The woman that I know with the most beautiful singing voice, I've also heard reaming someone out and holy s*** does she have different voice she can draw on for the latter.
People usually speak in their 'normal'/'real' voice when they're angry.
Someone's singing voice is not always the same as their speaking voice. Another girl I know she speaks rather roughly and loudly. But she sings very well, and very softly and sweetly.
So your formal voice is also not always the same as your informal voice either (your informal voice being your 'actual'/'real' voice). The girl I spoke of now is usually very informal in her interactions, so she always sounds boisterous, but on the rare occasion when she speaks formally, her voice is closer to her singing voice, lower and softer. Myself, my actual voice is low-pitched and gruff, so much so that when I was younger my mother would chastise me for speaking roughly, but since I now speak formally with everyone – even my friends and family, with the exceptions of my siblings whom I do not meet for long stretches – most people only hear me in my soft-spoken high-pitched mode.
In a way it's a bit like acting; you exaggerate your voice for certain roles.
Now Michael Jackson's speaking voice was much like his off-stage persona: shy, retiring and absolutely zero personality. But once he was on the stage and/or started singing – oh, boy! he was an absolute ball of fire.
Which brings me to another point in my musings. Is your singing mode more representative of who you are than your speaking voice? For most people singing is their way of venting or expressing themselves, so one would assume they would do so in their 'real'/'authentic' voice, but doesn't the process of self-expression itself add a layer of artificiality to the expression? Whether there is any 'authenticity' to speak of when you consciously change your voice to express yourself?
Do you have a single voice you can point to and say 'This is me'? Or is a man no more or less than the sum of the masks he wears?