Look for wolf notes on a violin at B flat to C, on a viola at E to F sharp, and on a cello at E to F sharp. Basses depend on size. Wolf notes are caused by excess tension or by a break-down in acceptable pattern of vibration. To remedy this problem, try the following:

1. Check that no part of the instrument has become unglued.

2. Change the string to a thinner one with less inertia.

3. Alter the sympathetic vibration of the strings, possibly by lengthening the tail-gut to give a slightly shorter overall string length.

4. Adjust the bridge or soundpost or fit a heavier tail-piece.

5. Fit a wolf note eliminator, e.g. Super-Sensitive Wolf-Be-Gone. Slip the rubber insert and the metal collar over the string between the tail-piece and the bridge, and then screw over the rubber insert. When moving the eliminator nearer of further from the bridge, the wolf note can be effectively altered in pitch and placed on a quarter tone or a less vital note. It will also reduce the wolfing to some degree. The third string is a potent wolfer on the cello: if the suppressor doesn't make any difference, the chances are you haven't tightened it enough. Remember to check the rubber feet from time to time to make sure they have not hardened and are not harming the wood.