I haven’t spoken about Registers, which are a big bugaboo. There are lots of theories and research on the registers, but we can find out for ourselves what seems to be true:
There are two registers, which we call Chest and Head or Falsetto.
If you sing up from the bottom of the voice, there comes a point where you either have to stop, or shift over into something else. In women’s voices, this is the “normal” register for singing. In men’s voices, this is a kind of weak, female sounding place, which most men don’t use very much.
Simply, there are two sets of muscles involved with making sound. When one set dominates, you get a “register” or series of notes all belonging to that one mechanism. So what’s happening at that “break” point is a sudden shift from domination by one set of muscles to the other.
The problem arises in that we don’t usually have the same strength in both sets of muscles. Women usually have more developed strength in the head voice, men in the chest voice, because of the way we speak.
The solution to the register break problem is to develop the weaker register and then figure out how to join the two together by learning to “trade off” the domination in the middle part of the voice where the registers overlap.
This is a very tedious problem, and can usually only be successfully done with the help of someone who understands registers and how to deal with them.
Foreman, Edward. Transformative Voice. Pro Musica Press, 1998.