In opera, experience -- not youth -- can be the key

In opera as in the rest of the performing arts, there is simply no substitute for experience.

In an age when younger singers are being pushed far too quickly and damagingly, it is good to be able to hear experienced singers who have let neither poor repertoires nor timing dull their instruments, or who have managed, even with reduced vocal resources, to achieve an insight into performance that no youngster can communicate.

At the Metropolitan Opera in recent weeks, I have encountered Joan Sutherland , Alfredo Kraus, Carlo Bergonzi, Evelyn Lear, Lucine Amara, Gabriel Bacquier, Jerome Hines, and John Alexander. All of these singers are active at an age when many sit in their parlors poring over memorabilia. Yet they all offered performances of an insight, depth, and style that their younger counterparts are simply not - in most instances - getting across.

Miss Sutherland and Mr. Kraus were heard together in Donizetti's ''Lucia di Lammermoor'' (to be heard on live radio broadcast Dec. 4 - check local listings). He has become one of the most distinguished lyric tenors on the scene , lionized in Europe, Chicago, and, of late, at the Met (from which Miss Sutherland had been absent for four seasons). To have them back together is a special treat.

Miss Sutherland sings with all the agility and style one remembers, with the timbre and the range virtually intact, only a certain caution reminding us that it was more than 20 years ago that she exploded onto the New York opera scene with her electrifying Met debut in the same role. She maintains, in her way, the high standards set then, and to this day there has been no one who can sing this music in so large-scale, so glorious and virtuoso a fashion.

Mr. Kraus may lack the sheer power to register in the major outbursts of this opera, and the voice has always had a slightly dry timbre. But he is a fiercely imaginative singer. In quiet music, with tapered dynamics - pulling back from a mezzo-forte to a melting pianissimo - he has no equal. The poetry and ardor of his singing were ample proof that he remains one of the great lyric artists of the day. From the two of them, it was a superb evening of bel canto style. 'A Masked Ball'

When Mr. Bergonzi was heard in Verdi's ''Un Ballo in Maschera,'' it was unexpected: The entire scheduled cast had backed out before the first night of the revival. At times his work was touch and go when the upper reaches of the voice simply failed him. He has always known what a vocal line - in this case, grand Verdian - is all about and how to project it. More than occasionally he reminded us of the Met as it should be. Although he sang in a production of real ugliness, that will not be a factor on the radio broadcast next Feb. 19, when the tenor will be joined by Carol Neblett, Roberta Peters, and Leo Nucci - check local listings.

Miss Amara, another exemplary Verdi artist, proved in a recent ''La Forza del Destino'' what an asset she has been to the Met. Her voice sounds as fresh as ever, and her attention to words is even more acute than it used to be, and she remains the exemplary musician that she has been from the beginning. In these generally substandard Verdian times, Miss Amara's presence is doubly welcome both for her stylistic security and authenticity. 'The Barber of Seville'

In a sprightly revival of last year's new production of Rossini's ''Il Barbiere di Siviglia,'' Dale Duesing brought an ebullient, enchanting presence and an average baritone to the title role.

But it was the two basses, Mr. Hines and Mr. Bacquier, who brought genuine distinction to the evening. The former's Basilio was sung with great strength and resonance in the lower depths of his still vital instrument, and his characterization was exactly to the point. Mr. Bacquier has shifted from a fine baritone to a grand buffo artist. He plays each moment seriously and wisely, and always demonstrates that the best comedy comes from reality, not posturing. And the quality of the voice is still substantial. He is in every way a buffo master , as he proved here (and earlier in the season as Fra Melitone in ''Forza'').

Evelyn Lear has put her own stamp on the Marschallin around the world, including a run at the Met in 1974 and a recording of the role on Philips Records with Edo de Waart conducting. Her one performance at the Met (she will also be heard in the role on the company's spring tour) showed just exactly what experience is all about. The voice has darkened; the interpretation, compared with the recording, has deepened. Miss Lear shows off a multifaceted woman, clearly treading the fine line between the public and private person with grace, taste, and poise. 'Idomeneo'

Mr. Alexander's Arbace in the new production of Mozart's ''Idomeneo'' is imposing. The role is usually pared to nothing. At the Met, Alexander has his two large arias restored to him, and he executes them with the requisite dignity and a firm sense of Mozartean style. (The production will be seen Jan. 26 in the United States on PBS - check local listings.)