PARK YOUR CAR IN HARVARD YARDComedy by Israel Horovitz. Directed by Zoe Caldwell. Starring Jason Robards, Judith Ivey. At the Music Box. MUSIC is the food of love, or at least of affection, in the companionable new play at the Music Box. Israel Horovitz's "Park Your Car in Harvard Yard" is a poignantly comic verbal duet. Jason Robards and Judith Ivey play it with finesse. The comedy begins with the arrival of Kathleen Hogan (Ms. Ivey) to be live-in housekeeper for Jacob Brackish (Mr. Robards), long-retired teacher of high school English and music appreciation in the Gloucester (Mass.) school system. The recently widowed Kathleen was married to a short-order cook who was "not one for long sentences." Jacob, on the other hand, is a voluble academic with a knack for a variation on a familiar quote. ("To err is human. To forget is divine.") At their initial encounter, Kathleen tells her new employer that this is the first time she has ever had a room of her own. The reclusive Jacob confides ruefully that, notwithstanding his years of teaching, none of his former students has ever visited him. The cause of the isolation and - as the playwright ultimately reveals - its connection with Kathleen's own personal and family history go to the heart of this study of related lives that have never directly touched. In the course of the delving, the playwright reveals the intellectual elitism that has separated Jacob from his plebian pupils. For her part, Kathleen looks back on a suddenly ended school career, concluding that her problem was "the grades. I didn't fail. I was failed." It is Mr. Horovitz's intention to resolve the impasse between these intellectual opposites. The resolving element is the music - the Bach, Beethoven, Brahms, and the Pachelbel - that Kathleen comes to know and appreciate through Jacob's vast recordings library. As the story unfolds, revelations of significant past relationships begin to surface. "Park Your Car in Harvard Yard" is a play of small but pertinent details - from the intrusions of the creaky-voiced announcer on the Gloucester radio station to Jacob's introduction of his tiger cat. The excellent performance staged by Zoe Caldwell responds to details large and small. A bearded Robards carefully and gradually traces the crusty intellectual's progress from Jacob's initial air of unquestioning self-satisfaction to the realization that his insistence on academic standards may have had an unthinkingly harsh side. In Ivey's sensitive portrayal, Kathleen overcomes longstanding hurts as she achieves the compassion that provides the final grace note of this tenderly written play. Ivey also assumes an authentic-sounding Yankee accent for the character. Ben Edwards' multilevel setting provides an appropriate environment of comfortable shabbiness for Horovitz's appealing genre play. The picturesque production was costumed by Jane Greenwood and lighted by Thomas R. Skelton. "Park Your Car in Harvard Yard" runs an hour and 45 minutes without intermission.