Truly Grand Opera. With revenues up, the Opera Company of Boston exudes confidence in its dramatic, musically rich staging of `Aida'. MUSIC: REVIEW

THE Opera Company of Boston's ``Aida'' is grand opera - a production replete with superb cast, a dazzling array of costumes and colors, and plenty of pomp. But it is more, too. It shows off the fathomless musical imagination of the company's artistic director, Sarah Caldwell, at her very best, plumbing the depths of Verdi's characters and pushing relentlessly home the vivid, joyfully human but ultimately tragic story of love between Radames, a warrior of ancient Egypt, and the slave Aida.

Shirley Verrett, who sang her first Aida for Miss Caldwell in 1980, now brings a softer, more inward-looking approach to the part. Her voice on opening night last week was honeyed, subtly colored and, in its unostentatious honesty, deeply moving.

Markella Hatziano as Amneris, the princess who is determined to possess Radames, is quite Verrett's equal. She projects jealousy with an intensity that rivals, but cannot extinguish, the purity and innocence of Verrett's Aida. Franco Bonanome sings an effectively heroic (rather than bel canto) Radames. And David Arnold is persuasive as Amonasro.

As followers of Caldwell know, however, her dramas are not confined to the stage. A year ago, the company's new president, Robert Cannon, took over the business side of an organization which, in his words, was ``in disarray from a management standpoint.'' A growing debt - now at approximately $5.5 million, according to Mr. Cannon - continues to haunt the company. But management is more stable, he says.

New board members were brought in, many from the business community, and tough decisions were made. Only one new production - Leonard Bernstein's ``Mass: A Theater Piece for Singers, Players, and Dancers'' - was allowed for the current season. The three other productions are revivals. And the number of performances for each production has been reduced from four to three.

It was also decided to have a ``much more popular program ... to help us increase attendance and revenues,'' explains Cannon. ``There is a certain amount of compromising there, although from an artistic standpoint we feel that this season is much better organized.''

The marketing effort was reorganized, as well, and the subscription drive began earlier than in the past. ``Our revenues this year are up some 40 percent over last season,'' says Cannon.

Maybe that's why this ``Aida'' exudes such confidence.

The interraction between Hatziano and Verrett in the first scene of Act II, for example, is remarkable. Miss Hatziano's venom is coated with the thinnest layer of sugar, as she uses cruel deception to unmask Aida's love for Radames. The coating vanishes entirely when she tells Aida that Radames is dead, her voice dropping darkly to sharpen the word morte. For the rest of the scene, Amneris's hatred and vanity are left unsheathed, while Verrett - making Aida's torment palpable - sings with a ravishing beauty.

Hatziano's tone changes for the final act. As Amneris pleads with Radames to defend himself against accusations of treachery, she becomes vulnerable. With the trial of Radames taking place off stage, and the chorus of priests blood-curdlingly repeating ``Traditor!'' (traitor), she looks very much alone.

Mr. Bonanome, a student (like Hatziano) of Tito Gobbi, projects boldly, and his ``Celeste Aida'' is crustily passionate. At times, some of his gestures are a trifle stiff, but his breathless horror is more than apparent as Radames realizes he has betrayed his country.

David Arnold is especially dramatic in his confrontation with Aida. But of the male singers, none has a greater command than Armenian-born Barseg Tumanyan in the role of the high priest Ramphis. Mr. Tumanyan's singing is as precise as it is dark. His is the voice of fate.

Under Caldwell's baton, the orchestra is as much an actor as any of the singers. Her strings play tautly to establish tension but with a smooth expansiveness when pathos is called for. The woodwinds add a special piquancy to the more personal moments.

The action is, for the most part, crisply managed on the attractive sets, designed by Herbert Senn and Helen Pond. The chorus is placed at the sides of the Opera House stage, with the men to the left, the women to the right; the interplay of their voices makes for a thrilling effect. The orchestral sound is especially vivid, with trumpet blasts emanating first from one side of the stage, then moving to the other.

``Aida'' has its last performance Sunday at 3 p.m. The season continues with ``Der Rosenkavalier'' April 13, 16, and 23 and ``La Boh`eme'' June 1, 4, and 11.

Clouding the company's horizon at this writing, however, is a proposal by the Massachusetts House Ways and Means Committee to eliminate Massachusetts Arts Council funding from the state's budget next year. Currently Arts Council money provides about 10 percent of the company's operating expenses, and its loss would be ``devastating,'' according to Cannon.

Opera lovers here in Boston hope that doesn't happen. With the rare genius of Caldwell at last supported by responsible management, it would be a pity to jeopardize the future of this priceless company once again.