To sing well, we must learn to move from chest voice into head voice and be able to dance back and forth without difficulty. To be even more precise, we must learn to transition across multiple passagio/bridges, and to tonally match the bottom to the top and vice versa.
Although there is a particular pathway to achieve this, the exact nuances of the bridging process as felt by each singer can be a little different. And even within those nuanced routes, there are different strategies that are employable by even the same singer to colour the sound in different ways, whilst still being within the realm of technically correct and aesthetically beautiful singing.
Three examples of the same song by three different singers.
Pavarotti
If you listen to the opening notes, you’ll hear an overly narrow and tightly controlled vowel width (at his first bridge). This yields a rounder tone with great bottom end extension (as well as upper harmonics and ring).
If you listen to the climaxes later in the piece, you’ll hear a much wider approach to the next portion of his voice (second bridge). The tone still ‘matches’ the bottom, but there’s less of the same polished rounded bottom end and a gradually wider vowel than employed at his first bridge. The sound becomes more midrange focused and slightly more mouthy at his second bridge than his first. Still a beautiful sound (the whole world broadly agrees on this!), but Pavarotti employed a slightly different approach to bridging at his second bridge than his first.
Domingo
If you listen to the opening notes (again, around first bridge), you’ll hear a deeper tone overall (such was Domingo’s tone), and a narrow and tightly controlled vowel sound like Pavarotti’s approach. I personally hear a little bit of extra width in the vowels compared to Pavarotti (excluding the odd wider vowel Pavarotti throws in lower end) but still very tightly controlled.
However the key difference is at the climaxes later on. You should notice there’s very little difference in vowel width or tonal similarity at his second bridge when compared to his first. It’s a very very controlled and even sound from top to bottom. Both his tone and Pavarotti’s tone are self consistent, but I would argue there is even more consistency in Domingo’s sound than Pavarotti’s. This shows how similar his approach to bridging at his second is to his first.
Kaufmann
I present this as another example of another singer with yet a different tonality. His approach involves a slightly lower larynx (in my opinion) than the previous two singers, leading to a darker and thicker timbre overall. I’d say his vowel width is similar to Domingo, maybe slightly narrower at points, but the darker timbre can make it seem narrower than it is. You can hear a great deal of consistency in his approaches to his first and second bridges, though he’s somewhere between Pavarotti and Domingo in consistency in his approaches, at least in this piece.
Summary
Once you CAN bridge, you can (and inevitably will) shape and shade the exact nuances of HOW you do so and how you sound. This is in part determined by the physical preference of how it feels, and in part determined by stylistic/aesthetic preference of how it sounds.
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