An interesting definition of human voice is given by Sufi saint Hazrat Inayat Khan. It is true that our voices change according to a situation, although mostly it has one and the same melody, note or an element -as the saint depicts:
“There are five different qualities of the voice, which are connected with the peculiar character of the person.
The earth quality of the voice is hope giving, encouraging, tempting.
The water quality is intoxicating, soothing, healing, uplifting.
The fire quality is impressive, arousing, exciting, horrifying; at the same time it is awakening, because very often warning is given in the voice of the fire quality. The use of the words ‘tongues of flame’ in the Old Testament is narrative of that voice and word which were warning of coming dangers. It was alarming for the people to awaken from their sleep, to awaken to a greater consciousness, to a higher consciousness.
Then there is the air quality of the voice. It is uplifting, raising a person, taking him far, far away from the plane of the earth.
And the ether quality of the voice is inspiring, healing, peace giving, harmonizing, convincing, appealing; at the same time it is most intoxicating.”
Read more about human Voice here.