Musicians who lean toward a cerebral approach face two challenges: avoiding contrivance, and ensuring there’s enough emotional content to resonate with listeners on an instinctive level. Altoist Rudresh Mahanthappa has been performing an uncanny balancing act in that regard since he relocated to New York in the late ‘90s. He’s been making as much of a name for his own work as he has as a member of pianist Vijay Iyer’s various projects. The two share a cultural heritage and approach that manages to find the nexus point between East and West without sounding quite like either.

As its basis, Codebook has an intellectual conceit: applying symbols and mathematics to shape musical communication. In lesser hands this route might reek of contrivance, but Mahanthappa makes it an honest and emotionally powerful work.

Codes are all about patterns, and Mahanthappa’s music revolves around structured forms, at least as underlying foundations. They might be construed as restrictive if it weren’t for the broad-mindedness of his superb quartet partners: Iyer, bassist François Moutin and drummer Dan Weiss. Iyer’s the best-known of the bunch, but Moutin has been building a reputation with both Mahanthappa and his own Moutin Reunion Quartet. He’s an engaging combination of visceral energy and rhythmic/harmonic complexity, qualities which dovetail perfectly with the increasingly ubiquitous Weiss, who seems to have no limit in terms of stylistic reach. Together they push the fiery and rhythmically staggered “The Decider,” create a darker underpinning for the more oblique and Eastern-inflected “Refresh,” and combine for a remarkably funky yet fluid backbeat to support the metrically challenged “Enhanced Performance.”

What takes Codebook out of the realm of clever convention and makes it a powerful statement is the freedom with which every player approaches the material. Mahanthappa is on fire throughout, creating cascading lines that sometimes feel at odds with rhythms that sometimes simmer, other times boil, underneath. His tone is surprisingly dry, reminiscent at times of Norwegian saxophonist Jan Garbarek. But while Garbarek has become a leaner player over time, Mahanthappa isn’t afraid to build complex lines that serve as catalysts for the rest of the group, directly or indirectly cuing directional shifts.

On “Frontburner,” which begins with Mahanthappa in duet with Weiss, there’s a sense of abandon that’s in direct contrast with the boppish theme and near-swing of “D (Dee Dee)," which ultimately dissolves into an open middle section featuring the imaginative and unencumbered Moutin.

Codebook proves that pattern-based music needn’t be rigid. For Mahanthappa, the approach is simply a way to provide context. Consequently, this exciting and distinctive disc continues a string of impressive albums that began with Yatra (RM, 2001).