ABC's hit TV-series "Making the Band has produced a group called LMNT (pronounced "element"). The band tells how physics helps their music.

How the voice box works

The voice box, or larynx, is a funnel-shaped organ held together by rubbery cartilage, it houses the vocal cords and throat muscles, and connects the base of the neck to an air tube called the trachea. Air from the lungs strikes the vocal cords to produce sound.

Mike Miller's VOICE BOX

"I was the kind of kid who went around the house singing all day," says Mike Miller, 20, of Morristown, N.J. When he belted out a solo in a sixth-grade musical production of Grease, admirers poured backstage to tell him he had a "great voice and to stick with it." What the audience actually heard was the action of air moving through Miller's voice box, or larynx--a group of muscles, bone, and bone-like tissue called cartilage, visible in his throat as his "Adam's apple." That's where air from Miller's lungs starts to make some noise.

As air moves through Miller's vocal cords or folds (two membrane-covered muscles that open and close across the passage to the lungs), they vibrate like flags in the wind. The flapping creates pulses of sound (see diagram, p. 19). Miller adjusts the shape of his throat, mouth, tongue, and lips to create different musical sounds.

A decade after his debut, Miller's voice has developed with years of exercise into a booming bass, singing the lowest: notes in the band.

What determines Miller's range, or notes the singer can hit? Mainly physical factors, such as the length of the vocal tract (the distance from the larynx to the lips) and vocal cords. "Basses have the longest vocal folds," says Richard Lissemore, LMNT's voice teacher. "Sopranos [female singers with the highest voices] have the shortest ones."

A singer's vocal range is the result of tension in the vocal folds, an action you learn to control unconsciously from the time you start to talk. Tight vocal folds flap quickly as air passes through them. The faster they flap the more vibrations they produce. The more vibrations, the higher the singer's range.

Matt Morrison BREATHES EASY

After a stint in a Broadway musical, Matt Morrison says the most important thing he's learned about singing is how to breathe properly. "You fill up your whole mid-section. Even your back expands," he says of his technique.

In normal breathing, you use the diaphragm (muscles and connective tissue between the chest and abdomen) to inhale, explains communications science professor Charles Larson at Northwestern University in Evanston, Ill. Singers use abdominal muscles to push the diaphragm up against the lungs. This creates air pressure in the chest, which sends a constant stream of air through the larynx, giving singers control of their airflow.

With so much emphasis on breathing, the guys in LMNT exercise daily to stay in top physical shape--they run and play basketball, among other sports. They also sing scales to adjust the tension in their vocal folds as each strives for a different pitch. Voice teacher Richard Lissemore calls these vocal exercises vocalises. "They exercise different muscles of the larynx," he says. "Muscles learn by repetition."

Bryan Chan: PITCH HITTING

The guys in LMNT sing four-part harmony: four voices croon different yet complementary notes at the same time. Bryan Chan, 26, sings baritone, which puts his voice between Miller's bass and LMNT's two tenors (higher male voices), Morrison and Kahoano. For their voices to blend, says Chan, "I've got to be able to hear everyone else's pitch to stay on key."

Again, what you hear as sweet harmony are sound waves, which travel through air at 340 meters (1,115 feet) per second. Your ears translate the vibrations into signals your brain recognizes as sound.

Think of a Slinky. Stretched out, it acts like a tube of air molecules. If you push on each end of the Slinky, your hands' energy ("sound") forces the coils ("molecules") together--called compression. Then coils push apart to form rarefaction, or expansion (see diagram below). This push-and-pull of molecules keeps energy moving from the source of sound waves to your ears.

The musical pitch of a sound depends on how quickly sound waves travel through air, which is measured by frequency (vibrations per second). When Chan sings, the faster his vocal cords flap the higher the frequency of vibrations hit your ears--and the higher his note sounds. The typical adult male singing voice produces 110 vibrations per second, while adult females generate about 200 vibrations. "To try to hit high notes people stand on their toes to force the air out of their lungs as hard as they can," says Chan.

Ikaika Kahoano: ON SINGING WITH SOUL

Ikaika Kohoano has had a lifetime of singing practice. As a child, says the Hawaiian-born singer, "I just opened my mouth, and it sounded good." Easy for Kahoano to say. His mom's a singer and his dad a radio DJ. But it doesn't take a musical--or even human--family to be able to belt out a tune. "A dog's howls and chimpanzee's hoots could be called singing," says biologist Tecumseh Fitch at Harvard University in Cambridge, Mass. Such sounds "require a high level of vocal control," and all mammals share a similar anatomy for vocalizing, or using their voices.

New studies show that music, like speech, comes naturally to humans and is hard-wired into the brain. Babies who coo and cry can recognize various kinds of music.

If humans are physically equipped to sing, why do so many people think they cant't? Turns out, it may be stage fright. "As long as you can speak and hear well, you can be trained to control your voice," says Charles Larson.

Like gifted athletes, great singers have "gifted control over their vocal muscles," Larson says. These stars may be born with more sensitive vocal muscles, he says, but no scientific proof yet exists. "But with proper training they can sing in a way the rest of us only wish we could."

How the diaphragm works

To belt out a song you use your ribs, lungs, and diaphragm, a dome-shaped muscle that pulls air into your lungs. When you inhale, your diaphragm flattens (left) and expands your lungs so they can hold more air. As you exhale (right), your diaphragm springs back to its dome shape and drives air out of your lungs, through your voice box, and out your mouth and nose.

How sound waves work

You hear sound because invisible waves pulsate from a sound source to your ears, causing them to vibrate. Differences in sound result from changes in the shape of the waves. A wave's amplitude, or height, creates a sound's volume. A high-amplitude wave is loud, while a small-amplitude wave is quiet. A sound's pitch is created by the wave's frequency, the distance between two waves. Waves close together create a high-pitched sound.