We seem to live in a world where a low, deep voice is prized as authoritative, grounded, imbued with gravitas--- however you want to say it, people tend to take it more seriously. Results from recent American psychological studies demonstrate that when listening audiences only have vocal cues, they would most likely hire, vote for and trust public speakers of both sexes who have low, deep voices, while they equate higher voices in public speakers with a lack of leadership ability.
Most likely because of this phenomenon, I have several clients at the moment who are working with me because they would like to sound more authoritative in professional contexts. Some of these clients are men but the majority of them are women because-- it must be said-- this 'low, deep' voice that connotes authority is likely based on a masculine sound. (If you're interested in that, Mary Beard gave a fascinating lecture about it in 2014 which you can read here. ) Some of my clients come not out of their own volition, but because their bosses have told them their voices are too high to sound authoritative, and they need to lower them in order to get ahead professionally.
Here's the thing-- many people hear that they need to 'lower their voices' to sound authoritative, so they go around trying to talk at a lower pitch. This road is neither comfortable nor authentic, and if you do it for too long, you could do some damage to your vocal folds. Your voice pitch refers to the frequency at which your vocal folds vibrate. We all have a 'fundamental frequency', which is your typical conversational pitch, and when we use pitch variation in our voices, you can think of that as variation upon the theme.
Where this lower 'authoritative' sound comes from is really the resonance of the voice. Resonance has to do with where you are feeling the vibration of your voice. There are three general areas where this vibration is easy to feel: in your chest, in your mouth and in your nose. If you start humming right now, you may even feel that buzz in all three areas. The 'low, deep sound' that is considered authoritative comes from having a combination of that mouth and chest resonance in the voice, meaning your voice includes a healthy buzz from both of those places.
Nasal/head resonance gives your voice a brighter, lighter quality. If you tend to have more vibration in your nose/head/face than in the mouth or chest, your voice will sound higher and younger to other people. While it's important to have all 3 areas of resonance in the mix, if you are a person who is frequently told that you need to sound more authoritative, here are some tips:
All this being said, I do think it is worth us examining-- what is an authoritative voice? It seems to be based on a masculine model, and I do think we should begin to question that. Can there be room for more than one type of authoritative sound? I hope so. I would love to hear your thoughts.
(image from http://content.time.com/time/magazine/article/0,9171,1871919,00.html)