When it comes to the speaking voice, those which are most appealing to your ear tend to be deeper in pitch. Think of Sam Elliott, Felicia Rashad, Diane Sawyer and James Earl Jones. All of these voices have a depth and breadth that you do not hear with the likes of Fran Drescher or Don Johnson.
Drescher and Johnson exhibit a great deal of nasality in their tone which makes their voices sound higher in pitch because of how their sound is produced – through the nose. [Incidentally, pitch refers to the highness or lowness of sound. Volume, on the other hand, deals with the loudness or softness.]
In addition, voices which are produced high in the mouth and/or nose often result in a strident, shrill, or whiny quality which is not pleasant to the listeners’ ears.
Because Elliott, Turner, Sawyer, and Jones are powering their voices primarily by means of their chest cavities and not their mouth or nasal cavities, their voices have resonance and warmth. When you hear Diane Sawyer speak, it is like a blanket around your shoulders. It is an warm, comforting sound. High-pitched, nasal, or strident voices, for example, do not exhibit those attributes.
Resonant voices are akin to a cello or bass – they resound.
If you are not using your chest as your primary sounding board, then the pitch of your voice is probably higher than it should be. Once you discover your optimum range, however, you will find that your voice is lower in pitch. it may be a mere ½ step or it could be several steps. The resonance occurs when your chest cavity is powering the sound which falls within your optimum range.
If you are willing to break some old habits and instill some new ones, you can have that resonance as well. Which would you prefer? The warm, lush tones of a cello or bass or the quawk of a poorly-tuned violin!