The coupling of electrochemical processes and ultrasound has found a larger number of applications during the past years. Especially in the field of materials science and energy technology its potential for the production of nanomaterials, improved metals, alloys and composites is noteworthy. In this paper the focus is on fundamental studies applying the electrochemical quartz crystal microbalance technique in order to improve understanding of these sonoelectrochemical processes. Three examples from the work of the authors in the area are presented: A study of the modification of the electrodeposition of Cu from chloride-based electrolytes by ultrasound, the deposition of metal/ceria composites from electrolytes low in ceria content, and the deposition of metal nanoparticles for decoration of solid oxide fuel cell anode powders. In the first two examples the electrochemical quartz crystal microbalance technique is applied in situ, whereas in the latter example it was used to study the electrochemistry of the systems involved.