By Fan-Chia Tao
One of the most frustrating problems for violinists is the whistling open-E string. Indeed, when crossing from the A string to an open E, or playing a chord in Bach, players are often seized with fear that their E string will whistle. While there’s no foolproof cure for a whistling E string, understanding a little about how bowed strings work can help solve this problem—and may explain why whistling is not necessarily a sign of deficient bow technique. After all, I’ve heard some of the world’s finest violinists whistle their open E-string in concert.
The Science of Strings
You’ve probably noticed that whistling rarely occurs with stopped notes. That’s because your fingertip provides a high degree of damping (damping is how quickly the vibrations die away).
The cause of a whistling E string is the string vibrating differently than intended. Normally, a bowed string vibrates in a side-to-side (or transverse) motion, producing a saw-tooth shaped waveform called “Helmholtz motion.” When the string vibrates in a torsional (or twisting) motion, rather than the normal side-to-side motion, the open-E string whistles.
The torsional vibration frequency for an unwound plain steel E-string is approximately 4,800 Hz (an open A is 440 Hz), and independent of the string’s diameter or tuning. This is the high-frequency pitch you hear. The torsional damping of steel wire is extremely low, which means that once a string starts torsional vibration, it does not stop quickly.
Your lower strings don’t have a whistling problem because their windings provide high torsional damping and their construction moves the frequencies to a much lower frequency. (Lower strings can still squeak, but this type of squeaking is different—it’s a transverse motion caused by low transverse string damping and poor bowing technique.) That’s why a wound E-string is more whistle-resistant—some wound E-strings are practically whistle-proof, and the only guaranteed way of preventing whistles. However, a wound E-string generally sounds warmer and less bright, and many players prefer the bright sound of a plain steel E-string. There is anecdotal evidence that a gold-plated E-string is more prone to whistling. If true, it might be due to the smoothness of the gold plating, which reduces torsional damping where the string rubs against the nut and bridge string notch.
It Starts with Rosin
Rosin is the key to producing the desired sound and its importance is illustrated by the inability of a freshly rehaired bow, one with no rosin, to vibrate a string. (So let’s retire the old myth that little “hooklets or scales” on the bow hair cause the string to vibrate.)
Anything that detracts from the proper starting of a note, such as dirt or oil on the bow hair, or insufficient (or even too much) rosin, will contribute to whistling. But even a perfectly rehaired and rosined bow is not immune.
Violin setup affects whistling, but there is no single violin adjustment that will prevent it in all cases. In some instances, an adjustment that prevents whistling might make something else worse. Therefore, luthiers will go through a lengthy list of adjustments, including soundpost, bridge setup, changing the shape of string notches, the tailpiece assembly, and so on, in hopes of finding a cure.
Using Your Technique
Let’s assume that your violin and bow are in optimum condition, and you prefer a plain steel E string, but it still whistles. What can you do with bowing technique?
Quick-and-clean starts of normal bowed notes require not only the correct amount of bow pressure and speed, but also the right amount of bow acceleration from zero speed. When the bow is already moving and contacts the string (such as crossing to the open E string from the A string), conditions favor the undesirable torsional motion, and whistling can occur. You will rarely whistle an open E-string when starting a note with the bow already on the string, or after changing bow directions, or when playing repeated notes, because in all of these situations, each bow stroke starts from zero speed.
One way to minimize whistling is to slow the bow before it contacts the E-string while increasing bow pressure. This combination favors the Helmholtz motion over the torsional. This is not easy in practice because players tend to increase bow speed when increasing bow pressure, which is the opposite of what is required. In his Art of Violin Playing, noted 20th-century pedagogue Carl Flesch recommends “drawing the bow near the bridge” to minimize whistling. His advice works well because a good player automatically decreases her bow speed and increases her bow pressure for a sounding point closer to the bridge. Finally, any changes to the bowing conditions (tilt of hair, angle of bow to strings, and so on) to favor a quick and clean start of the transverse vibration will help.
Although one can suppress a whistling E string with bowing technique, the bowing conditions necessary to prevent whistling may not be musically desirable. And that’s why there is no foolproof solution to the whistling problem.
A version of this article first ran in the May 2012 issue of Strings. Fan Tao is an acoustics engineer, the director of research and development at D’Addario & Co., and an active member of the Violin Society of America.
Want more instrument and bow care? Try Strings’ Violin Owner’s Manual. We also offer a handy series of web guides: Care & Repair of Violins or Violas, Caring for Your Violin or Viola Bow, Care & Repair of Cellos, and Caring for Your Cello Bow.