Saturday's Metropolitan Opera performance of "The Magic Flute" st Wolf Trap would have been just another Mozart matinee if 29-year-old Carmen Balthrop hadn't been on stage.

A native of Washington, Balthrop won first place in the Met's 1975 auditions and was making her Washington debut with the Met in the role of Pamina - daughter of the almost metaphysical Queen of the Night - which as roles go is not the greatest thing to try to act out on stage.

Well, Balthrop certainly looks good on stage, but it was virtually impossible to understand what she was singing. As it was in her performances with both the Atlanta and Houston stagings of Scott Joplin's "Treemonisha" (where she began getting national attention), Balthrop's words seem to jumble together into a rather undifferentiated mass. Her voice sounds nice, but you have no idea what's being said.

This may not have been completely Balthrop's fault. The Met chose to sing the opera in English, and the already quirky, somewhat arcane libretto consequently took on all the joy and lightness of a stodgy simultaneous translation of some forgotten Latin tome. Balthrop wasn't the only one who couldn't be understood; most of the lines were indecipherable, with the exception of Tamino's and Papageno's, sung respectively by Jon Garrison and Donald Gramm.

Much has been written about the impossibility of staging a first-rate "Magic Flute." Indeed, its magic forest setting and underpinnings of Freemasonry make it at best a compromise to put on. Marc Chagall's settings and costumes, for instance, lose their magic after 20 minutes, and it's difficult to accept a scene like the dragon-slaying that opens the opera.

Somehow Ingmar Bergman's 1975 film of "The Magic Flute" still seems the best rendition of the opera as a theater piece, even as performed by a not-well-known Swedish company and sung in a Swedish translation from the original German.Bergman used the medium of film to create the kind of magical illusion that probably could be put on stage but has never been.

But these perhaps are trifles. The opera's music, written in Mozart's dying days, is always a sweet, breezy treat, particularly when it is a well-paced and phrased as by 26-year-old conductor James Conlon. Now there's a guy to watch.