You may have heard about vocal-cord adduction and the need to develop good cord closure. I won't address those topics here, but it is essential that the vocal cords stay together as a singer crosses the bridges. I will address instead the process of crossing bridges and the resonating effects of this, and I'll tell you about a few ways to trick your voice into these areas.
As the pitch ascends, sound traveling from the vocal cords shift paths. Chest voice travels to the hard palate and out of the mouth. As the pitch rises and goes over the first bridge, the sound begins to split, going behind the soft palate as well as to the hard palate. This is a balancing act of sorts. If too much sound is traveling in front of the soft palate and out of the mouth, the result will be a wide vowel and what is called pulled chest. A residual result will be a high larynx.
The right balance depends on which
note within the mix is being sung. By the time you're completely
in head voice, much of the sound will be traveling behind the
soft palate before exiting the skull.
Each time a singer reaches a bridge, more sound must pass behind the soft palate and more resonationation within the skull should take place. Singers resist letting sound pass behind the soft palate for a couple of reasons: The first is that they hear the tone bouncing within the skull and feel that it sounds too ringy. They don't realize that the sound they're hearing is not what the audience is hearing. They're picking up this sound through the skull, not from within the room they're singing in. One way to deal with this is to record yourself passing into mix and head voice; then play back what you've recorded. You will hear the difference between how you really sounded and the sound you heard resonating in your head.