The Metropolitan Opera is a strange paradox. The company seems incapable of putting on a well-cast ''Boheme'' or ''Butterfly,'' but for something as ambitious as Verdi's ''Don Carlo,'' suddenly a rally occurs and the results are a surprisingly satisfying evening of opera.
It could easily be argued that a better cast could be assembled, or that a better staging would be worthy of the Met. Radio listeners will be able to judge for themselves March 26 (check local listings for time). Next season, TV viewers will be able to see for themselves. The performance was never less than highly competent, and in several cases, quite distinguished.
At the very top of the honors list must come Placido Domingo in the title role. The tenor is not always at his best: In roles to which he is well suited - no more than a third of those he actually sings - he can be splendid. Last season in ''Les Contes d'Hoffmann,'' he was ideal. Once again in ''Don Carlo,'' he proved masterly. It was not just a question of vocal weight and timbre, which suit the role handsomely. Rather, it was Domingo the actor who rose to the occasion.
Gone was the usual all-purpose romantic-hero posing that's used for most of his portrayals. In its place, he offered a richly detailed characterization that captured in minutest fashion the complexities and weaknesses of Verdi's most unusual hero - arguably one of opera's most auspicious antiheros.
Carlo cannot make right decisions. Every path he takes leads him to disaster. Domingo prepared us each step of this character's tortuous way. He was also in good voice, so that all the dramatic moments were matched vocally in what must be one of his finest performances ever at the Met.
Around him was a fine cast. Grace Bumbry sang Eboli, the role of her Met debut in 1965. She still retains the voice and the star presence that have set her apart, and it was a blazing account of the role she offered here. Nicolai Ghiaurov has deepened his interpretation of the role of King Philip since this production was new. The voice may be thinner and grittier than it used to be, but he made his points with skill and power. Louis Quilico gave his usual sturdy , robust, somewhat detached performance as Posa. In the pivotal role of the Grand Inquisitor Ferruccio Furlanetto was vocally inadequate and histrionically less than required.
Mirella Freni, returning to the Met after nearly 15 years, sang Elisabetta, a role that used to be the province of Verdi dramatic sopranos. Miss Freni left the Met a Puccini lyric soprano. Since then, under the aegis of Herbert von Karajan, she has graduated to the heavier, so-called spinto roles, although the voice has remained firmly lyric. But unlike Renata Scotto or Katia Ricciarelli, she has not done much damage to her instrument. The quieter moments of the role she sang limpidly, meltingly. In the fuller moments she found the edge to ride the orchestra, though the basic sound lacked weight. She is the best Elisabetta the Met has had in this production, though far from ideal, were the old standards of operatic singing still in effect.
James Levine's conducting of this score has to be one of his finest achievements to date. The overall vision is unfailingly grand, the attention to detail thrilling, and his ability to give his singers all the room they need to make their points, expert. The orchestra has rarely sounded so full, so symphonic, and so alert.
The John Dexter production still has serious problems: So many moments are staged in opposition to Verdi's instructions or in ignorance of them. David Reppa has put handsome gold facing on his butcher-block towers that form the core of the sets. The improvement is immeasurable. Ray Diffen's costumes remain handsome.