Wolf Terminator

Wolf Note Eliminator for Cello

The Wolf Terminator is our answer to the problem of controlling wolf notes on the cello.
Table of Contents
The Cello Wolf Note (Just Below F#3 on this instrument)

The Wolf Terminator is our answer to the problem of controlling wolf notes on the cello. Effectively addressing all of the shortcomings of the existing methods and devices, the Wolf Terminator (patented) is both technically advanced and easy to adjust. The details of the device’s construction and the explanation of its features will, we hope, convince you that our method of controlling the wolf note is truly superior to other devices on the market.

By making the Wolf Terminator as light as possible, we avoid much of the dampening of tone associated with the “brute force” type of wolf eliminator. This is done in two ways. First, the body is made as light as possible: the majority of the weight is in the resonator portion of the device. The resonators must have a small amount of weight in order to be effective because the suppression, at the wolf note frequency, is accomplished by the weights vibrating in the opposite phase to the vibrating top. This weight is kept to the minimum required to effectively counteract the wolf note. And second, because the Wolf Terminator can be attached to different parts of the top, the damping from the overall weight of the suppressor can be minimized and the actual amount of suppression can be tailored exactly to the amount the player wants.

The Wolf Terminator In A Typical Installation

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The Wolf Terminator may be installed in different locations on the cello, depending upon cosmetic considerations and upon the severity of the wolf note.. A typical installation would be along the left edge of the tailpiece on the C string side (seen in the photo).

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With our updated Wolf Terminator, the WTC-3, the wolf note can be eliminated even when the mounting position is out of sight beneath the tailpiece.

Removable adhesive “aka museum putty” is used to attach the Wolf Terminator to the top of the cello. This material allows repeated mounting and remounting of the device without damaging the finish.

The Wolf Terminator is completely and easily adjusted to the precise frequency of the wolf note. An adjusting screw allows the player to adjust the device to any note between D3 and G3. This encompasses the wolf note range of the vast majority of cellos and allows the player to confidently purchase without worrying whether or not the device will tune to the wolf note frequency of his instrument. Changing strings will not affect the frequency adjustment of the Wolf Terminator nor will the Wolf Terminator affect the use of mutes. Because the wolf note frequency may (probably!?) change with the seasons or with variations in temperature, it is important to be able to quickly and confidently adjust for these changes. Cello players will appreciate how quickly and easily this is done.

The Tuning Range Is D3 To G3 And Is Easily Adjusted

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A single adjusting screw adjusts both resonator blades at the same time. The supplied allen wrench allows precise adjustment.

Dual Resonator System

The heart of the Wolf Terminator lies in the dual resonator system in which two vibrating resonators are tuned to the wolf note. There are small weights flexibly attached to each resonator, allowing the length of the device to be shortened while still maintaining the required frequency range. 

A further refinement in the dual resonator system is precise frequency separation between the two resonators. As noted on the page on wolf notes, the wolf note is composed of two separate notes beating together at the pulse or beat frequency. The dual resonators in the Wolf Terminator span the separation between the two notes which comprise the wolf and, most importantly, anchors the wolf note and prevents it from moving away from the resonant frequency you are attempting to suppress.

The Vibrating Resonators

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Each resonator is carefully tuned so that a precise frequency separation between the two is maintained throughout the adjustable frequency range.

As mentioned earlier, the actual amount of suppression can be decreased by moving the Wolf Terminator to less resonant areas of the top. Because of its efficiency, the wolf note can be suppressed even when the device is moved away from the most sensitive top areas, giving the player the flexibility to suppress the wolf just enough to be controlled but not so much that the overall tone suffers. On the other hand, on cellos with really pronounced wolfs, the Wolf Terminator will suppress the wolf note even when played on the C string. In our development work, we have not found any other wolf eliminator which can make that claim. Of course, it’s not likely you will be playing in the wolf note area on the C string but it’s comforting to know that the capability is there.

The following two frequency analyzer curves show graphically: (1) how the Main Body Resonance (MBR) can be reduced in various amounts so that the wolf note can be eliminated, and (2) how the note at the wolf note frequency appears when the Wolf Terminator controls the wolf.

(Fig. 3) Wolf Terminator Installed On Cello


In this view of the frequency analyzer screen, the main body resonance curve (MBR)/ wolf note is displayed together with displays showing several levels of suppression when the Wolf Terminator is installed.  Levels 1,2 and 3 represent light to moderate levels of suppression. All levels show suppression within a single semitone while having little effect on the volume of the instrument beyond the wolf note. Depending upon placement on the cello top, suppression can easily be varied from very light to very heavy.

(Fig. 4) Wolf Terminator Installed On Cello: Note Plays Normally


When the Wolf Terminator is adjusted to provide sufficient suppression of the Main Body Resonance (the wolf note frequency)  a note played at the wolf note frequency can be played without any trace of a wolf. The cello used in this display is the same as the one used on the Resources page under the heading, The Plysics of the Wolf Note. Note: all frequency analyzer displays shown on this website are of the same cello and tested under identical conditions.

The Wolf Terminator In Action

In this video, a passage which includes the wolf note is played. The Wolf Terminator is installed and adjusted in several stages until the wolf note is eliminated. The passage, without the wolf note, is again played. In addition to hearing the gradual elimination of the wolf note, you will observe the ease of installation and the simplicity and speed of adjustment.


Video #1: Installation and adjustment



Eliminating the Wolf Note From the C String

Wolf notes on the C string are typically much more severe than on the G (and D) string and are very difficult or impossible to eliminate with conventional wolf eliminators. Because the Wolf Terminator is so efficient in  suppressing wolf notes and because notes in the wolf note range are rarely played on the C string, most players will elect to suppress the wolf note primarily on the G (and D) string. This installation strategy eliminates the wolf note completely, requires less suppression, and has little or no effect on the overall tone.


 Video #2: Removing the difficult C string wolf note

We hope we’ve made a convincing and enthusiastic argument for the Wolf Terminator and we invite your questions or comments! The price of the Wolf Terminator is $109.50 and if you would like to order online, ground shipping (USPS Priority Mail) anywhere in the United States is included. 

The Robust Solution To Wolf Note Suppression