As the cast of South Pacific moves toward critics' performances (this weekend) and opening night (next Thursday), I find myself thinking again and again about the show's orchestra, and, in particular, about its harp. That instrument, and its player -- whose name is almost too apt for such an archetypally celestial sound: Grace Paradise -- do not, as with most orchestras, sit on the near-sidelines of the ensemble. Here they have pride of place: smack in the center of the 30-member band.

I asked the show's musical director, Ted Sperling, to explain the harp's placement. "There's no piano in this orchestra, and the harp takes on some of those duties -- helping to keep time, for example." He went on: "The sound of the show should be pretty lush, and the harp helps adds that lushness." The orchestrations, however, steer fairly clear of that crushing harp cliché: the glissando. "Robert Russell Bennett thought glissandos were kitschy," Sperling mentions.

Bennett, of course, did the show's original orchestrations. (Trude Rittmann did dance and incidental music arrangements.) "We were all excited at the thought of using Bennett's work," says Sperling, who himself won a 2005 Tony award for orchestrating (with Adam Guettel and Bruce Coughlin) the LCT production of The Light in the Piazza, and who was recently named director of the Public Theater's Musical Theater Initiative. "But," Sperling continued, "we did wonder if those orchestrations would hem us in, since orchestrations, at least originally, are designed with specific productions in mind."

Sperling says the orchestrations have worked out well. "The Rodgers & Hammerstein Organization wanted us to honor the show's original creative work, but they also wanted something fresh and revealing. I think you can see that spirit at work in the orchestrations we use every night." Sperling mentions that if he's ever in doubt about something in the score he can consult the scholarly new edition of the orchestrations that the R & H Organization did for the LCT staging. "I can also take a look at the actual pit parts from the 1949 production. I keep them in my dressing room."

Brendan Lemon is the New York theater critic for the Financial Times.