They may disagree on precise definitions, but the characters of Warren Leight’s “Side Man” agree there is a fundamental difference between an “addict” and a “junkie.” Whichever category he falls into, Gene (Fran Kranz ’04), the side man of the title, has it bad. But Gene is doomed because the source of his obsession, jazz, condemns him to obsolescence.

“Side Man,” playing at the Whitney Humanities Center this weekend, depicts two shadowy worlds: the world of the jazz musician and the world of the jazz musician’s family. Gene’s obsession leads to his personal degeneration and the collapse of his family, which echoes the decline of the art form’s popularity.

Even at the height of jazz, the “side men” — versatile, itinerant supporting players — suffered from drug addiction, alcoholism and exploitative music industry practices. Yet they enjoyed little of the fame of the kings of the art like Miles Davis or Charlie Parker.

As a group, they proved particularly vulnerable to the popular decline of jazz after the big-bands of the 1940’s to the 1950’s, when it became a far more specialized art form. By the 1960’s and 1970’s, as rock and roll exploded onto the scene, they were marginalized.

“That kid will do to horn players what talkies did to Buster Keaton,” Jonesy, a trombone player, predicts after seeing Elvis on “The Ed Sullivan Show.”

The character of Clifford, Gene’s estranged son, frames the play. He narrates much of the action, delivers opening and closing monologues, and weaves in and out of flash backs stretching back to before his birth. But instead of serving as a center of calm for the play, Clifford is as damaged as his parents. His character’s narration dances around the conventions of the psychology of addiction — “co-dependence,” “enabling,” “denial” and desires for “closure” abound — without ever falling into the trap of the cliche.

Though he acknowledges that “there are no clean breaks,” Clifford hopes to escape his tangled past by embarking for the West.

Just before his departure, Clifford visits the club where his father has been a regular for years to say farewell. There he takes in what will probably be his last opportunity to see his now-estranged father play his trumpet.

Clifford arrives to find his father playing “I Remember Clifford,” about his namesake, the jazz legend Clifford Brown. This performance serves as a stimulus for the flash backs to 1953 constituting the bulk of the scenes, when Clifford’s parents were young.

It is also a cue for the entrance of the best thing about this show: Kranz’s performance. Kranz perfectly portrays the preoccupation of single-minded devotion which doesn’t leave room for anything else. Even as his neglect drives his wife to alcoholism and insanity, and deprives his son of his childhood, he remains likable and vulnerable — an object of pity, not revulsion.

But Kranz’s performance cannot compensate for the actors’ inability to directly respond to the music itself, at a crucial moment.

In the would-be revelatory scene set in 1967, the four side men listen to a 1956 tape of the late Clifford Brown’s trumpet solo on “A Night in Tunisia.” The recording, of a jam session on the night the 25-year-old musician was killed in a car accident, was a jazz legend even before it was released in 1973.

None of these fine actors seems able to communicate his characters’ passion for music, the reason for all of their own and their families’ sacrifice. They wag their heads, tap their feet, smile and exclaim — but at moments it didn’t even seem they were reacting to anything in the music. This seeming disconnectedness was a small but crucial gap in the show.

Fortunately, the side men were much more effective in reacting to each other. Jonesy (Blake Edwards ’02), a gentle junkie; Al (Scott Lawrence Kirschenbaum ’03), a self-styled Lothario and lisping Ziggy (Dan Berson ’03) were relaxed and engaging — each separate personalities forming a cogent whole. Under the direction of Thomas Pearson ’01, they swirl around the stage in continuous banter filled with inside jokes, completely removed from the realities of everyday life.

Patsy (Maria-Christina Oliveras ’01), the street-smart waitress and ex-wife of three trumpeters and a podiatrist, is engaging, cutting through the boys’ whimsy with verve and energy.

Perhaps appropriately, the chemistry between Gene and his wife Terry is minimal in comparison with the electricity between Gene and his fellow players. From the start, their relationship takes a backseat to his music. Lauren Popper ’01 is funny and true as the oddly profane yet naive ex-Catholic schoolgirl on the run from a divorce. As time passes and her nickname, “Crazy Terry,” becomes increasingly appropriate, her screaming insanity and constantly door-slamming are less effective. But the closing scenes, in which she is a broken old woman, are gripping.

The show suffered from a few ragged edges; slurred lines, spontaneous slapstick comedy as actors bumped into furniture, spilled water and pictures falling off walls all undermined the continuity of the play. But in each case, the actors recovered from the mishaps with grace and occasional humor.

Side Man

Whitney Humanities Center

Friday and Saturday at 7 p.m. and 10 p.m.


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