John Scott vividly remembers the presentation he gave last March in a competition with three other finalists for a $5 million grant from the Life Sciences Discovery Fund. He didn't win. “I felt I did not put my best foot forward,” he says. Part of the problem, he believes, was his voice. Colleagues have hinted that his presentation voice is too quiet and monotonous, he says.
Scott, an assistant professor in medicine at the University of Washington’s Harborview Medical Center in Seattle, turned to Jan D’Arcy , a movie and TV actress who runs a speech coaching agency. D'Arcy taught him how to conquer his fear of public speaking and how to use his voice better during presentations.
Scott isn’t the only scientist D’Arcy has trained. Among her clients are NASA astronauts and biotech higher-ups who sought her help to make their voices sound more authoritative.
A voice coach like D'Arcy can be helpful but may not be necessary. It's possible to make improvements in your voice independently. And that, in turn, can make a big difference in your career, our sources say.
A growing body of evidence from multidisciplinary research in acoustics, engineering, linguistics, phonetics, and psychology suggests that an authoritative, expressive voice really can make a big difference. “There are scientific studies that show that the characteristics of somebody with authority is that they speak very low, slow, and with intonation,” explains Benoit Curdy, a computational linguistics graduate from Lausanne University  in Switzerland who co-founded the computerized voice coaching start-up Vocalytics  in Dublin. A good example of an authoritative voice, Curdy says, is the voice on the New York subway that says, "stand clear of the closing doors." 
Culture has an impact on voice preferences, Curdy says. They vary from place to place. But in most of the West, the preference is consistently for low and slow. Scientists at the Center for Voice Disorders  at Wake Forest University in Winston-Salem, North Carolina, found that what U.S. audiences perceive as the “worst voices” are those that are high-pitched relative to gender norms, or screechy because of high-frequency noise. “Listening to a badly tuned voice is like a badly tuned radio,” says Alan Mars , a voice coach based near Brighton in the United Kingdom. “It tends to get people to switch off .”
“We tend to think of the human voice like eye color or the fairness of your skin, but voice is a muscular mechanism and, as such, it is amenable to training,” Mars says. Adds D’Arcy, “Your voice will be [made] more expressive by improving your breath control and working on rate, volume, pitch, quality, and articulation.” While these aspects are related, they may be worked on separately, D’Arcy says.
The first thing scientists need to realize is that fear of speaking affects their voice. “I found that scientists and engineers did not want to be in the spotlight, so they were very nervous,” D’Arcy says. “To improve their voice,” she says, “they have to minimize the tension in their body.”
Start with your posture. Undesirable “postural habits shorten, narrow, and twist what I call the human sound box,” Mars says. “The very first postural landmark is very consciously distributing your weight between the left and right foot and balancing from the heel to the root of the toes,” he continues. D'Arcy adds that you should stand upright so that your lungs can expand freely.
Standing up straight, with your weight properly distributed? It's time to work on your breathing. A person with a voice that's pitched too high usually isn't breathing properly, D'Arcy says. In fact, "everything which is related to pitch, rate, and volume goes back to breathing."
The key, D'Arcy says, is what she calls diaphragmatic breathing , in which the stomach, not the thoracic cage, moves out when you breathe in. Lie down and put one hand on your chest and the other one on your stomach. As you slowly inhale, your stomach should expand and your chest should hardly move.
Poll Moussoulides, CEO of voice-coaching agency Voice Matters  in Dublin, says that just breathing more deeply can improve your voice. Better breathing provides “better support for projection and applied use of vocal variables (pace, pitch, volume). It builds up the musculature and gives your body the ability to respond to demands of public speaking and effective communication,” he says.
If you're not sure what aspects of your voice you need to work on, compare your voice with the voices of good public speakers, especially “people passionate about what they are saying,” D'Arcy says. She recommends TED Talks , since the speakers there tend to be very good.
Talking too fast -- especially in stressful circumstances -- is a common problem. “You need to develop your own internal sense of timing,” D’Arcy says. She advises getting feedback on your performances from a trusted peer. Recording a presentation can help you identify whether the pace is too quick, and more importantly, too steady, Moussoulides says. He s speakers aim to vary their pace so that 70% of the speech is relatively slow -- but 30% is faster. Slow passages draw attention to important ideas; contrasting faster passages suggest passion.
Another common problem is talking too softly. “Most people, if they want to be heard, force their voice,” D’Arcy says. But forcing causes the voice to be produced mainly in the throat, and “when you [only] use your throat, you switch off your resonator.” Improving posture and breathing technique will go a long way toward improving resonance. Yawning on purpose can relax the pharynx and improve resonance. Mars recommends exercises singing scales with vowels, following the example of the late opera singer Luciano Pavarotti .
If you find that your articulation also needs improving, do “articulation exercises exaggerating consonants and vowels and exercise reading tongue twisters  out loud to loosen stiff jaws, lazy lips, and a sleepy tongue,” D’Arcy suggests.
While it's true that some people's voices are naturally higher than others, problems of pitch -- and the lack of credibility that often results -- tend to arise not from absolute pitch but from speaking at a pitch that's not appropriate for your natural voice. “If it is too high or too low, the waveform [of your voice] will be flattened,” and you won't be able to modulate your tone, Mars explains. Moussoulides suggests identifying your natural mid-note this way: It's the pitch of the second syllable when making the “uh-huh” agreement sound during a conversation. That's the center of your range, your starting pitch.
Next, learn to vary your pitch expressively. “If you are trying to get across a critical recommendation, your vocal pitch [needs to give] emphasis to the word that matters,” D’Arcy says. Curdy recommends Praat , a free online application developed by Dutch voice analysis researchers, which “gives you a sense of how to modulate your intonation.”
An excellent all-in-one exercise, Mars says, is reciting Shakespeare’s “Sonnet 18"  (also available in modern English).  By making this a daily practice, you can work on breathing, rate, and articulation all at once: The 10-syllable lines are short, but each "is a sufficient pack of information." The space between the lines allows you to focus on breathing, as "your audience takes it in,” he explains. The sonnet is great for practicing modulation by "going higher, lower, or very quietly as appropriate,” he adds.
For those who want to know more, D’Arcy’s book Technically Speaking  is available now. Both Mars and Moussoulides have books coming out later this year.
“To draw the listener’s ear to the salient points of your presentation, you have to do something with your voice to entice the audience to listen and focus,” Moussoulides says. “In the same way that stage makeup looks gross and exaggerated but looks natural from afar, when you go to a larger public, your presentations, your expressions, your variation in vowels, your pitch [and] rhythm need to be somewhat more marked,” Mars says. “Exaggerate the consonants and elongate words when you come to important parts,” D’Arcy advises.
By working on his voice, Scott became a better and more confident speaker, so now he enjoys speaking and does it more often. His new focus on communication -- and the work he's done on communicating ideas carefully and clearly -- have even improved his thinking, he says. “It challenged me in how I approach my science. It has helped me clarify my thinking about my research,” he says. “If you are investing time developing [scientific] techniques and applying for grants, you need to invest in gaining tools to make sure your research is understood. It is just as important as to write a grant.”