The Three Tenors, a very popular form of stadium entertainment involving the amplification of the male voice, came to MCI Center last night, the second stop on their 10th-anniversary world-saturation tour. If ticket sales didn't completely tank--the house looked about two-thirds full--they certainly dipped, and the big news of the Washington performance is that perhaps this franchise is no longer golden.

The tenors themselves, Luciano Pavarotti, Placido Domingo and Jose Carreras, sounded just about as good as one can expect from men their age. Domingo was in very fine voice; Pavarotti was a bit pinched but marshaled his resources carefully and brought down the house with his signature aria, Puccini's "Nessun dorma"; and Carreras, whose voice never completely came back after his bout with leukemia in the 1980s, sang several popular songs with more than a hint of the golden tone he once had. And, except for one peevish man who shouted something about the lights, everything ran smoothly--amplification, illumination, entrances and exits--all of it orchestrated down to the last detail.

But it was an act of mercy to darken the house before the tenors took the stage. No point in making the audience realize what the show's mercenary impresario, Tibor Rudas, must be wondering right now: Why don't more Washingtonians love the Three Tenors at the $600 price point?

Thousands of seats remained empty, especially in the expensive rows closest to the stage, and the most crowded part of the stadium was behind the singers, where people who could afford only 50 bucks a pop sat and watched the tenors' bald spots glisten in the dazzling light.

When Pavarotti, Domingo and Carreras first sang together in Rome in 1990, they sang for charity. They sang to welcome Carreras back after his illness and to raise money for good causes. Today they sing for money, big stinking pots of it. Nothing wrong with that, except that the unscripted good fun of the original concert has been replaced by the well-oiled-machine approach, and a lot of the charm of the Three Tenors has fizzled away.

Paradoxically, given that the Three Tenors sing in stadiums, their magic has always been the illusion of intimacy. In the first concert, one saw three exotic beasts of the operatic jungle, three men who presumably had healthy rivalries and perhaps some real antagonisms, laugh and yuk it up onstage just like regular folks. There was, in fact, some rapprochement between Pavarotti and Domingo going on that first time around; but that drama has disappeared, and the illusion of intimacy has been replaced by the reality of cool professionalism. Today when they sing, they just stand there with smiles on their faces, interacting only minimally.

The Three Tenors formula is rigid. The singers sing in ascending order of name recognition: first Carreras, who is tolerated like a warm-up act; then Domingo, who actually delivers the artistic goods; and last Pavarotti, who walks off with all the applause. The music is carefully chosen for each of their voices, never anything too long or taxing, and, perhaps because of the acoustics, nothing that moves very quickly. There was not one good rousing cabaletta on last night's program.

Amplification is essential to the artistic product, and it reverses the usual dynamic in the reproduction of classical music. In that world, engineers try to make recordings sound like live performances; here, however, the engineers are trying to make the live performance sound more like a Three Tenors CD in your living room. The voices are boosted above the orchestra, where they float with surreal strength and clarity. Tenors and orchestras never really sound this way, but that's not the point; nobody pays to hear the orchestra (conducted last night by James Levine, and not even credited in the program).

In the first five years after the original Three Tenors concert, there were only two attempts to repeat the event, one in Monte Carlo and one in Los Angeles. Since 1996, however, there have been 19 follow-up concerts, not including last night's. The current tour will take the act to Cleveland and finally Albany, N.Y.

If they're playing Albany, Woonsocket can't be far behind. As this cultural phenomenon draws into its twilight years, it's worth looking at its long-term effects.

First, the Three Tenors sucked the life out of the classical recording industry. The financial expectations they created with their multi-million-selling discs created a black hole that finally killed off the last vestiges of socialism in the business. Before the Three Tenors, major record labels looked at profitable recordings as a way of bankrolling more adventurous fare; today, they don't record without the prospect of big profits.

Second, although their concerts may have sparked greater interest in opera, they've been anything but a force for populism in music. Ask the folks who bought the $50 seats in the rafters. Or better yet, try to go to an opera sometime. The problem isn't a lack of audience, it's the cost and limited availability of seats. And the Three Tenors have been in the forefront of rising ticket costs.

But they do entertain people, despite the grand silliness of singing opera in an airplane hangar. Domingo was in his element last night, singing to his part-time adopted home town with evident relish. He gave the audience a silvery and muscular account of Puccini's "E lucevan le stelle," and he alone among the three got the English diction right in the concluding medley of American show tunes.

Carreras works very hard to sound good, and he sounded more robust last night than he has in years. The top voice isn't as pretty as it once was, and he doesn't assay the repertoire he once did. But he never produced a certifiably harsh sound, despite some flagging of energy in the second half.

And then there's Pavarotti, the man who pioneered the huge outdoor singer spectacular (with Rudas's guidance). The voice is still there, a remarkable feat of preservation given his years on the operatic stage. But the wind seems to be out of his sails. Despite the rapturous audience response, despite a still glorious account of "Nessun dorma," the final telling image of the Three Tenors was Pavarotti in the concluding trio: He looked like he wanted to go home. Perhaps the man who started tenor mania has finally had enough.