Portraits of Beethoven tend to show a rather gruff, forbidding individual, with no laugh lines etched into the face.

And that stereotype too often influences performances of Beethoven's music, presenting a humorless image of the composer shaking his fist at life.

A very different view of Beethoven emerged on Sunday afternoon, in the latest recital of the Schubert Club's Music in the Park series.

The artists were the Danish String Quartet, currently on tour in the U.S. They opened their concert with Beethoven's String Quartet No. 2, and it felt like a breath of spring air.

This is a young string quartet — the players are all in their early 30s — and you sense it in the blithe, unsullied optimism of their playing. The opening Allegro movement was delectably nimble in articulation, with an airiness of manner and a playful, witty reaction to Beethoven's busy rhythms.

Rune Tonsgaard Sørensen was particularly prominent. His sweet, singing tone was a constant source of pleasure in the chirruping decorations Beethoven wrote for the first violinist. Sørensen was matched by his fellow players in a scampering, featherlight traversal of the Allegro molto finale, which sparkled with vivacity and joie de vivre.

Much of that elegance and lightness of touch carried over into the main challenge of the afternoon: Beethoven's String Quartet Opus 130, one of five quartets dating from late in Beethoven's life, all masterpieces of the genre.

So many performances of this extraordinary composition seem ponderous and overly reverential. From the outset, though, the Danish players brought freshness and lucidity to bear with their flowing, purposeful account of the discursive opening movement.

In the famous "Cavatina," the players again avoided lingering sentimentally, making the profundity of this beautiful music all the more obvious. Immaculate balancing between the four instruments seemed to cut the music loose from earthly cares and worries, to some higher region of philosophic contemplation.

For the finale, the Danish players opted for Beethoven's first and vastly more difficult option: the immense, 15-minute "Grosse Fuge" his publisher persuaded him to replace with a shorter movement, because he thought audiences (and players) wouldn't understand it.

The Danish String Quartet's performance vindicated Beethoven's original intentions. The fugal material was etched with sculptural clarity, without the overemphasis often resorted to in this already highly charged music.

Between the Beethoven pieces came the Third Quartet of Russian composer Alfred Schnittke, which used themes from Beethoven's "Grosse Fuge" and a vocal work by Renaissance composer Orlande de Lassus.

The Danish players' acute ear for texture and pin-sharp intonation drew evocative echo-chamber effects from Schnittke's writing, as musical voices from the past spoke through the centuries to an anguished present.

It was an intense performance, but it was the Danish String Quartet's life-enhancing, at times transcendent Beethoven that lingered longer in the memory.

Terry Blain writes about classical music and theater.