Understanding that stuttering sound that’s the arch enemy of nearly every cellist is the first step toward eradication
By Elizabeth Marshall
A version of this article first ran in the May 2014 issue of Strings.
Ranging in severity from a small nuisance to an aggravating, exhausting, chronic problem, the pulsating, sometimes howling sound called a wolf tone can completely ruin a playing experience for a performer. Though common to many bowed stringed instruments, it’s particularly common in cellos. All cellists should take heart knowing they are not alone in their pitch woes, as it’s a common malady afflicting not only their instrument, but also those of their cello-playing colleagues. Like all matters of instrument adjustment, repair, and maintenance, a little knowledge goes a long way when taking on a wolf tone.
Before discussing remedies for the elimination of a wolf tone, it’s important to understand the underlying cause of this phenomenon. Simply, a wolf note is produced when a played tone nearly matches the natural resonating frequency of the instrument’s top and makes a pulsating, sometimes howling sound that gives the issue its name. The two mismatched sounds, from the string and from the top, generate a sympathetic overtone that collides with the original pitch and alternates between canceling and amplifying the sound. The result is an oscillating, beating sound that accompanies the affected pitch. Sometimes the sympathetic interference can be great enough to cancel out the note almost completely, generating a whistling, seemingly pitchless sound. The notes typically burdened with wolf tones tend to be somewhere in the range of D to G (open D to the fourth finger in first position), though they have been known to reside elsewhere.
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Observing the Wolf
There are several methods for resolving the issue, though they will likely require a trip to your trusted luthier. The first issue to check is whether your cello has an open seam. An open seam will exacerbate a wolf tone and in some cases, cause the pitch to move to other notes. By being sure that your seams are closed and the body of the instrument is sound, the real battle against the stuttering tone may commence.
A cello out of adjustment will prohibit a trained luthier from properly assessing the wolf tone, as the pitch and overall sound of the cello may be compromised, so the luthier’s next step is to check the fit of the bridge and soundpost. Starting with the basics of an instrument, for instance, the setup and wellness of the bridge and soundpost placement, a luthier can begin to truly examine the problem. With a clear picture of the true wolf, you and your luthier can decide which wolf-tone eliminator or suppressor will be most beneficial for your cello.
Though they come in different shapes and sizes, many wolf-tone eliminators work by using the same technology—they add weight to an instrument or string, and dampen the vibrations of the cello. Because the frequencies are quieted by the additional weight placed on the instrument, every cellist should start small. By using the lightest, least invasive implement possible, you are likely to surrender less of the total sound of the instrument.
Meet the Suppressor
Perhaps the most recognizable eliminator is the tube-shaped suppressor that fits on one string between the bridge and the tailpiece. This device is a rubber tube encased in a brass or chrome tube, held in place by a small set screw. This suppressor should reside on the string tonally lower than the string exhibiting the strongest wolf. For example, if the strongest wolf tone is found on the F# on the D string, the suppressor will likely work best on the G string. The suppressor should be moved along the length of the string, in small intervals, until the pitch of the wolf tone matches the pitch of the string’s after-length (the name for the length of string between the bridge and tailpiece) supporting the eliminator. By matching those two pitches, the wolf can be maneuvered to the semi-tones between the most-played notes on your cello. The wolf is not likely to disappear completely, but the on-string wolf eliminators can help redirect the fuzzy pitch to a more desirable location.
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Similar to the tube version of wolf eliminators is the variety that rest on the string without a screw apparatus to keep them in place. The small, brass suppressors from New Harmony Music are specifically weighted to coincide with your particular wolf tone. Designed by retired physicist David Bice, the New Harmony wolf tone suppressors are easy to install, as they simply encase the string. They should be “tuned” the same way as the original brass tube eliminators, checking to make sure the wolf tone and the string after-length match one another.
Perhaps the most definite way to manage a wolf tone through a suppressor system is to use a product that adheres directly to the source of the wolf—the body of the cello. One, the Götz Wolf Tone Suppressor is a small, rectangular weight that is centered over a set of springs. The device adheres directly to the top of the cello by using either the soft putty the company provides or lightweight, water-soluble glue, on the treble side where the wood “beats” the strongest when the wolf tone is played. The oscillations of the wolf cause the body of the cello to vibrate wildly and a luthier will test the wood on the top plate to find the spot where the beats are most pronounced. By attaching the specifically matched weight to the cello, the beats are dampened and the wolf tone is typically dramatically curtailed. If you find the eliminator to be unsightly, your luthier can flip the suppressor to the underside of the top plate, making it invisible. Though this method may sound slightly intimidating (most cellists are not keen on the idea of gluing foreign objects to their instruments!), eliminators like the Götz are harmless and impermanent when executed by a professional luthier. This type of system is usually more expensive than its on-string competitors, but the result is typically quite dramatic and positive.
It’s a common belief in the cello community that the bigger the wolf, the better the cello. This is not an entirely untrue statement, as the more powerful the resonance of the cello, the more prominent and, in some cases, startling the wolf note will be. No matter the method of wolf-tone suppression used, the bothersome tone is not likely to disappear completely. It can be managed and moved to a space between two pitches, but is in most cases a character trait of any given cello. Cellists over the years have learned to play around their wolf tones through modified bow speed and pressure, and most consider it to be an inevitability. However, with some persistence and experimentation, the wolf tone can be kept to a dull howl.
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.