LENOX — Esperanza Spalding contains multitudes. At her most creative, the charismatic artist doesn’t so much cross over from jazz to pop as she refracts genres into little slivers that play off each other. Once upon a time in the 20th century, her contemporary R&B effort “Radio Music Society,” released last year, would have prompted a surplus of critical angst over whether or not it’s really jazz. But today, in no small measure because the jazz world can really use a superstar of Spalding’s beaming appeal, it’s all fair play.
But she made little effort to woo the casual fan in concert at Tanglewood’s Ozawa Hall on Sunday night, the last stateside date supporting that 2012 album. Featuring Spalding plus an 11-piece band (complete with robust brass section), it resembled no concert I’ve recently seen, in the extent to which Spalding invited — required, really — the audience to join her in a self-contained space, where tune after tune unfurled into multi-colored essays that amounted to a delicious slow burn rather than a series of climaxes.
From the opening tune (a slowly congealing “Radio Song”), Spalding whipped her band into a sultry churn, teasing out emotional accents in a deeply textured performance. It was a series of engrossing, if insular, mood poems spiced by plenty of musical virtuosity.
Spalding alternated between basses, authoring deep-grooved riffs on the electric and dexterous, spidery solos on the acoustic. Her assured vocals rarely stole attention from the rest of the musical business, though she did cut loose on an encore duet with pianist Leo Genovese, confidently scatting her way through a song she claimed she’d bungled the day before at the Newport Jazz Festival.
In banter that sounded well practiced, Spalding frequently addressed the audience as if it were an ex-lover she was lobbing the songs at, a move with a weirdly distancing effect. But it also added context to moments like Tia Fuller’s eloquent, agitated saxophone solo in “I Can’t Help It,” bending the song’s outburst of dizzy infatuation into a frustrated lament.
Or “Smile Like That,” where a flowing instrumental dialogue between Fuller and guitarist Ricardo Vogt was crashed by Brian Landrus’s interweaving lines on tenor saxophone, suggesting the looming presence of the third member within a love triangle.
“You sure do sound good together,” Spalding quipped, entirely blurring any distinction between the song’s lyrical narrative and the chops of her excellent band. A musical argument never sounded so harmonious.