The natural range of the human voice is produced only by learning to always ever use the least amount of tension of the vocal folds and the least amount of breath of each and every tone. Nature is ever efficient.
Breath is clearly a key to voice generation, though not the essential power which many approaches teach today. Contrary to popular opinion, singing develops the cardio-vascular system, which includes our lungs and it’s generating power, similar to any physiological process which develops the organ from which it takes place. So it is not breathing that develops singing, but singing that develops breathing.
The most important focus in voice production is resonance*1. It provides the voice with volume, loudness*2, and quality. It is therefore essential to rely on resonance rather than force in generating a big and pleasing which reflects you both emotionally and psychologically.
Singing and speaking are similar physiological processes and are therefore the same process.
The speaking voice acts as the key factor of the singing voice and makes-up its true support. In its very nature, singing is actually merely speaking in musical rhythm. And so, no accurate singing can exist without an accurately produces speaking voice.
*Resonance: a sound or vibration produced in one object that is caused by the sound or vibration produced in another.
*Loudness: the characteristic of a sound that has primarily a psychological relationship to physical strength (amplitude)
(c) David Delaney, 2014
Adapted from the work of Mario Marifiotti: Caruso’s Method of Voice Production, Dover Press.