In the tradition-bound world of classical music, new music is working hard to carve out its own ensembles and traditions and tropes. One of the new roles that’s emerged is contemporary cello goddess. The Bang on a Can All-Stars, one of the granddaddies of the current alt-classical scene, has had three cellists since its founding in 1992, all with notable solo careers: Maya Beiser, now an indie-cello star; Wendy Sutter, who inspired several recent cello pieces, including a concerto, by her then-boyfriend Philip Glass; and Ashley Bathgate, its current cellist, who brought a program of solo cello suites, “Bach Unwound,” to the Strathmore Mansion on Thursday night.

Bach’s six solo suites are the cornerstone of the cello repertoire, the most evocative and recognizable and profound of solo cello works. In this project, six composers who are members of another new-music collective, called Sleeping Giant, each composed a new piece based on one movement of one of Bach’s suites to create a new suite that’s also conceived as an evening-length concert work.

The dialogue between past and present is productive and fertile terrain in the music landscape, and plenty of people mine it; composers have been tackling Bach-like cello suites for years. The challenge, of course, is that putting new work up against an established masterpiece — a piece as familiar to many listeners as the whorls of their own fingerprints, which is to say taken for granted while always capable of being seen freshly — is hard on the new work, which has to be instantly timeless or suffer in the comparison.

In this context, it was hard on the old work, as well. Bathgate opened with Bach’s first suite, played with a bright brassiness that gleamed like a facade over the music, but with a kind of sameness: this was, after all, only setting the stage for what was coming.

The six composers of the Sleeping Giant collective met while students at Yale, and in a way their music was a little too smart for its own good, each piece proceeding from, and engaging with, a good idea about Bach. Chris Cerrone, for instance, thought a lot about pedal tones, with long, drawn-out notes colored with echoes and reverb, giving a sense of the music being eaten away from without. Ted Hearne, ever iconoclastic, took the music from a television ad for a rent-by-the-hour hotel chain that he remembered from his childhood, and used it as a thematic base for his work, juxtaposing real music with a kind of music product, jingly sequences of sound effect that had nothing to do with art, like a Jeff Koons balloon dog. And with “Orison,” the final piece, Robert Honstein used computer extension of the notes to set up a hall of illusions in which it was hard to tell where the “real” cello ended and the enhanced sound began.

Bathgate introduced this project in 2016, just around the time she last appeared in Washington on a stunning but underattended concert. This outing, by contrast, was nicely filled but far less formal; the easygoing vibe conveyed the impression that this new work had taken on the informality of a favorite outfit, reasonably flattering, but a little rumpled after frequent use.