An apparatus is designed for updating setting of parameters so as to control an audio signal. In the apparatus, a holding section holds current values of the parameters effective to control the audio signal. A storing section stores a plurality of scene data, each scene data has a set of setting values of the parameters. A specifying section reads out one of the scene data from the storing section and specifies a setting value of at least one parameter contained in the read scene data. A determining section determines a unit updating amount of the specified parameter for use in a manual update mode according to both of the current value of the specified parameter and the setting value of the specified parameter. An updating section includes a manual operation device operable in the manual update mode for inputting an operation amount, computes an effective updating amount for the specified parameter according to the operation amount inputted by the manual operation device and the unit updating amount determined for the specified parameter, and updates the current value of the specified parameter by the calculated effective updating amount toward the setting value of the specified parameter in response to the inputting of the operation amount by the manual operation device.