Indeed great. Author' operatic thinking is the best part of his approach to the poetry!
I enjoyed tremendously!
The only mention: Alboni whole being transformed in specific characteristics of her voice should be not associated with Marilyn Horne.
Probably,the closest sound had Jeanne Gerville-Reache, judging on a few of her recordings(cantabile-subito.de). It's difficult to find a modern replica of Alboni' voice, as the modern vocal production just way too far from Alboni'era.
American voice production is just too far forward;Horne'voice specifically is a soprano,but not a dramatic one,that often might be treated as a contralto,Marilyn' voice is a lyric soprano with artificially developed low extension. It does not diminish her art at all though.
Most certainly Alboni was a soprano (according to Blanche Marchesi, Alboni' pivot notes F-G suggesting it ). Incredible and interesting documentary. Forgive my English please.