LENOX -- Kurt Masur took over the main podium responsibilities in the Koussevitzky Memorial Shed at Tanglewood Saturday night and Sunday afternoon. The former music director of the New York Philharmonic is celebrating the 25th anniversary of his Boston Symphony Orchestra debut, and his soloists this weekend were also longtime friends of the orchestra: pianist Emanuel Ax, who made his debut in 1978, and violinist Joshua Bell, who came along in 1989.
Bell has a young and devoted public -- after all, he was once chosen one of People magazine's 50 most beautiful people -- and he regularly draws longer lines of autograph seekers than any other Tanglewood soloist. On Saturday night he returned to the Mendelssohn Violin Concerto, which he first played at age 12, which means he's been performing it for 25 years. It's still fresh for him, and recently he's been playing his own first-movement cadenza rather than the familiar one most people assume is by Mendelssohn, although in fact most of it was composed by Ferdinand David, the violinist who premiered the concerto. The first half of Bell's cadenza is generic virtuoso noodling and could easily fit into most other concertos, but the second half is a series of ingenious transpositions of Mendelssohn's opening gesture. The rest of the concerto Bell played with many personal touches and a pleasing mixture of finesse and fire. Masur and the orchestra provided a somewhat outsize, overgilded frame.
On Sunday afternoon, Ax came forward in Beethoven's Third Piano Concerto. The key of C-minor for Beethoven means stormy weather, and the pianist left his usual sunny nature behind and came as close to the dark side as he's ever going to come. There was even some grit in the first movement, and a full-scale, high-speed assault on the cadenza before the more predictable warmth in the slow movement and wit in the finale. Beethoven loved long, blurry pedal effects later associated with Impressionism, and Ax unexpectedly supplied some atmospheric ones. Masur and the orchestra were on his wavelength.
Saturday night's symphony was Bruckner's Fourth, the ''Romantic." Bruckner is an acquired taste for most Americans but a venerated cultural icon in Germany, where Masur comes from. He led the vast work with intelligence, experience, and conviction, catching the music's aspirations and inspirations, as well as the unusual mix of head-in-the-clouds and feet-in-this-muddy-earth that characterizes Bruckner's music. The BSO delivered a stunning performance, which was all the more remarkable because these same people had played the equally demanding (and exhausting) Mahler Eighth with James Levine the night before. The horns covered themselves with glory.
So did the BSO strings Sunday afternoon, in the weeping and wailing, waltzing and foot-stomping of Tchaikovsky's ''Serenade." It was a plangent and exhilarating performance, nobly led and warmly played.