Does material affect tone quality in woodwind instruments?: Why scientists and musicians just can’t seem to agree
MARCH 1, 2007~
BRET PIMENTEL
Most woodwind players would be surprised if you asked them whether the material from which their instrument is made affects its sound.
Certainly!—most would reply. An inexpensive nickel-plated flute has a tone lacking in character and brilliance, but a fine silver flute sounds, well, silvery! It has a tone that sparkles, that sings, that carries to the back of the concert hall. The most discriminating flutists might opt for the more luxuriant timbres of white, yellow, or rose gold, or even the rare and weighty quality of platinum.
And any self-respecting oboist or clarinetist would refuse to even
consider an instrument made of lifeless black plastic. Only the finest aged African blackwood can provide the dark, rich, woody tone that a true artist requires. Bassoonists likewise insist upon bassoons made from the best maple, and preferably treated with a secret-formula varnish, which, like that of the famous Stradivarius violins, is rumored to impart a special vividness and resonance to the instrument’s sound.
And fine saxophones, though most often made from brass and lacquered in a gold color, can be special-ordered in silver or even gold plate, which, saxophonists just
know, bestow a unique sonic personality. Some saxophonists are willing to pay a premium for certain hard-to-find French instruments made in the decade following World War II, which are reported to be made from melted-down artillery shell casings, and to have a correspondingly powerful quality of tone.
It seems to many musicians a self-evident truth that premium materials produce a premium sound. But scientists have believed for years that a woodwind instrument’s material has virtually no effect on the kind of sound the instrument produces.
Unsurprisingly, the scientific view has not been popular with the woodwind-playing crowd. Most have invested thousands of dollars in their personal instruments made from the rarest woods and shiniest jewelry metals. Most have been taught the subtleties of instrument selection by wise and respected teachers, and have dutifully passed the knowledge on to their own generations of students. But most of all, they have heard with their own ears the difference between a silver flute and a gold flute, or a plastic oboe and a wood one. They have held the instruments in their own hands and felt, deep in their gut, that different materials just sound
different.
Theobald Boehm, the 19th-century flutist and metalsmith who virtually invented the modern flute, held to this idea. He wrote in 1871,
The greater or less hardness and brittleness of the material has a very great effect upon the quality of tone. Upon this point much experience is at hand. Tubes of pewter give the softest, and at the same time the weakest, tones; those made of very hard and brittle German silver have, on the contrary, the most brilliant, but also the shrillest, tones; the silver flute is preferable because of its. . . unsurpassed brilliancy and sonorousness; compared with these the tones of flutes made of wood, sound literally wooden.1
Clarinetist Geoffrey Rendall, writing in 1954, said that clarinets made of ebonite (a hard rubber compound) “somehow seem to lack the carrying power and expressiveness of wood.”
The tone can be taken just so far and no further. It lacks life and is no longer popular with professional musicians. . . . What has been said of ebonite may be said of metal. . . . it has the slight deadness of ebonite. . . 2
The woodwind player and historian Anthony Bates said in 1967 of the clarinet,
. . . [It] has a cylindrical tube . . . of African blackwood, which has replaced cocus; though possibly none of this jungle wood can rival the old Turkish boxwood, which for some reason gave especially fine results in clarinets. . . Many fine players have played on ebonite, which gives a sweeter though rather smaller tone than wood. Metal, on the other hand, does not seem to offer the right resistance, giving a tone that feels to most players rather vapid and uninteresting, and it is not used for high-class work.3
So why do scientists insist that material is effectively irrelevant?
Many woodwind players assume that, say, a clarinet vibrates like a violin soundboard or a drumhead, transmitting sound waves into the surrounding air. And, in fact, a clarinetist can
feel the instrument vibrating in her hands when she plays.
The mistake here, according to scientists, is thinking that the vibrating instrument is what is producing the sound. Basic acoustics tells us that the woodwind instrument is merely a container for the real sound-producing body—a vibrating column of air.4
A number of scientists have undertaken to prove empirically that characteristics of a woodwind instrument’s sound are affected only by the characteristics of the air column. But there are several factors which make this a difficult proposition.
