A device and a method is proposed whereupon the device for processing a packing material using ultrasound comprises the following elements: at least one sonotrode (10), at least one anvil (12), whereupon a gap is constructed between sonotrode (10) and anvil (12) through which the packing material can be passed for the purpose of ultrasonically sealing a packing material, at least one adjustment means (50) that adjusts the gap (s) between sonotrode (10) and anvil (12), at least one generator (70) that changes an input voltage into an output voltage, which a converter (74) transforms into mechanical oscillations in order to generate ultrasonic oscillations on the sonotrode (10), whereupon a regulation device and/or control device (78) is arranged to regulate or control the gap (s) between sonotrode (10) and anvil (12) depending on at least one electric variable (P,E,R) that acts on the sonotrode (10).