Backstage, the stage hands of the Royal Opera are discussing Robert Wilson's forthcoming production of Verdi's Aida. The Egyptian opera, a tragedy that pits the grandest passion against the gravest politics, is a staple in the repertoire of the world's opera houses, and the death scene, in which Aida and her lover, Radamès, are sealed in a cave, is one of Verdi's greatest set pieces.
"It is," says one stage hand, "a very conceptual cave." "Oh, a very mental cave," joins the other.
"It's another smash hit for Drury Lane!" And, of course, it is. Wilson is a draw. His Aida, which was unveiled last year in Brussels at La Monnaie, sold out months in advance of its Covent Garden opening. His staging for the Royal Academy's current Armani show is causing as much interest as the clothes themselves. Last month, his Temptation of St Anthony at Sadler's Wells broke, said critics, yet another mould. With such a Stakhanovite work rate, it's astonishing that Wilson, now 61 and with a greater wealth of productions (and honours) under his belt than any other working director, is only now making his debut at Covent Garden.
It may be a little tiring to repeat the usual superlatives applied to Wilson - the most avant-garde, the most influential, the greatest director - although for once they're probably true. But to the superlatives, one could also add that he is the most attentive. For an artist whose work is so much associated with light ("Without light, there's no space," he states), he's also big on noise. Simply, Wilson makes his listeners aware of how noisy the world is. "I start any work the same way," he says. "I start a rehearsal with silence. John Cage said there is no such thing as silence, there's always sound. So we listen. Theatre for me has to be about one thing first, or it gets too complicated.
"Listen," he commands, and we do. "I hear the traffic outside; I hear you sitting up; I hear the air conditioning; I hear my foot on the carpet. That sequence of sounds will never, ever, happen again. The only thing that's constant is change." It is this immense subtlety of movement - light, sound, intention - that informs all Wilson's work. There is nothing superfluous in his rigorously uncluttered staging, something that's necessary to allow a clear focus on complex activities. One of Wilson's most profound influences was the psychologist Daniel Stern. Stern filmed mothers and babies in natural situations; the baby would cry, its mother would comfort it. "But," Wilson says, "when the film was slowed down, and there were 24 frames per second, you'd see another story." He pulls the face of an enraged mother, a terrified baby. A single second could contain rage, love, terror. This most basic ambivalence continues to fascinate him. If Aida is about love, then it's also about hate. "They are part of one world. Heaven can't exist without hell. If we stay open to that, then we have a different experience." His theatre is formal, he stresses; it is not interpretative. "In formal theatre, there is room for reflection. You approach the work with a question: what am I saying? What am I doing? If you know what you're doing, don't do it." Be careful, he warns, about imposing any one meaning. Sometimes there are no meanings, which is not to say that an action is meaningless. "My responsibility is to ask what it is, not say what something is." It's vital, in Wilson's framing of the opera, that there is room for reflection. With its wider themes of war and imperial ambition, Aida has a grim political contemporaneity, and Wilson reflects this in his production.
"I try to present something that is full of time. Not timeless, but full of time. I never like a work where we try to update it, but it's still not interesting to see a work that is dated. If one is successful, then a work can be full of time. And time is very complex."
That his style, or at least its surface elements, seems to be so well understood, delights the director. But critics carp that Wilson, originally trained in architecture and fine art, subjugates source material to his own design. It's all lights, two-dimensional movement, a controlled spectacle. "It's true!" he laughs. "They're right! But, I tell you: opera means works. It's plural, so it's everything. It's psychology; it's architecture, it's light. It's not just music - and that's what's exciting.
"I had dinner with Marlene Dietrich in the early 1970s," he remembers. "I went to pick her up and she had someone with her, a dreadful man. He was writing a book about her, and he said to her, you're so cold when you perform, and she said," - here Wilson concentrates his tone with a low menace - "'You didn't listen to the voice.' She said the difficulty was to place the voice with the face. She could be icy cold with those movements and the voice could be hot and sexy, and that was her power.
"So if you get this music fired up," Wilson concludes, "and the singers walk against it, and [don't] step on the beat of the music, like a high school marching band, that's what'll create the architecture, the tension between what I'm hearing and what I'm seeing. What I'm seeing can help me hear better."
'Aida': Royal Opera House, London WC2 (020 7304 4000), 8, 11, 14, 17, 20, 22, 26 and 28 NovemberReuse content