The Power of Breathing
Breathing plays a central key in singing. It dictates rythm and style. Try breathing quickly ang your sound (or style) changes. What differs Josh Groban from Bryan Adams? It's the vocal quality projected as well as the the breathing dynamics that sets the two apart.
Josh generates vocal power from the diapghram and breathes continuously. Bryan Adams on the other hand breathes profusely while compressing the throat to give out that husky, rocky voice that hase become his trademark.
Generating the voice through the mouth can be modified with the use of the nose. This is especially good for Altos and Tenors who are usually challenged to hit high notes above their regular ranges. It makes hitting high notes cleaner and simpler. It also elevates your facial muscles to make the sound brighter. (Boy, how difficult it is for a singer to break one's nose. Better find a good rhinoplasty in Oakland quickly. Hehe)