The singer Kurt Elling projects in strong, concentrated gusts: a half-second of inflation and then the word itself, drawn out and oversized. He can sound like a horn, and works in long, free-ranging solos, sometimes making that process literal by mimicking actual solos in word-based "vocalese," after the manner of Jon Hendricks.
Few other jazz singers have his Coltrane-like command over a long, droning note, and he revealed that power several times in a succinct and powerful set at the Allen Room in Rose Hall on Thursday night, a double bill with the singer Luciana Souza.
Mr. Elling began with the standard "More Than You Know," with a trio directed by his pianist Laurence Hobgood, and then went through a long adaptation of Grover Washington Jr.'s "Winelight," with his own lyrics. Mr. Elling uses microphone technique to strengthen his communication; he drew it closer or pushed it away as he needed, and he found great momentum. At a certain point in the "Winelight" solo he had said his piece, yet kept on going anyway. He laid in tricks that he hadn't quite built toward, starting a growling-drone passage, and then a rapid, machine-gun set of short scat syllables.
The poet Robert Creeley - who died on Wednesday - was honored during a lull in the middle of Mr. Elling's song "Man in the Air." Reciting Mr. Creeley's "Signboard" over sparse accompaniment, he made the audience ignore the city lights through the high glass window behind him and focus on a short, hard, unmannered poem, before a drum solo. And before ending, he explored another good, intuitive idea: singing "In the Wee Small Hours of the Morning," over an arrangement based on Keith Jarrett's delicate instrumental trio version of the song. The less specific Mr. Elling is about what he's attempting, the better he gets.
Ms. Souza uses poetic texts as well but has a tidier and quieter style: she never gets anywhere near Mr. Elling's level of volume, and her precise pitch grows likably vulnerable in the middle of her alto voice. Her band plays more tightly scripted arrangements, and she sang some poems by Neruda, backed by her own ambitious composing, a progressive jazz-into-pop style; she also sang a few songs by Antonio Carlos Jobim in Portuguese.
Her use of text has been quite careful, but she may be getting freer. One of her new pieces, "Poetry 101," collided small portions of different poems - four lines from Elizabeth Barrett Browning, a few from Neruda and Robert Frost, the beginning of Elizabeth Bishop's "One Art."