HERBERT: "SOUVENIR" AND "L'ENCORE." Arabesque 6529 and 6547. ROMBERG: "WHEN I GROW TOO OLD TO DREAM." Arabesque 6540. Teresa Ringholz, soprano. Donald Hunsberger conducting the Eastman-Dryden Orchestra. This is the kind of music many dismiss as lightweight. Though it may offer few surprises, it is always pleasant and often charming. Hunsberger obviously enjoys this music and his student orchestra follows the authentic arrangements with precision. The first Herbert album features the ambitious "Cuban Serenade," written in 1924 for the Paul Whiteman concert overwhelmed by Gershwin's "Rhapsody in Blue." Excerpts from three operettas are sung by Ringholz with that now-lost combination of innocence and sauciness. The second Herbert volume contains selections from "The Red Mill," "Sweethearts" and "Babes in Toyland." The Romberg CD features 53 minutes of music from "The New Moon," "Maytime," "Desert Song" and "Her Soldier Boy." It is lovely stuff grabbed out of another time and place in pristine condition.