The most important questions about the New York City Opera's "La Traviata" were answered early last evening at Wolf Trap.

One can't really vouch for the soprano and tenor leads in tomorrow night's repeat performance; they will be changed from the cast that last night opened the company's week at Wolf Trap. But in its underlying, permanent aspects, this production gives full satisfaction. These aspects include the conducting of Michael Morgan, the stage direction of Frank Corsaro and the expert supporting cast, notably Pablo Elvira in the role of the elder Germont.

In the principal roles, if Marilyn Mims and John Stewart tomorrow come anywhere near matching Leigh Munro and Jon Garrison last night, it will be a "Traviata" well worth seeing and remembering. The singers were well chosen to portray young, attractive people, visually as well as vocally, and both sang excellently, allowing for one or two pinched, forced or unfocused notes.

Morgan is already familiar to many Washington opera fans through the noteworthy "Traviata" he conducted for the Summer Opera Theatre a few seasons ago. In this performance, as in that one, he proclaimed a distinctive but not eccentric musical personality from his first downbeat.

He maintained a delicate balance throughout between the voices and the transparent but flavorful orchestral sound, and his balancing act became almost a virtuoso display during the soprano-orchestral swells of "Amami, Alfredo," where the orchestra remained always a cushion for the voice no matter how frenzied the dynamics became.

Morgan also likes to play with the beat and, sometimes, to slow the tempo right to (but not past) the brink of self-indulgence. He does it, however, always with a clear awareness of what he is doing and why. He looked like a major talent when he was conducting in Washington, and he still does now that he has shifted his energies to Chicago and New York.

Corsaro has done some fairly radical stage directing for this company (last season's 20th-century, politicized "Carmen," for example), but this "Traviata" is a loving, straightforward treatment, notable for an occasional ironic touch but mostly content to wallow unabashedly in romantic sentiment. Like Morgan's musical direction, Corsaro's staging maintains a constantly focused energy in the performance.

No opera has a stronger audience appeal than Giuseppe Verdi's tear-jerker about the courtesan Violetta, who dies of tuberculosis after discovering and renouncing true love. Opening a season with "Traviata" is about as cautious as an opera company's programming can get, and such caution is not typical of the New York City Opera.

This relatively small and low-budget company has often managed to shine, even in the shadow of the giant Metropolitan Opera next door in Lincoln Center, by the daring and imagination of its productions. Its choice of a Washington season devoted entirely to operatic Top 40 ("Tosca" and "The Student Prince" besides "Traviata") may reflect an opinion of Washington audiences or simply the necessity of selling a lot of tickets to fill the vast spaces of Wolf Trap.

If the choice of repertoire was a bid for a mass audience, it worked imperfectly on opening night, though the opera could hardly have been more popular or the performance much better. The reserved seats were fairly well filled, but attendance on the lawns was barely half of what it might have been -- a pity because this is a good show when viewed from most lawn locations. The visuals work well even at a fairly long distance, though this is the most intimate of Verdi's operas, and the sound system seemed clear, undistorted and well balanced.

It may be that the surtitles, which are doing so much to enlarge the opera audience, are cutting down the lawn attendance. They cannot be seen from the lawn except at the very front, and their importance to a large segment of the audience grows steadily clearer.

For a moment during "Ah, fors' e lui," the titles were flashed not on the screen but on the wall of Violetta's ballroom, and the audience's disorientation could be felt. Later, during "De' miei bollenti spiriti," a sentence was flashed on the screen upside down and the instant, universal laughter showed how closely the projected words were being followed.

The translations sometimes honored the spirit of the text more than the letter, and they did not (as Frank Rizzo's for the Washington Opera consciously do) echo the rhythms of the Italian original. But their lucidity, like the clarity and focus of the conducting and stage direction, make a significant difference in the effect of this production.