First, as every woodwind player knows, no two instruments play alike. Fine woodwind instruments vary from specimen to specimen. These variations range from the easily visible to the virtually undetectable, and interact in complex ways to affect the sound of the instrument. In order to accurately test the effect of wall material, these instrument-to-instrument variables must be eliminated.
A particular difficulty with eliminating these variables in woodwind instruments is the question of the instrument’s pads. Woodwind instruments have toneholes that are opened and closed by pads made of cork or animal skin. These pads are installed by hand by specialized craftsmen, and the process is widely regarded as more of an art than an exact science. Small variations in the organic materials involved, and in the pads’ installation, can cause very noticeable differences in the way each instrument plays.
A second consideration is the human physiological factor. A woodwind player’s embouchure—the way he uses the complex system of facial muscles to form an interface with the mouthpiece—is, as he will ruefully tell you, highly variable. Even the finest and most consistent players change their embouchures, at least imperceptibly, from moment to moment. Many of these subtle changes are made intuitively and without the player’s awareness of which muscles are being used, or maybe even that they are being used at all. The complex human respiratory system adds another comparable layer of problems. The human anatomy presents a highly complicated and hard-to-measure set of variables that must be dealt with in order to construct a scientifically acceptable experiment.
A third and even more mysterious factor is the influence of human psychology. Any bias on the part of woodwind players or listeners can affect their perception of an instrument’s sound. A bassoonist, for example, might consciously or unconsciously expect that, say, a bassoon with richly grained wood might have a “fuller” sound, or that a plastic bassoon will just sound more “plasticky.” The simple expectation of hearing a certain sound may influence the bassoonist (or a listener) to project that expectation onto the actual sound heard.
In a 1964 experiment, University of Southern California physicist Dr. John Backus attempted to determine the role of a clarinet’s body vibrations in sound production.5 Backus’s experiment centered on a clever and slightly comical gadget, with an artificial embouchure powered by a household vacuum cleaner. The clarinet’s tone holes were all closed (simulating a clarinetist playing the instrument’s lowest note), and the bell of the instrument was fitted with a muting device. When the clarinet was “played” via vacuum cleaner in this way, no sound waves could pass from the air column inside the clarinet directly into the air surrounding the instrument. Backus found that in this situation the instrument was virtually silent; the vibrating wood of the clarinet emitted such weak sound waves as to be inaudible to a human ear at a distance of one inch from the instrument’s body. Backus concluded that the wall vibrations of a clarinet are too small to produce a perceptible sound. Further, he speculated that if it were possible to make the instrument vibrate sufficiently to be heard, the consequence would not likely be a pleasant one; he pointed out that a similar phenomenon occurs when one of the instrument’s keys works loose and causes an annoying buzz. Backus’s further research reveals that the instrument’s body vibrations are due to the reed vibrating against the mouthpiece, not due to the vibrations of the enclosed air column.6
In 1971, the
Journal of the Acoustical Society of America published a study by Dr. John Coltman, a physicist and researcher for the Westinghouse Electric Corporation.7 Coltman, an amateur flutist, attempted to test the sound properties of different woodwind wall materials while minimizing the effects of instrument variation, physiology, and psychology. Coltman’s experimental apparatus matched Backus’s for both ingenuity and hilarity, consisting of three cylindrical tubes: one of silver, one of copper, and one of blackwood, all identical in inner diameter. Each tube was fitted with an ostensibly identical flute headjoint made of Delrin plastic. The three flutes were arranged so that their headjoints passed through a shield, blocking the tubes from the flutist’s view, and the entire contraption was mounted on a central rod, which the player held onto (so as not to touch any of the tubes) and rotated to bring each of the headjoints into playing position.
