The "bridge" is a term I had heard before finding Rock Singing Success. I had been told there is one bridge, also called a passaggio and that learning to navigate the passaggio well (think of Chris Isaak singing Wicked Game) is the key to being able to sing with tonal consistency from low notes to high notes and not have your voice crack while you're doing it.
By tonal consistency, I just mean being able to sing throughout your range and not sound like one person in mode one and sound like somebody else in mode 2. Navigating the passagio meant being able to transition from mode one to mode two seamlessly.
That may be valid information. I learned it even before I ever met my first vocal coach, so since it didn't come from him, its certainly possible that it's an accurate description of what the "bridge" is: The thing that you use to move back and forth between modes one and two and not have your voice crack, or sound like two different singers.
As far as I know, unless you want to count fry as "mode zero", there are just two modes. Mode one is what you typically use to speak, unless you're Mickey Mouse, and then there's mode two, which is also sometimes called head register.
The voice breaks if you're not skilled in navigating the passaggio. I had gathered that you could think of the passaggio as the "bridge" that takes you from mode one into mode two.
This was my understanding of "bridge" before I found RSS.
R.S. found RSS. Imagine that! Good thing too, since the way I was being taught to create grit was pulverizing my larynx. "Just imagine you're lifting something heavy" - No thanks! If I were deliberately setting out to create as much unnecessary muscle tension as possible, then that would have been useful, but otherwise, no.
There had to be a better way.
"Just use the least amount of constriction necessary." - OK, I'm paraphrasing, but essentially that was what made RSS different from the way I was previously taught to create grit.
My first coach encouraged me to constrict until no air at all was coming out and then just release tension ever so slightly until a little air can finally escape and we have "Grrrrrit"! And Reinke's Edema too!
I don't care how many subscribers he might have. My first coach was "the bridge" leading my vocal cords straight into the lungs of hell.
Successfully surviving that first "teacher" and having bridged into RSS, now I'm learning things that are actually beginning to work!
RSS is a very different approach to teaching singing than I had initially found. in RSS, things are explained in logical, reasonable, non-contradictory ways.
Non-contradictory is good. Aristotle said: "..the same attribute cannot at the same time belong and not belong to the same subject and in the same respect."
In other words, contradictions don't exist in reality. A = A. That's the Law of Identity.
If you encounter a contradiction, check your premises. You'll find at least one of them will be wrong.
For example: "He's very well known on a certain social media platform, so he must be excellent at teaching people how to sing."
That he's very well known may be that he's an excellent self-promoter. I've never said he has no skills at all. He's persuasive. He could sell a nun a jock strap and make her think she got a good deal!
The ability to teach people how to sing in a safe manner is not correlated to social media popularity.
Never base your estimation of someone's ability to teach on how many subscribers they have. It would be like deciding you want to become a great chef and choosing to learn to cook at McDonald's because they've served more people than anyone else!
I navigated my way through the minefield of vocal coaches that is YouTube, I crossed that bridge and I found RSS. I've learned a lot in a short time.
I still have more to learn, For example, according to how things are explained in RSS, there are actually two vocal bridges. My first instinct was to say that can't be because there is mode one and mode two and a bridge or passaggio between them that you navigate to sing with tonal consistency and without your voice cracking. So, where would the second bridge go?
I'm not sure where it would go, but one of the nice things about this place is that you can ask and find out.