Denver, the capital of the western state of Colorado, boasts America's largest publicly - owned center for the performing arts. The facility, that includes eight theaters and a large ballroom, can accommodate 10,000 visitors. But the organization that makes the Denver Center for the Performing Arts really special is its Voice Center, a research and clinical facility specializing in the human voice. How handy for singers and actors requiring assistance while performing in Denver. But the Voice Center also helps people with serious communication problems.
Three tenors are singing the most famous aria from Puccini's opera Turandot. These, of course, are not the world famous tenors Luciano Pavarotti, Placido Domingo and Jose Carreras. Two of them are researchers at Denver's Wilbur James Gould Voice Center and the third is Pavarobotti, a computer program that imitates a tenor's voice.
Ingo Titze, the executive director of the Voice Center, says no one's voice was recorded to produce Pavarobotti's sounds. "It [the robot] was told where the notes are and it was told where the rhythm is," he said. "But as far as the sound goes, that comes all from just waves bouncing around in an airway."
Researchers at the Voice Center have created a computer-model of a human throat and mouth, complete with all the elements that produce sounds, such as the larynx, the vocal folds, the air passages and the tongue. Peter Popolo, a researcher and one of the three tenors mentioned above, says they have pre-programmed it to sing the hardest parts of Puccini's aria. "And we even programmed him to hold the note at the very end the high B-flat for something like 25 seconds, which is almost impossible [for a human]," he said.
The Voice Center researchers are currently working on developing similar programs for sopranos, altos, baritones and other singing voices. The programs are aimed at helping teachers of singing. Unlike the guitar or the violin, the vocal instrument is hidden inside a person's body. Ingo Titze says showing it on the screen while it produces different sounds and comparing this with an idealized, computer-created vocal apparatus, can be a powerful learning tool. A singer or an actor, for example, can come to the Center where experts will examine the magnetic-resonance imaging of his or her vocal organs in the act of producing sounds.
"And then we would take that and simulate their voice first and once we get what their dimensions are, then we can say OK - if we did some training on vibrato, or we did some training on the ring in the voice, or we did some training on maybe increasing the warmth of their sound, or whatever - then we could do that one parameter at a time as we call it," said Ingo Titze.
Voice is represented on the screen with a set of parallel waves - some thicker than others - of various shades of blue. Here's what these waves may reveal about a complete novice coming for voice evaluation.
Perhaps more importantly, the Voice Center offers help to people with vocal disorders such as hoarseness, wobbling and slurring. Dr. Titze says computer programs can predict what speech therapy will be able to correct.
The Center has had great success in developing vocal rehabilitation programs for people whose communication was diminished by Alzheimer's or some other disease.
Last year, the Wilbur James Gould Voice Center received a grant from the National Institutes of Health in Washington D.C. to study voice use in teachers. Teachers, coaches and other people who use their voice a lot on the job, often develop complications in their vocal tract. The goal of the program is to provide guidelines for safe voice usage.
Ingo Titze says the major discovery so far has been that the limit for safe voice usage can be measured in terms of the distance that the vocal folds can safely travel. "They travel back and forth," he said. "They don't go anywhere, but they move and that [the distance they can safely make] is approximately half a kilometer. And then they need rest."
Half a kilometer is about 17 minutes of non-stop speaking. In real life it never happens because people have to stop to take a breath. Dr. Titze says it is yet to be determined how long the periods of rest need to be to keep the vocal folds unharmed.
The Denver Voice Center has already developed a dosimeter, a small computer that a number of Denver public school teachers will carry with them this fall. Engineer Peter Popolo says the dosimeter will measure the use of the teachers' voices from the time they get up until the moment they retire for the night, for two weeks at a time.
"It allows us to measure, during the day, three important vocal characteristics: their speaking pitch or fundamental frequency of their voice, the intensity or loudness of their voice and how much time they actually spend during the day vocalizing and phonating [using their voice] and how much time they are at rest," he said.
Researching how teachers use their voice is just one of the many programs of Denver's Wilbur James Gould Voice Center, whose goal is to enhance the use of human voice.