Last night's production of The White Devil at the Loeb went a long way toward vindicating the choice of Webster's complicated and allusive masterpiece. For the first time a group of actors concentrated seriously enough on clarity to prove that the theater's acoustics are not defective; and a director seemed aware that the drama center did not exist solely for the University's English majors.

All too often Elizabethan works are staged in a spirit of resignation, as if their plots are so remote or meandering that it is futile to emphasize anything but "the poetry." (Most directors who do realize that dramatic poetry cannot exist without drama, go to the other extreme and delineate plot-line until nothing is left of the text but a Hymarx outline.) The current production strikes a fitting balance: Webster's language is respected while his tale of murder and intrigue is played to the hilt.

The play's subtitle, Vittoria Corombona, might have been more apt than White Devil for the Loeb offering. The show was a vehicle for Jean Weston's Vittoria, and she rode it majestically. Her fury was never shouted, but came through instead as the disciplined, brittle, half-smiling anger of a real devil. Peter Haskell, though, prevented her from stealing the show. His unconventional Flamineo, more a pimp than a conspirator, lightened Webster's heavy psychologizing. As a commentator he clarified the story; as a murderer, he mad the killer's impulse seem explicable; and even when the action reached its bloodiest, he sustained its dramatic plausibility.

So exceptional were the performances of Weston and Haskell that it would be almost unfair to criticize the cast for failing to meet their standards. Almost without exception the play's acting is strong; only Arthur Friedman's Bracciano is repetitious and stuffy. Edward Landreth sounds like he's gargling when he's most enraged, but his expressive face and hands, plus a number of effective speeches enrich the play.

Webster found evil more dramatically attractive than good, and his sympathetic characters are hard to play. But Beatrice Paipert (Vittoria's mother) and Bruce Heck (Francisco de Medici) speed those scenes when neither Weston nor Haskell are on stage, expressing their lines and feelings with such specificity that one doesn't long for the protagonists' re-entrance. Tom Griffin draws Marcello's decency well, another bright contrast to the diabolical setting.

Chapman directed the play for its events, and never let the unfolding of his characters obscure or delay the story itself. His craftsmanship in designing the luminescent dumb show in which two characters are done away with illustrates this concern for action as such.

When Vittoria and Flamineo are on stage, you hope that Webster will forget how to write an exit line. Particularly in their syncopated death scene, murder is shown to be a business which impoverishes all its entrepreneurs.

Other aspects of the production left more to be desired than the acting. Donald Soule's set looked just a little bit uglier than the depressing Medieval court he intended to suggest; and Joseph Raposo's incidental music was indistinguishable from all the uninspired incidental music ever written. Make-up that was more lurid and costumes that hampered less would also have helped.

But such criticism is trivial. A polished cast enlivens a play that has already withstood the test of time. To begin its second season, the Loeb opens its doors with a bargain.