Chest Voice

I think everyone would agree the goal is to have an integrated seamless blend of registers from bottom to top. I would argue that all women mix chest voice in varying degrees in all parts of the voice, on the bottom it is mostly chest, and on the top mostly head, and dramatic sopranos carry some degree of chest all the way up to the high C. Nowadays it would be unthinkable however to use chest voice in a way that caused a distinct break in the voice. I have heard crossover singers use a sort of Broadway belt in the lower registers, to my ears it sounds absolutely horrible.

Kraus on Covering

I understand that Alfredo Kraus was perhaps a bit rebellious, a bit individualistic, and very proud of his own technique and vocal accomplishments. Nevertheless, he did cover and he did have a passaggio like every other tenor. He is correct in saying, as you quote him, that breath support is the fundamental issue of vocal technique. Having excellent support removes or solves various vocal problems and issues. It is Kraus's strong breath support that made it seem easy for him to sing passaggio notes and build and retain his wonderful top register. He admits that the passaggio marks a different register. It is this register change that requires reinforced breath support and covering. I suspect that Kraus either had forgotten the terminology he learned during his vocal training or was quixotically denying it. Certainly a singer can employ correct technique, as Kraus did, without accepting the usual terminology to describe it. Many fine singers learn good technique but are unable to intelligibly communicate it to students. You (Stefan) acknowledge that covering was gospel for many singers, including Corelli and Bergonzi. Corelli told you, I believe, that he could not imagine singing without covering. So let us merely agree that Kraus chose not to apply that term to his own singing.