Why my old voice teacher’s technique sucks. This particular technique requires that you know exactly what note you are singing at all times (relative to the chromatic scale). The reason for this is: you have to know which vowel shape needs to be modified, relative to the note you are singing, that corresponds to your passaggio…and, apparently, you have 8 of them.
This voice teacher, coincidently, retired at 40 and sang Papageno over 100 times at the Metropolitan Opera, in the span of about ten years. Pardon my exasperation, but when I’m on stage, playing a mentally challenged homosexual bird-man, I’d like to be invested in what I’m saying and my motivations…namely, to bump uglies with Tamino and catch birds.