In a mixer system including an editing device that edits a configuration of signal processing by designating a combination of a plurality of components and a DSP that processes audio signals in accordance with the signal processing configuration edited by the editing device, when the mixer engine does not store a predetermined enabling key, audio signal processing including a protected component in the mixer engine is disabled, and when the mixer engine stores the predetermined enabling key, the audio signal processing is enabled. Further, the editing device is permitted to edit a signal processing configuration including the protected component irrespective of storage of the enabling key in the mixer engine.