When the Metropolitan Opera unveiled its new production of Francis Poulenc's ''Dialogues des Carmelites'' (''Dialogues of the Carmelites'') on a nationwide radio broadcast performance in 1977, it was instantly evident that Poulenc's unusual music drama continued to enthrall and engross 20 years after its world premiere in La Scala, Milan, Italy. It has kept its hold on the Met repertoire, and the current revival will be the first live broadcast of the Met's centennial season (airing tomorrow in many areas).
The only recording of Poulenc's opera ''Dialogues des Carmelites'' was issued back in 1958 and still remains in the catalog. It is a studio performance featuring the entire cast from the Paris Opera premiere in 1957. (The world premiere performance was at La Scala early in '57, in Italian!) The sound is mono, but the array of talent, from Regine Crespin through Denise Duval (Poulenc's favorite singer) to Rita Gorr and Denise Scharlay, is spectacular. Under the baton of Pierre Dervaux, the sense of re-creation of a unique performance is everywhere evident.
Verdi's ''Ernani'' - to be heard on radio live from the Met the week following ''Dialogues'' (Dec. 17) - has not fared especially well on records. An old Cetra set used to kick around on Everest, and in 1968 RCA released a snappy but compromised set featuring Leontyne Price, Carlo Bergonzi, Mario Sereni, and Ezio Flagello. The late Thomas Schippers conducted this impetuous melodrama with fire and passion.
Miss Price and Mr. Bergonzi proved everywhere committed and fiery themselves - even if Miss Price was not in her top form for the sessions. However, Messrs. Sereni and Flagello were the telling weak links in the cast. So one must make do with this recording.
A recent issue on the Hungaraton label features an all-Hungarian cast, Lamberto Gardelli conducting. There is always the chance that Luciano Pavarotti, who sings the role in the new Met production being broadcast this year, will want to record it. If that is the case, then there is the hope that he will be surrounded with as good a cast as Miss Price and Mr. Bergonzi deserved in '68.
These programs are broadcast over the Texaco-Metropolitan Opera Radio Network (check local listings).