I’ll bet you thought this would somehow involve 3 elves and a bowl of cereal but it won’t. It is about the sound that a cracking voice makes when you address an audience. That sound quickly goes away but it still leaves the audience with the impression that the speaker is uncomfortable, maybe even fearful of public speaking. The speaker is aware that their voice has cracked and that awareness can disrupt their chain of thought. A bumpy start can affect the entire presentation.
Since you want to make a positive impression on the audience and to exude professionalism, you want to eliminate that cracking sound when you speak. Practicing a very simple exercise just before you begin to speak can do that.
The trick is to acclimatize your vocal cords to the air temp in the room before speaking. That cracking is caused because the speaker takes an initial deep breath immediately before they speak. That is a natural thing to do because the speaker wants to speak loud enough so the people at the back of the room can hear. You try to speak louder and you take a deep breath to prepare for that.
What you do in the minute or so immediately before you speak can completely eliminate the cracking voice problem. Some people do this automatically but others have to consciously make an effort to do it. If you are in the second group, make a mental note of this and remember to do it and you won’t have a problem with a cracking voice.
The exercise is simple and effective. It will work without fail as long as you remember to do it. So what is this magic exercise for speakers? The exercise is to breathe through your mouth deeply several times before you speak. A nice rule of thumb is to start this exercise when you are being introduced. It only takes 2-3 good, deep breaths.
Of course, all possible benefit is wiped out
If you hyperventilate, turn blue and pass out.