The present invention relates to a device for the ultrasonic processing of materials, which has an ultrasonic processing system, which comprises: an ultrasound generator, a converter (12), a sonotrode (16), and a counter tool (18); wherein the sonotrode (16) and/or the counter tool (18) has a substantially cylindrical sealing surface having at least one elevation (45) and can be rotated such that, during the processing, the elevation (45) rotates about the axis of rotation and comes in contact with the material web (20) during a sealing time, wherein a control apparatus (24) is provided for the ultrasound generator, to which control apparatus a feedback variable from the ultrasound processing system is fed and which control apparatus determines a manipulated variable therefrom and feeds said manipulated variable to the ultrasound generator, wherein a process variable from the processing process is determined and is linked to the manipulated variable determined by the control apparatus (24) before the feeding to the ultrasound generator. In order to provide an improved device for the ultrasonic processing of materials having an ultrasonic processing system, a trigger apparatus (44) is provided, which determines the position of the elevation (45) and is designed to permit or prevent the linking of the process variable to the manipulated variable in accordance with the position determination.