Abstract: An apparatus for generating a sound field description having a representation of sound field components, including a direction determiner for determining one or more sound directions for each time-frequency tile of a plurality of time-frequency tiles of a plurality of microphone signals; a spatial basis function evaluator for evaluating, for each time-frequency tile of the plurality of time-frequency tiles, one or more spatial basis functions using the one or more sound directions; and a sound field component calculator for calculating, for each time-frequency tile of the plurality of time-frequency tiles, one or more sound field components corresponding to the one or more spatial basis functions evaluated using the one or more sound directions and a reference signal for a corresponding time-frequency tile, the reference signal being derived from one or more microphone signals of the plurality of microphone signals.

Abstract: Disclosed is an optimizing method for regulating the operating state of a guided machine tool having a tool rotating at a certain speed and subjected to a percussion frequency during a boring action, in which the tool, subjected in addition to a force, is driven into an object of a given material.