A very interesting post, Andrew -- and I'm impressed that, like Lanza
in 1958, Florez was able to fill the vast Albert Hall auditorium
without a mike!
Yes, I've also noticed that lower voices tend not to project as well
as higher voices. As for squillo, you're right that Lanza had this "in
spades"! This has often been commented on those who were lucky enough
to have heard him in person. There's a very good description of
Lanza's squillo by one Merlyn C. Minick, who in 2000 recalled the
experience of attending Lanza's 1951 Kansas City recital:
"What I remember and admire most about Lanza's voice was its lyric
versatility and the voluminous and exquisitely clear and breathtaking
"ring" (bell-like) to his high notes as well as the soothing and
mature mellowness to his lower register. The so-called "ring" to
Mario's voice was particularly captivating and his ability to catapult
(if you will) the sheer brilliance of his voice to the far reaches of
any auditorium was uncanny. While listening to him (in the flesh), I
certainly relished the warm sound as it was being produced but I was
always more enraptured by his high notes and the residual or
"lingering" of his sounds which seemed to stand still (in time) as
they permeated the expanses of an auditorium, after sound production
itself had ceased. This lingering effect was not a result of "echoing"
per se but was in effect a suspension of the long-lived or lingering
reverberations which muscially described the "bigness" of his voice,
even as it was subsiding. This lingering effect was noticeable while
singing in the lower register but was particularly appealing and
brightest while Mario was singing in his highest register - - hence
that "ringing" sound. His stunningly beautiful and powerful high B, at
the close of La Donna E Mobile, literally shook the walls of the
auritorium. His top notes always ended having this reverberating and
lingering property [...]."
(From an essay at
http://www.rense.com/excursions/lanza/listen.html)