Philomusica Quartet, with guest violist Erin Pipal

Monday night, the Philomusica Quartet’s thrilling rush to the climax of the first movement of Mendelssohn’s Opus 12 String Quartet flowed naturally from the players’ clear, confident reading of everything up to that rush. They knew where the first movement was going, and they knew just how to ride Mendelssohn’s gestures, melodies and harmonies over the top.

This grasp of big structures gave purpose and drive to all four of Mendelssohn’s movements, singly and collectively. A single arc encompassed that explosive opener, the rustic ballad of a second movement, the ardent singing of the third and the furious rush of a finale, with its wild running sextuplets near the end. Violinists Jeanyi Kim and Alexander Mandl, guest violist Erin Pipal and cellist Adrien Zitoun staged-managed the denouement with special grace. At the very end, when we energy and possibility seem exhausted, Mendelssohn placed a poetic recollection of the introduction. The Philomusica made it sound like a memory of a lost eden.

In his String Quartet No. 3, Opus 73, Shostakovich twists familiar things into odd shapes, in the way of dreams and surrealism. The opening theme, for example, reads immediately as a blunt, simple country dance, and you await the repetitions. They never come; while the tune maintains its antic, bumpkin personality, it wanders drunkenly through an open-ended unfurling. The players got the essential goofiness of it and made me laugh. Dreams can be scary, too; thus, the vicious rip-off-the-strings march and creepy waltz in the second movement, the machinery gone mad of the third, and striving violin ascents dragged down by trailing descending lines in the fourth. Like Mendelssohn, Shostakovich looks back to earlier material in his finale, but with a more jaded eye. Again, Kim, Mandl, Pipal and Zitoun felt the drama as one, and their assurance with impulse and sentiment resulted in well-tuned, confident, expressive playing loaded with nuance.

Their reading of Beethoven’s massive and massively complex Opus 127 was not on that level. They went in and out of focus throughout. Ensemble frayed here and there, uncertain balance made for murky textures, and pitch drifted. These readily identified technical flaws do not reflect lack of ability; the players showed great ability in the first two pieces and on any number of prior occasions. The flaws were symptoms of interpretive uncertainty. They were like actors who knew the lines but weren’t quite settled in the direction of the scene. When that happens, actors and musicians alike ramp up the energy, always with diminishing returns. So, for example, you end up with an impression of desperate haste rather than exhilarating speed in the scherzo.

Even with all that, this was not a bad performance. The crowd at the Wisconsin Conservatory of Music, where the quartet is in residence, returned a nice ovation for the hard effort. But the Philomusica is capable of a more compelling Opus 127. They just have to live with it a little longer.