The Artemis Quartet comes from Germany — Berlin, to be specific — and they are highly decorated, widely praised. On Wednesday night in Zankel Hall, it took them a while to live up to their reputation.

They played three string quartets, or rather, two of them, plus a fraction. They began with Webern’s “Langsamer Satz,” or “Slow Movement.” You might consider this a cousin of Mahler’s “Quartettsatz” (“Quartet Movement”) — just a fragment, but somehow complete, and definitely wonderful. Webern wrote his piece when he was in love; and it is a thing of sighing, startling beauty.

Earlier this season, we had an excellent — I’m tempted to say perfect — performance of the “Langsamer Satz” by the Daedalus Quartet, in Alice Tully Hall. You sort of held your breath, all the way through. The piece was angelic, ethereal, pure.

The Artemis didn’t play it this way, which is fine. They played it passionately, boldly, into the strings. Lots of portamento, lots of bigness. I think the piece should be lighter, sweeter, and more exquisite — less passionate and more marveling. More grateful, even. But, again, an ensemble is entitled to its approach — although it should play cleanly, no matter what. The Artemis was on the sloppy and scruffy side.

Nonetheless, the “Langsamer Satz” made its mark. You can’t quite defeat this immortal fragment.

The Artemis next turned to Beethoven, one of his middle-period quartets, that in E minor, Op. 59, No. 2. This is one of the “Razumovsky Quartets” — and Count Razumovsky, you will remember, was Russia’s ambassador to Vienna and a violinist. Most important to history, he was one of Beethoven’s best patrons. And he commissioned the three quartets of Op. 59.

In the first movement of the quartet they played, the Artemis was sensible and unobjectionable. But they were not musically arresting. The sound they made was neither beautiful nor ugly. It was grainy, unfocused, a little dull — just there. And intonation was on and off.

It seemed there would be no polish on this evening (though polish isn’t everything in a musical performance, far from it).

Beethoven’s second movement is sublime, quasi-religioso, and the Artemis might have given it more warmth. But the players kept a steady pulse — very important — and did nothing extreme or weird. I should note that the violist, Volker Jacobsen, played some beautiful low passages — these were almost cello-like.

The third movement, Allegretto, was ably negotiated, although it could have been more high-spirited, more “unbuttoned,” to use the familiar word (the word commonly applied to this type of Beethoven). And the last movement — Presto — was largely a success. The players were smart and jaunty, almost saluting, or mock saluting. Unfortunately, the first violinist, Natalia Prischepenko, suffered some bad intonation.

The second half of the program brought us a colossal work, Schoenberg’s String Quartet No. 1 in D minor. This is not to be confused with the Quartet No. 2 in Fsharp minor, which uses a soprano, and texts by Stefan George (“I feel the air from another planet”). The Quartet No. 1 is in four movements, all of them marked, but there are no breaks between them, allowing us to say that the piece is in one movement.

My bit of cheek aside, this is a great work, as the Artemis Quartet made unmistakably clear.

They played with true understanding, and they also played straightforwardly. They didn’t try to do anything, particularly, to the music. They simply let it unfold. They employed all the various sounds needed to express Schoenberg’s ideas: now lush, now bleak. One fluttering effect was amazing.

But there was an “incident,” as the police say. The group was motoring along when a loud pop occurred — Ms. Prischepenko had broken a string. Off she went to do the necessary repair. The other three simply sat and waited, as did the audience. Back she came, and the group, and the music, resumed without any problem, without any awkwardness. The playing was intense, focused — excellent.

I would submit it’s not easy to hold interest all through this work (45 minutes), particularly with a break for a repair job. But the Artemis did so. And they made good on their high reputation.