Perennially hailed for performances full of intensity, joy and a fresh perspective on chamber repertoire, Seattle's Onyx Chamber Players will be capping its current season on Sunday at Town Hall.

The group's transatlantic program, "Music from America and the British Isles," focuses on two 20th-century iconoclasts and a world premiere by one of Onyx's founding members.

Benjamin Britten's 1933 Phantasy Quartet for Oboe and Strings, written at age 19 by the English modernist, shares a bill with Connecticut-born Charles Ives' 1904-1915 work, Piano Trio. Pianist David White will introduce his own Piano Trio, a new composition, with Onyx partners Meg Brennand on cello and James Garlick on violin.

Typically, Brennand, White and Garlick — all current or past ubiquitous figures in the Seattle music scene — are overcoming geographic hurdles for the show and its demanding preparations.

"We prefer an intensive approach, an almost festival-style rehearsal schedule," Garlick says. "We live in different cities but come together to work hard toward a unified vision."

Garlick, 28, who joined Onyx three years ago, is a Port Angeles native who serves as concertmaster for Northwest Sinfonietta and has played with Seattle Baroque Orchestra and Cascade Symphony.

In New York, where he completed his master's degree last month at Juilliard, Garlick has already made his Carnegie Hall concerto debut and performed with the New Juilliard Ensemble, the chamber ensemble AXIOM and the Salomé Chamber Orchestra.

He speaks with infectious enthusiasm about Ives' Piano Trio.

"He's a grandfather of modern music, but he's also full of humor and transcendent beauty. He read lots of Thoreau and Emerson. He has fun, but arrives at a spiritual place."

Onyx's musical mission, White says, "is to play from the composer's viewpoint forward, to recapture the dramatic impact of hearing music in its original incarnation. Even though we play on modern instruments, we've always played music with a stylistic performance appropriate to a given period."

White, 53, has long been in demand as an accompanist, organist, conductor and composer. He founded Onyx over a decade ago but moved to his hometown Chicago during the group's second year.

White composed the new, five-movement Piano Trio in memory of his late brother, Joseph.

"He was such a shining light, I deliberately wanted the piece to be as un-requiemlike as possible," says White. "There's a sunniness and insistent optimism about it."

Brennand, 50, is a respected and visible musician in Seattle, a member of the Pacific Northwest Ballet Orchestra, Seattle Baroque Orchestra and Capella String Quartet.

Describing how Britten's piece begins with a low pulse on cello, Brennand says the Phantasy develops "inviting, different structures.

"But it's all very luscious, especially the oboe, adding a wonderful, enveloping sound."

What is unique about Onyx, Brennand says, "is that it is nimble enough to go anywhere, sometimes reinventing the way classical music is presented. It is music-making that is alive and mercurial, almost hallucinogenic."

"Playing chamber music is my first love," says Garlick. "Being in a long-term chamber ensemble with three personalities really working together, where every concert and each season can be something more and more, is a wonderful experience."

Tom Keogh: tomwkeogh@gmail.com