Sources. Charting impressive compositional growth since his previous album, A Fine Balance (Between the Lines, 2004), this session finds the Brooklyn-based composer leading his quartet through a dynamically varied program. Fueled by youthful verve, he deftly combines adventurous post-bop structures with the advanced compositional strategies of classical chamber music.

Bates' current touring quartet features longstanding partner Canadian saxophonist Quinsin Nachoff and ubiquitous Downtown musicians Russ Johnson (trumpet) and Jeff Davis (drums). With studied virtuosity, sensitive listening skills and intuitive interplay, they seamlessly blur the line between the written and improvised as they navigate Bates' thorny contrapuntal themes, staggered metric tempos and endlessly shifting rhythms.

The premier of a distinctive new voice, Bates has shed the influence of trumpeter Dave Douglas, whose shadow weighed heavily over his previous work. Driven by the same communal DIY aesthetic that informed his punk rock roots, Bates' writing employs the angular melodic ingenuity of his peers with an abiding interest in the emotional drama and harmonic complexity of the Russian school of classical composition.

"Great Exhibition" and "Fellini" demonstrate Bates' flair for opulent harmonies, cinematic atmospheres and elaborate counterpoint. The former blends neo-classical overtones with mercurial rhythmic accents while the later paints a carnivalesque portrait of the revered Italian director that episodically transforms from light-hearted to ominous.

Bolstering punchy hard bop with unfettered vigor, "Damasa" and "Machinery" veer from Ornettish elasticity to Milesian precision. The tenacious front line of Nachoff and Johnson provide cathartic intensity as they careen through Bates' labyrinthine compositions fueled by the leader's magnanimous contributions and Jeff Davis' roiling accents.

Bates' love of modernist Eastern European composers like Shostakovich, Prokofiev and Bartok reveals itself on "Machinery" and "Fellini," which incorporate fragments of Russian tinged folk melodies, while "Great Exhibition" invokes the ebullience of Stravinsky and the mini-trumpet concerto "Marching" employs a rousing, symphonic theme. Appropriately titled, "The Russian School" moves from petulant indignation to heartbreaking solemnity and back again; Nachoff's volatile tenor protests vehemently while Johnson's dulcet trumpet offers rays of hope.

Demonstrating compositional maturity and harmonic confidence, Bates also offers a selection of tunes that eschew high-minded complexity in favor of emotionally direct simplicity. "Rideau Medals" and "Lighthousekeeping" offer fleeting euphony that drifts from serene melancholy to bittersweet optimism. Similarly unadorned but far more assertive, the bluesy noir groove of "Bloodletting" inspires a gruff tenor testimonial from Nachoff accompanied by Johnson's expressively vocalized interjections.

Clockwise is a breakthrough album, revealing a wellspring of possibilities from an up and coming composer. A stalwart instrumentalist with sublime writing skills, Michael Bates is an artist to watch.