Something musicians quickly discovered once the COVID lockdown set in for real was that Zoom and similar technology — indispensable if often aggravating for work, school and family get-together — was more or less useless for group performance. The microscopic time lags that pose little or no problem in conversation proved insurmountable to musicians trying to keep a beat.

So Brooklyn composer Judd Greenstein found an artistic workaround: He wrote a stretch of music that doesn’t require performers to stay in strict time. Then he went further and built an entire piece around that dynamic.

The result, “Together,” is at once beautiful and thought-provoking, an elegant 15-minute stretch of sheer sonic pleasure that also comments — wisely and lightly — on the terms of its own creation. It emerged as the high point of the brief, buoyant concert given in Berkeley’s Hertz Hall on Friday, April 8, by the New York contemporary music sextet yMusic.

There’s a recognizable esthetic character to all of the ensemble’s undertakings, which include performances of music written by their composer colleagues as well as the short, vivid pieces co-created by the group members.

这是利用音乐根深蒂固的记忆minimalism, rock and neoclassicism to forge a world of vibrant sound colors and dexterous rhythmic structures. There are repeated grooves and melodic effects that speak of rich joy. The audience is always kept in the loop; the listener’s pleasure is a paramount concern.

At times, the music that emerges can feel a bit thin, as if the bar has been set too low and once it’s achieved we can all go home. Friday’s program, presented by Cal Performances, included some stretches that sounded pleasant but oddly unambitious.

To listen to “Together,” though, was to be reminded how much can be accomplished within this sound world. In the initial establishing sections, Greenstein sets up a collection of distinctive musical worlds, one for each instrumentalist — a rapid flourish for the flute like the song of a fantastical nightingale, harmonically exploratory figures for the strings, and so forth.

Each piece of musical material occupies its own harmonic and rhythmic space, not dependent on anyone else but not entirely isolated either. The gestures interact in a loosely connected way. Each one is, as the saying has it, a mood.

And then, with subtle but sure-footed directness, Greenstein gathers them in for the sequel. Rhythms are increasingly shared; the harmonies allude to one another. “Listen to that,” you think, “they’re playingtogether” — and suddenly, a musical attribute that has always seemed a basic requirement begins to feel like a radiant achievement.

The rewards of the rest of the evening were genuine but more evanescent. “Tessellations,” by the Berkeley-born composer Gabriella Smith, trades in crisply layered rhythmic patterns — begun by the cellist tapping a catchy beat on the body of the instrument — that shimmer and shift beguilingly, like something out of ’60s op art. But after four minutes — just when the listener is ready for something to be built on that foundation — Smith abruptly clocks out.

In “Ecstatic Science,” composer Missy Mazzoli builds dense harmonies that slip their moorings unpredictably without losing cohesiveness, like a musical lava lamp. Andrew Norman’s “Difference,” which occupied the evening’s second half, focuses in on single notes, comparing their sonorities and later their precise pitches as if examining a series of paint samples. The ensemble’s four short compositions, pop songs without words, boasted a neatly improvisatory feel.

What ran consistently through the concert was the deft, attentive virtuosity of the playing. Like any strong performing ensemble, yMusic is both a vehicle for the thoughts of other composers and a powerful creative force in its own right.