The adaptive regulation is an important issue with a lot of potential for applications in active suspension, active vibration control, disc drives control and active noise control. One of the basic problems from the " control system " point of view is the rejection of multiple unknown and time varying narrow band disturbances without using an additional transducer for getting information upon the disturbances. An adaptive feedback approach has to be considered for this problem. Industry needs a state of the art in the field based on a solid experimental verification. The paper presents a benchmark problem for suppression of multiple unknown and/or time-varying vibrations and an associated active vibration control system using an inertial actuator on which the experimental verifications have been done. The benchmark has three levels of difficulty and the associated control performance specifications are presented 1. An extensive comparison of the results obtained by various approaches will be presented 2 .