A Smashing `Aida'. MUSIC: OPERA

VERDI'S ``Aida'' has been, for most of its history, the quintessence of grand opera. No major opera house can afford to be without a good production of the opera, for even a moderately well-cast ``Aida'' will sell out if the spectacle is suitably impressive. And yet ``Aida'' is the easiest opera to miscalculate. Too much setting swamps the piece; too little makes it seem silly. Too much directorial intrusion, or ``conceptualization'' can sacrifice Verdi's characterizations to metaphor or statement; too little means the opera lacks focus.

Oddly enough, this problem comes to mind in thinking about the Metropolitan Opera's fabulous new production of Verdi's Egyptian saga, which, to me, strikes the right balance between message and spectacle. Director Sonja Frisell's direction, Gianni Quaranta's sets and Dada Saligeri's costumes do not stint on the sheerly breathtaking panoply, but at the same time they allow room to present the individuals as individuals, with real histories and personal dramas.

What makes this a good production is what makes any opera production good: It tells the opera's story clearly; it frames the story handsomely; it gives the audiences a rousing good time. The director and designer have done their homework. They have paid attention to details. They have a good theatrical sense. They use the stage space most effectively. They give the singers enough ``room'' to contribute their own finishing touches to the director's ministrations/outline.

Throughout, there is the feeling of life unfolding in a monumental society, of people within and outside of a crushing social system, of heroes, fidelity, treason, and clerical fanaticism. The first act opens, not in the throne room, but outside the palace, where Radames nervously awaits his appointment as general of the Egyptian army. His drama - vying for public glory without sacrificing personal happiness - has rarely been more convincingly put forth. In fact, this staging fulfills its over-publicized promise as giving us both the public and private - spectacle and intimacy - of Verdi's carefully conceived opus.

The sets rightfully dwarf the performers. The Temple of Ptha is dominated by a statue to the god, of which we see only the lower legs; the ``Triumphal Scene'' is a major spectacle on some fantasy Theban avenue. Yet, apart from turning a few of the ballets into rituals - particularly in the temple, where the priestesses dress Radames in the sacred armor laid at the statue's feet - Frisell's only ``intrusion'' occurs in the final scene. As Aida and Radames suffocate in their tomb, the priestesses replace the armor on the altar, to await the induction of the next hero/general.

The Met now has an ``Aida'' of which it can be rightly proud. Ironically, it is the sort of production the critics are becoming militantly less fond of, however. One reviewer observed that using the Met's set-changing elevator had become an applause-mongering clich'e. Fortunately, the audiences don't give a fig. They applaud the sets lustily, and if this is the price one has to pay for the theatrical impact of those huge sets ascending or the Met's gold curtains parting to reveal something truly breathtaking, I'll pay it.

That said, the critical attitudes do put the companies on the horns of a potential dilemma: While critics do not necessarily fill opera houses with their raves (subscribers fill seats), to alienate them altogether creates an atmosphere of distrust that eventually rubs off on audiences in one way or another. So I can understand the frustrations the Met must feel when even this good a production is not received with the universal acclaim it deserves.

LEONA Mitchell has the sumptuous soprano for Aida, but she rarely used it to sufficiently skillful or commendable ends the night I heard her. Pl'acido Domingo was a very good Radames in all but the ``Nile Scene,'' where his high notes sounded strained. Sherrill Milnes used his imposing stature to great effect as Amonasro, and he sang much of the role imposingly.

There is nothing veteran mezzo soprano Fiorenza Cossotto doesn't know about the role of Amneris, and if the voice has lost its former plushness, her characterization is still so towering, one can almost overlook the decline in vocal allure. Paul Plishka was miscast as Ramfis, and artistic director James Levine led what, for him, must be called a routine performance.

So, as is often the case, the Met has unveiled a magnificent ``Aida'' in search of a cast, one that will look smashing on the inevitable TV telecast (whenever that occurs), and one that will hold the company in good stead for many a year to come.

During the holiday season the Met offered its enchanting Nathaniel Merrill/Robert O'Hearn staging of Humperdinck's ``Hansel und Gretel.'' The cast was not particularly good. Hearing Judith Blegen's Gretel or Hilda Harris's Hansel was difficult. The production has been neglected; the lighting is now so drab that many of the special effects are lost. Nevertheless, the opera still has magic, and this time around, under the baton of Christof Perick, the score was treated with the respect it deserves. On opening night the orchestra played the best ``Hansel'' I have heard at the house.