From:

Scientific American Magazine - March 1998, Pages 20-21

Unsound Reasoning -

Are Wind Musicians Loving Tropical Woods to Death?

At a recent conference on music and human adaptation at Virginia Tech, physicist John W. Coltman demonstrated what he first described in the early 1970s. After asking the attendees to divert their eyes, he played the same tune twice on the flute. He then asked whether anyone heard any difference between the two performances. No one spoke up; the two were virtually indistinguishable. Then Coltman revealed his trick. The first time he performed the tune, he played it on a simple side-blown flute made of lightweight cherry wood. The second time he used a flute of identical design, except for one detail: it was made of concrete.

To anyone schooled in the physics of wind instruments, Coltman’s point is old news. Whether the air is set to vibrate by an edge tone as on the flute, by a reed as with the clarinet or by buzzing lips as with the French horn, the sound itself comes from the vibrating air column inside the instrument. This sound is produced through the end or through open tone holes, not by vibrations of the instrument’s body, as is true of string instruments.

Dozens of published reports, some dating back 100 years, converge toward the same general conclusion: so long as the walls are thick enough to remain rigid—about 0.4 millimeter for metals, two millimeters for woods—and the inside walls are smooth, the kind of material is, for the most part, immaterial. But to many musicians, even a mountain of research remains unpersuasive. “We all know that wood flutes are much more dolce, much sweeter,” says flutist Paula Robison. In contrast, “a gold flute sounds like an instrument made of gold. The silver flutes are much more perky.”

The variation in timbre of wood and metal instruments stems from differences in acoustic dimensions brought about by the manufacturing process, not by the materials per se, says Robin Jakeways, a physicist at the University of Leeds. For example, holes in wood flutes are simply drilled in, whereas metal flutes have holes enclosed in a short length of pipe. Brian Holmes, a physicist at San Jose State University and a professional horn player, cites a study that found that plastic and metal clarinets had tone holes with much sharper edges than their wood counterparts. When these holes were rounded off, these clarinets sounded much more like wood ones.

Materials also differ in their ability to conduct heat and vibrations. “While those vibrations may not affect the sound significantly, they certainly affect how the instrumentalist interacts with the instrument,” Holmes explains. After spending a premium for an instrument made of expensive material, it’s only human to convince yourself that you must sound better. And, as flutist James Galway points out, the workmanship of an instrument made of $70,000 worth of platinum is likely to be of extraordinarily high quality. “People pick up my flute and say, ‘This is better.’ Of course it’s better; it’s like getting into a custom-built motorcar,” he says.

Whatever the underlying reasons, the devotion of many musicians to rare or precious materials could help contribute to their extinction. Dalbergia melanoxylem, known as M’Pingo, granadilla (African blackwood) and D. nigra, also called rosewood or palisander, are considered endangered, says Richard F. Fisher, a forest scientist at Texas A&M University. Grenadilla is the wood of choice for clarinets, oboes and, increasingly, wood flutes and piccolos; rosewood is a favorite for recorders.

Although the demand for fine musical instruments might seem too small to inspire a debilitating harvest of the rain forest, Fisher asserts otherwise. To get to the remote regions where these trees grow, harvesters must clear rivers or build roads. “In many of these areas there are so many landless peasants looking for a piece of land to farm that after you remove just the few trees you want, they go in and invade because now they have access,” Fisher says. “They cut down the rest of the forest and start to grow crops.”

Fisher adds that these tropical species are extremely difficult to raise on plantations. They take 60 years or more to reach maturity and tend to grow poorly when raised clustered together in stands, as their key defense against predation is being scarce in the forest. Indeed, an instrument maker in Libertyville, Ill., Boosey and Hawkes, failed at replenishing M’Pingo trees, says François Kloc, a master craftsman there. To offer an alternative material, the company developed a “green” line of oboes and clarinets. These instruments are made of M’Pingo sawdust and a patented mixture of carbon fiber and epoxy glue that is heat-treated and placed in a press to give it the density of whole wood. This process enables the company to use all of the tree instead of only the prime 20 to 30 percent that was usable before. Old, damaged clarinets can also be recycled in a similar way to make new ones.

Whether such innovations will ultimately be widely accepted by music lovers remains to be seen. “Most musicians and many listeners believe without question that the material of which a wind instrument is made has a profound effect on its tone quality,” Coltman remarks. “After 100 years, scientists have still convinced nobody.” — Karla Harby in Rockville Centre, N.Y.