The „wolf in the cello” is an acoustical phenomenon that arises from the interaction of string and body. Practically every cello is affected by the wolf, while it occurs in an individual frequency for each cello. The wolf note is characterized by strong beats in the radiated air-borne sound, reminding the howl of a wolf, which is considered to be annoying. The wolf note can be eliminated by the combination of smart materials and active systems. The development of real-time-algorithms enables the detection and the effective elimination of the wolf notes while being able to adapt itself to changing environmental conditions.