Daniel Barenboim; photo by Karl Schoendorfer/REX, via the Daily Telegraph

There was a Wagner concert in the Great Festival Hall at the Salzburg Festival last night. Daniel Barenboim led the West-Eastern Divan Orchestra and a cast of veteran singers in the Prelude, Act II, and Liebestod (“Love-Death”) from Tristan und Isolde. The festival gave this concert an intriguing name: “The Tristan und Isolde Project.” But people have been performing exactly this program from time immemorial. It’s what you do when you want to give a Tristan concert.

I’d like to tell a story. Some years ago, I attended a Tristan at the Metropolitan Opera. Barenboim was in the pit. He was conducting very badly, or indifferently. It was like he had simply not shown up. During the second intermission, I made up my mind to leave. But I had gotten separated from the friend whom I had taken to the opera. So I went back to our seats to tell her I was leaving. She argued that I should stay. And then the lights were dimming. So I had no choice but to sit down.

And, in Act III, Barenboim was enthralling—entirely engaged, entirely musical, spellbinding. Why? Why then and not before? I don’t know.

Last night, Barenboim was very good—superb—from the beginning. The Prelude was very slow—probably the slowest I have heard—but it never dragged. It breathed beautifully and compellingly all through. He was no less good for the rest of the evening. This was the conducting of a podium master.

The orchestra was not good, or maybe I should say not first-class. The West-Eastern Divan Orchestra is a cultural-political effort, an orchestra made up of Israelis and Arabs. On purely orchestral merits, the West-Eastern Divan Orchestra would probably not get a gig like this. But people support the idea behind the orchestra, understandably.

It occurred to me that Barenboim needed to try harder, or conduct better, because of the quality of the orchestra. Again, I don’t know.

The singers were placed behind the orchestra, on risers. They were quite a long way from the audience. They might have been better off in front of the orchestra, as they traditionally are.

In the role of Isolde was Waltraud Meier, the German mezzo-soprano. Isolde is a soprano role, but mezzos dip a toe in—Christa Ludwig made a famous recording of the Liebestod. And Meier, as a singer, is a bit of a ’tweener: a soprano / mezzo-soprano.

The great Meier had very little voice to give. And what voice she had was not in good shape. She struggled, with intonation and everything else, throughout the night. She had zero high notes. Everything high was flat. Did she have enough musical intelligence and wiles to make up for the absence of a voice? That would be practically impossible: You really need an instrument in the part of Isolde.

Like Meier, our Tristan, the German tenor Peter Seiffert, had little voice to give. He, too, had a struggle throughout.

So, this was the situation: In some of the most beautiful music ever written, no one—neither the soprano (or mezzo) nor the tenor nor the orchestra—was making a beautiful sound. That was a problem.

Eventually, King Mark came on, and he was the best King Mark of our time: René Pape, the German bass. He came on with his water bottle. Why do singers in concert think they must have water with them at all times? They don’t in opera. Anyway, Pape sang like the best King Mark of our time. He contributed total authority.

In the Liebestod, as in the score at large, Barenboim was alert and kind: He took the singer’s final measures at lightning speed, knowing she was out of gas. Then he slowed down, to deliver the orchestra’s closing pages beautifully, transcendently.

A customer pays a lot of money when he attends a performance at the Salzburg Festival. What did he get last night? He got superb conducting and a superb King Mark. Otherwise . . .

Daniel Barenboim is one of those mysteries. He can conduct or play the piano like a dog—like a pigheaded amateur. And he can conduct or play like an all-time master. This is one of the things that make musical life interesting, I suppose.

I will end on a meteorological note: It has been very cool in Salzburg. Last night, the temperature was maybe 55 degrees. And inside the Great Festival Hall, it was sweltering. I’m surprised the audience didn’t drop like flies. The heat inside the halls—no matter the weather outside—is part of the Salzburg experience.