What is a Wolf?
A wolf is an undesirable wavering of pitch encountered mainly in cellos. However, it has been known to occur on violas, and very rarely on violins. A wolf is immediately noticeable to most musical ears as a wavering or uneven tone quality. In some cases, the player can actually feel the wolf in his/her finger. The wolf usually occurs on the E, F, or F# on the C, G, and/or D string(s). It is virtually impossible to play evenly when a wolf is present on an instrument. (How terrible is it to play the Shostakovich Cello Sonata Op. 40 with a wolf on every stinking F#?)
What Causes a Wolf?
Although I am not sure of the exact cause, I know that most cellos have an imperfect overtone quality in them that affects only the notes mentioned in the above paragraph. The physics behind a wolf are probably complicated, but it has to do with the amount of tension in the string and how the body of the cello responds to those certain frequencies.
How Can I Correct This?
The resolution is simple: Buy a Wolf Eliminator. They can be found at most music stores for about 12 dollars, and probably slightly cheaper online. They come in different weights, with extremely bad wolfs requiring heavier eliminators. Common Wolf Eliminators look like a little brass tube with a screw and a rubber part. Other versions include a button type one.
How Do I Use an Eliminator?
Separate the eliminator into its parts. If youre using the button type one, just screw it onto the offending string. If youre using the more common brass tube, place the rubber on the string, and slide the brass tube over the rubber part with the crack in the rubber lining up with the hole in the tube. Insert the screw into the hole, tightening it (make sure its tight enough to stay on, but loose enough so that you can move it around). Now its time to experiment. Every cello is different and every Wolf is different. The Eliminator should always be placed between the bridge and tailpiece of the instrument, but the exact location and in which direction the screw points depends on the instrument. Once youve found the location where the Wolf is gone (or least noticeable) tighten the screw, and make sure it wont buzz when you play! In general, if you play the string between the eliminator and tailpiece, the sounding note should match the note of the string.
