You're right, a "loud" voice doesn't sound the same as a quiet one. Even if you modify the volumes to be the same. There's also acoustic effects caused by havin

You're right, a "loud" voice doesn't sound the same as a quiet one. Even if you modify the volumes to be the same. There's also acoustic effects caused by having a microphone close to your mouth. However, a good measure is: how far away from their mouths is the microphone? The answer is: when singers go into the "belter" part of a song, they put more distance between them and the mic, because otherwise they'd be too loud. I'm no professional, but I've done some proper singing in my time and it's exhausting (to an extent unappreciated even by other musicians). I can probably count myself lucky I had a vocal coach who stressed _minimizing_ the amount of air you use for a note.