There is a special fascination in the Metropolitan Opera's "Rigoletto" as it comes around on tour every few years. By now in its long performance history, all traces of any original directorial concept have been worn smooth and it is the property of the performers to do with as they will, in harmony or in wild disagreement. To veteran Met-observers, it is almost as familiar as a favorite restaurant, but on each return one never knows quite what to expect.

One thing this production has done through the years is prove that "Rigoletto" is almost indestructible. Given any kind of chance, the music and the melodramatic plot will work on all but the most jaded members of the audience.

This year's one-night-only performance might have been billed as the "No-Star Rigoletto," except that that would hardly have sold tickets. Given last night, it proved once again the almost foolproof power of Verdi's masterpiece. The performers didn't intentionally do anything to harm the music, but only occasionally did they do much to help it. No matter; it worked.

It might be called a cool "Rigoletto" -- but even in a cool performance, this opera remains red-hot.

One of the performers may have been putting out extra effort: Aldo Protti, making his Met debut in the title role long past the age when most singers have retired. It is hard to judge his level of effort, because at this stage in his career his vocal and dramatic powers are severely limited; he may have been working hard when he seemed to be just drifting.

Otherwise, the "take it easy" style was set right from the beginning by tenor Dano Raffanti, whose "Quest' o quella" earned an epithet that can rarely be aplied to that aria: effortless. And -- surprise! -- it was refreshing, for once, to hear a singer jogging easily through an obstacle course that has broken the hearts, strained the vocal cords and shattered the careers of so many who have tried to do with it a little more than they could. The effect was less athletic than usual, but considerably more musical. Raffanti is a most promising young tenor -- promising, above all, because he seems to recognize and accept his limitations.

He maintained the same style throughout the evening until just before the end, when he hung on for what seemed like 15 minutes to the last high note in "La donna e mobile." The aftermath proved the wisdom of his basic strategy; the few fragments he had to sing after that showed a serious falling-off in his vocal control. But it no longer mattered; he had done what he had to, done it with good tone and fine musicianship, and earned the warmest applause of the evening at the final curtain.

Gail Robinson sang a neat, professional, unadventurous Gilda. Isola Jones was largely wasted in the small role of Maddalena but, in the circumstances, didn't seem to mind. The real strength of the Metropolitan Opera may lie actually in the quality of the people it is able to throw into secondary roles: John Macurdy, for example, as Sparafucile and John Darrenkamp as Marullo.

Conductor Nello Santi may have been working against the general easygoing flavor of the performance by setting a brisk pace through much of the opera. The resulting orchestral vigor (particularly with an orchestra as fine as the Met's) enhanced the kinetic energy already put into the music by Verdi and probably contributed more than any other single factor to the music's overall impact. He conducted the singers (when they would let him) as knowingly as the orchestra -- notably in the Act 2 duet of Gilda and the Duke, where he led Robinson and Raffanti through the music's thickets phrase by phrase, almost note by note, with precise and effective gestures.

The basic set is a three-tiered sort of tower (something like an eccentric wedding cake and something like a medieval conception of the Tower of Babel). Since the last time this production appread on the Kennedy Center Opera House stage, it has been utterly eclipsed, on the same stage, by the sets and costumes of the Washington Opera's "Rigoletto" -- perhaps the finest setting for this opera now available anywhere in the world.