Atos Trio. (Gela Megrelidze/Gela Megrelidze)

When I say that a performer plays music as if it sounds new, I generally mean it as a compliment. The Atos Trio, which played at the Library of Congress on Friday night, was unusual in that it made everything sound new in the sense of being different and even odd. When the trio approached Beethoven’s “Archduke Trio,” which concluded the concert, it was with the sense of an alien picking up some seemingly innocuous object, such as a flower, and examining it from every angle with the goal of trying to find out what it could possibly be for.

Most of the music on the program actually was new: Two of the works were “new” in classical music’s everything-written-in-the-past-century-still-counts-as-unfamiliar sense, and one was an actual world premiere. The Atos Trio’s slightly clinical brand of deliberate lyricism stood in best stead in the 20th-century works. The evening opened with Leon Kirchner’s “Trio,” from 1954, which juxtaposes elegiac, quiet beauty — like a crumbling, dried leaf — with more expressive outbursts that grew a little strident at the end. And Ernst Bloch’s “Three Nocturnes,” from 1924, were lovely little bonbons, a sweet interlude between the two biggest pieces on the program.

The main event was the world premiere of Michael Hersch’s “Carrion-Miles to Purgatory,” a 13-part duet for violin and cello based on (or perhaps more precisely evoked by) poetry of Robert Lowell and written, the composer said in a program note, “in response to the death of a dear friend.”

It’s a spare, intense, fiercely inward-turning work made all the bleaker, in the context of this evening, by the removal of the piano’s mitigating flow. Hersch opened and continually returned to string sounds that were straight and jagged: long, wheezing harmonics in measured ­paces, like heartbeats or footfalls, tentative and dogged, marshaling their energies at times for violent and slashing blows of bow on string. It’s a piece that’s staking out a territory, each section like a building block, defining a space in conjunction with the other blocks around it, about the relationship between one micro-section and another.

It’s a delicate and difficult piece to convey, and I wondered whether the two players made it more strident than it needed to be, playing down the spare tenderness of the quieter moments.

When the trio played together, it was Thomas Hoppe, the pianist, who gave it a lissome touch; the two string players, Annette von Hehn and Stefan Heinemeyer, had a hard-edged approach and sounded, even in Beethoven, as if they were making things more difficult than they needed to be. Hersch’s piece is a significant meditation on life and death even without the contextualizing frame of Lowell’s wintry words; and a performance with a more lyrical touch might intensify the poignancy as well as the abrasion.