AN AUDIENCE hoping to extract some enjoyment out of The Rep Inc.'s season opener, "Modern Time Blues," will have to invest more effort than is apparent on the part of the theater company. Director Jaye Stewart has put together a topheavy double-header of one-act plays: Leonard Melfi's salvageable slice-of-life "Birdbath" hits home occasionally; pulp novelist John Jakes' irredeemably silly sci-fi "Stranger With Roses" misses badly on all counts.

Melfi's "Birdbath" is an odd, downbeat vignette about an unsuccessful one-night encounter between two lonely urbanites -- a broom- pusher who fancies himself a poet and a neurotic waitress who attaches herself to him in last-ditch desperation.

To show that alienation is one of the sad costs of city living, Melfi has formed two realistic but unsavory characters, unfortunately overplayed by The Rep's cast. Billie Taylor's hysterical, pathetic Velma Sparrow, a walking inferiority complex, is literally breathtaking -- the actress acts all over the place, gasping and trembling so that the audience collectively draws breath for her. Taylor is certainly affecting and irritating in the way the playwright seems to intend, but for the audience, her nervewracking performance is physically hard to endure. As Frankie, L.M. Dyson fares better, his surface composure peeling slowly away when exposed to Velma's nerves and a few ready-made martinis.

"Stranger," Jakes' play, sounds as if it were knocked off in one night, without rewrites, between novels. Set in a West Coast megalopolis in post-apocalypse 2003, Jakes' skimpy effort is a faint attempt at a morality play tacked onto a transparent "mystery" about a stranger who may have traveled from the pre-war past. Most viewers will have this one figured out by the close of scene two.

Nuclear war or no, the future will never look as bad as this. Arguments about budgetary restrictions aside, The Rep's costumes and sets would be laughable if they weren't so crude. And the five-member cast is weak, with the exception of the elaborately made-up Jewell Robinson, who adds some life and (perhaps unintentional) humor by playing the whole thing with the oversized reactions of a silent screen queen. MODERN TIME BLUES -- The Rep Inc. At GALA Hispanic Theater through January 26.