In the first phase of the experiment, a panel of listeners (including nonmusicians and musicians, some of the musicians being flutists), was asked to listen to sets of three sample notes or groups of notes. Two of each three samples were played on one flute, and one sample was played on another, and the listeners were asked to identify which sample was played on a different flute than the other two. The results? The listeners were correct about one third of the time, the same result that would be expected from random guessing.
In the second phase of Coltman’s experiment, trained flutists were asked to blindly play each of the three flutes, and select one which they thought they could identify again. Then the flutists were instructed to spin the rod quickly so as to lose track of the selected flute, and then find it by playing each of the flutes again. Again, the results were essentially on par with random selection. Coltman interpreted these results to mean that neither flutists nor listeners could accurately identify a difference in sound between the three materials.
Decades of similar studies, especially the continued work of Backus at the University of Southern California, confirm and refine these results. But though the scientific evidence seems overwhelming, musicians still insist they can hear a difference. It is possible—even likely—that wall material
does influence an instrument’s sound, but only in a number of
indirect ways.
Materials may affect they way an instrument sounds before anyone ever plays it—by affecting the way the instrument is made. For example, some woods may respond better to instrument makers’ drills and reamers, and thus more faithfully reproduce the desired bore shape; certain metals may likewise cooperate better in taking the desired form. Or perhaps more expensive materials make better-sounding instruments because makers handle them with an extra measure of care. In the case of plated flutes or saxophones, instruments that seem to play especially well may be selected by the maker for a special finish of some precious metal.
It is also possible that the vibration of the instrument’s body is, in fact, audible to the player through the phenomenon of bone conduction, in which sound waves are transmitted through the bones of the head to the inner ear. If this is the case, it is possible that the instrument’s vibrations are minutely audible to the player. As Backus points out, there is no reason to believe that audible instrument body vibrations would be an improvement, but in any case the vibrations could conceivably affect the player’s perception of tone, and thus even affect his approach to playing the instrument, indirectly affecting what the audience hears.
But the most convincing theory of why musicians are so sure about gold flutes and maple bassoons is that the materials do, in many ways, affect the way the player feels. And, as any musician will tell you, nothing affects the music more than the way the musician feels. The smooth, polished wood of a fine oboe, the patina of the silver keys, even the gold of the maker’s emblem, lend the oboist confidence, comfort, perhaps a sense of luxury?—that come through in the way he or she plays.
While it seems clear from scientific investigation that, all else being equal, materials make no difference to a woodwind instrument’s sound, it seems equally clear from musical experience that all else is never equal. Factors as small as the precise brass alloy of a saxophone’s body can make all the difference in the world—not because of any acoustical effect, but because of the undeniable human element. So if you feel, deep in your heart, that a platinum flute or a rosewood oboe or a silver-plated saxophone will make you sound better, then it probably
will make you sound better.
Woodwind players will continue to play the instruments that feel and sound right to them, no matter what the scientists have to say. And so they should! A musician’s instrument is the tool of his or her trade, a treasured possession, and a nearly constant companion. But perhaps a levelheaded understanding of the role of materials in a woodwind instrument’s sound can lead to better instruments—and better musicians—in the future.
Notes
1. Theobald Boehm,
The Flute and Flute Playing in Acoustical, Technical, and Artistic Aspects (New York: Dover Publications, 1964).
2. F. Geoffrey Rendall,
The Clarinet: Some Notes Upon its History and Construction (New York: Philosophical Library, 1954), 14-15.
3. Anthony Bates,
Woodwind Instruments and Their History (New York: Dover, 1967), 117.
4. See, for example, William J. Strong and George R. Plitnik,
Music – Speech – Audio (Provo, UT: Soundprint, 1992), 307-315.
5. John Backus, “Effect of Wall Material on the Steady-State Tone Quality of Woodwind Instruments,”
The Journal of the Acoustical Society of America 36, no. 10 (1964 ): 1881-1887.
6. Ibid., 1883-84.
7. John W. Coltman, “Effect of Material on Flute Tone Quality,”
The Journal of the Acoustical Society of America 49, no. 2 (1971): 520-523.
