Jeff Platz / Kit Demos / Fabio Delvo / John McLellan: Differential Equations: Jeff Platz / Kit Demos / Fabio Delvo / John McLellan

Those drawn to free improvised music can attest to the appeal of the style: the constant flow of ideas and the crackling energy of instantaneous musical interactions. When an improvising band is "on," you know it. What you're hearing is the sound of others listening intently and responding in the moment. Heavily dependent on group chemistry, the success or failure of a free improvising group hinges on the ability of its members to participate in a sort of give-and-take that balances individuality with one's willingness to subsume his identity to facilitate group interaction. These processes are quite palpable on Differential Equations. The nominal leader of this otherwise cooperative session, guitarist Jeff Platz, is blessed with the ability to identify players with the ability to make things happen within an ensemble while maintaining a distinct voice. Accompanying Platz in this Boston-based ensemble is drummer John McLellan, known primarily for his work with the legendary saxophonist, clarinetist, composer and out-of-the-box thinker Joe Maneri. Here, McLellan gets to cut loose, and his persistent, simmering rhythmic drive is a major enabling factor. Bassist Kit Demos is a fixture in the New England new music scene who's worked with Joe Morris and Jim Hobbs. His brawny sound and telepathic interaction with McLellan are two more reasons why this music engages so strongly. Saxophonist Fabio Delvo is a new name to me, though he's worked extensively with legendary Italian jazzers such as Claudio Fasoli and Giovanni Tommaso. He's not an ecstatic sort, and clearly prefers a cooler jazz-based approach. That said, his playing on Differential Equations is warm, effusive and-at times-quite lyrical, a bit like an alto-playing version of Tony Malaby or Joe Lovano.

Though the music is credited to the group, there's a liberal smattering of written-out themes and compositional devices. In fact, several of the pieces here-namely "Caribbean," "Bell Clear," and "Sonar"-are reminiscent of the loosely arranged free-bop approach favored by drummer Paul Motian, documented on a string of fine albums recorded for the ECM label in the 1970s and 80s (e.g. Tribute, 1974, ECM Records, and Psalm, 1982, ECM Records). "Son Of Clooney" possesses the date's most complex and involved compositional matter, a convoluted be-bop theme that easily translates into a heated dialogue between Platz and Delvo. Elsewhere, the quartet explore free-er terrains. "What Phenomena!" is a drums / saxophone duet that moves through a variety of tempos and moods. McLellan also gets considerable solo space on "Urla Libere," which develops into a high energy conversation between all four members of the quartet. Demos and Platz apply subtle electronic effects to "Bill Burroughs" and "Onde E Lamenti Dal Cosmo." Here, the electronics are clearly not a gimmick, but are a central part of the quartet's sound. A high school science and math teacher by day, Demos has been building his own synthesizers for decades. Here, these devices serve to enhance the timbral and tonal palette of a band that's already stretching their respective instruments to their limits.

Naming your album Differential Equations certainly suggests that there's some brainy activity going on in the music therein. Yet, there's nothing cold or calculating happening here. If anything, the title gives short shrift to the obvious warmth and freewheeling spirit of the quartet's consistently engaging and largely improvised music.