In a 1979 interview Moross remarked that he was at work on a second symphony, and a quantity of extant sketches attest to this. However, his last compositions are for chamber works. Moross’s last two works are scored for string quartets: Sonata for Piano Duet and String Quartet (1975) and Concerto for Flute with String Quartet (1978). Moross was excited about his final instrumental works, sensing that audiences would appreciate his new sound. As he described his music, “It uses classical grammar and makes modern music with it. . . . It writes music that an audience will like, will listen to; not because I want to just coddle the audience, but because that’s the way I feel.”[xxiii] Indeed, this was an approach that Moross adhered to throughout his entire career, music that utilizes traditional modes and infuses them with popular American idioms.
Moross returned to dramatic composition once more, composing a single one-act opera, Sorry, Wrong Number (1977), based on the radio play (1943) and later film (1948) by Lucille Fletcher, the former wife of Bernard Herrmann. Moross once commented that it had always been his intent to “change the theatre” to make it operatic, and he cited The Golden Apple as the premiere example. Acknowledging that his attempt may have been unsuccessful, and that “The theatre doesn’t want me. . . .” Moross decided to move into “pure opera.” With Sorry, Wrong Number Moross ventured into unfamiliar territory by setting prose to music for the first time. As he later noted, “[Fletcher’s] prose is beautifully done and it allowed me to even get ariettas throughout the thing. I trained myself for the first time to write to prose, and now I’m no longer afraid of trying to get a play and turning it into an opera.”[xxiv] First premiered in 1977, it was performed again in 1980 and 1982.