Heppner trying on Siegfried in Aix-en-Provence (AP)

AIX-EN-PROVENCE, France - When tenor Ben Heppner wanted to try the grueling role of Tristan for the first time back in 1997, he chose a spot that he described as "off the beaten path."

Those first performances in Seattle were a huge success, and he has gone on to portray the hero of Richard Wagner's "Tristan und Isolde" in opera houses around the world.

So when Heppner decided to take on another Wagnerian role notorious for its difficulty -- the title character in "Siegfried" -- he didn't do it in New York, Vienna or Paris, but at the annual summer festival in this town in southern France.

His performance at Saturday night's premiere was in some respects a triumph and in others a work in progress.

For sheer visceral excitement, nothing beats the sound of Heppner's lean, muscular high notes cutting through the orchestra at full volume -- and this orchestra was the Berlin Philharmonic, one of the finest in the world. The freshness and vigor of his declaration of love to Bruennhilde near the end of Act 3, "Sei mein, sei mein, sei mein!" ("Be mine!") resonated through the Grand Theatre de Provence with thrilling clarity and punch.

That this came at the end of a long night -- three acts, each lasting more than an hour, with his character rarely off stage -- made it even more remarkable.

Heppner showed his newness to the part a few times: too much eye contact with the conductor early on, one or two missed entrances, a bit of holding back in the sword-forging scene. In Act 3 there were a few rough patches in the middle register when he had to sing softly, the only hint of vocal fatigue.

It's ironic that Wagner wrote the role of his young superhero with such strenuous vocal demands that it can be sung only by a tenor whose voice has fully matured, typically in early middle age. Heppner, a 52-year-old Canadian with a bulky physique, is not going to make anyone think he's a teenager, but he runs about the stage energetically and assumes a wide-eyed innocence that helps make him believable.

He's aided by costume designer Thibault Vancraenenbroeck, who has dressed him casually in a plaid work shirt hanging loosely over a green undershirt. This contrasts with the more formal trench coats worn by most of the other male characters.

Heppner is coming in, as is his character, midway through a new staging of Wagner's four-part "Ring" cycle in a production by Stephane Braunschweig that's conducted by Sir Simon Rattle. It's being introduced one opera per summer at Aix and then shared with the Salzburg Festival.

"Siegfried" continues Braunschwieg's concept of interpreting Wagner's epic music drama as a dream, though exactly whose dream isn't always clear. As the curtain rises, Bruennhilde is stretched out asleep across three red upholstered chairs, where we left her at the conclusion of the previous opera, "Die Walkuere." The magic fire that protects her from all but the bravest hero is visible in flames projected on the rear and side walls of the set.

The chairs are the same ones on which Wotan was dozing when he first appeared during the initial opera, "Das Rheingold."

Bruennhilde disappears before the action begins, but her brief appearance suggests that she dreams all that is about to unfold of Siegfried's adventures as a young man. If that's true, then do Siegfried and Bruennhilde really unite at the final curtain, or is that her imagination as well?

Sets are minimal, dominated by giant walls that shift position depending on the scene. The forest of Act 2 is just a stand of trees with bare branches at the rear, but a rich shade of green washes over the stage when Siegfried muses about the beauty of nature. (His mother, Sieglinde, makes an unscripted appearance in this scene as her sings of his loneliness.)

The cast supporting Heppner is first-rate. As Bruennhilde, the Swedish soprano Katarina Dalayman sings with great warmth and vibrancy, and the high Cs that are such a crucial ingredient of this role peal forth with uncommon brilliance.

A fine singing actor in the role of Mime, the conniving dwarf who has raised the orphaned Siegfried, always threatens to steal the show for the first two acts. German tenor Burkhard Ulrich is definitely in their ranks. The tall, angular Ulrich, with his spectacles and bald head, looks more like a mad scientist than a cringing dwarf. Vocally he captures every detail of the tricky, high-lying part, including a maniacal cackle.

As the Wanderer (Wotan, king of the gods, in human disguise), Sir Willard White shapes his lines with nobility and beautiful tone. The Jamaican-born bass-baritone occasionally gets overpowered by the thick orchestrations in Act 3, but he anchors the production with his dignified, world-weary presence.

Dale Duesing, an American bass-baritone, has a voice that's frayed on top, but he makes up for that with his fierce presence as Alberich, Mime's brother; German bass Alfred Reiter sings the lines of the dragon Fafner with aplomb; Swedish contralto Anna Larsson displays an impressive range and velvety voice as Erda, the earth goddess, and German soprano Mojca Erdmann sings sweetly as the forest bird.

Under Rattle's spirited guidance, the Berlin players revel in the vast variety of colors in the score, creating shimmering, delicate textures for the forest scene and outbursts of thunderous intensity for the climactic moments in Act 3.

Heppner is due to reprise the role of Siegfried in the final "Ring" opera, "Goetterdaemmerung," at next summer's Aix festival, with performances of the complete cycle to follow.

By waiting until relatively late in his career to take on these roles, Heppner can probably expect to perform them for only a decade or so before time and nature take their toll. Opera lovers will count themselves lucky to hear him for however long he can sustain the golden sound he brings to this magnificent music.

( 1/2This version CORRECTS Tristan to Siegfried in headline. 3/4)