Don’t be deceived about the “size” of commercial voices you hear on recordings. They are sometimes produced in the studio to sound big and thick and bright. If you heard these singers in your average-size living room, you may be shocked to realize they sound nothing like they do on recordings.
This is, in fact, part of the perception problem that happens when we try to copy some of our favourite singers. We try to mimic what we think is the singer’s vocal power, when it is actually an illusion of power created in the studio with amplification and effects. Even on our favourite shows like American Idol and The Voice, there is tons of reverb, delay and EQ effect added to a singer’s voice to make it sound “larger” than it really is.
What makes a great “big” voice is a singer’s ability to control their voice during register shifts, changes in volume, and use of correct resonators. These things can only be done well when a singer’s larynx and vocal cords are in good shape. These abilities have nothing to do with whether a voice is actually “big” or not. (A big voice is when a person is loud when they are talking … not just singing … and this usually means they have thick vocal cord).
Amplify a voice that has great control of the above qualities, and you get one heck of an awesome voice. And yes, this voice can be “big”.