An active acoustic control system comprising: an active noise control apparatus configured for outputting a canceling sound to cancel a muffled engine sound (NZe); an active sound control apparatus configured for outputting a sound effect as a quasi-engine sound; and an operation switcher configured for switching between operation of the ANC apparatus and operation of the ASC apparatus, based on an operational range of the ANC apparatus and an operational range of the ASC apparatus which are related to at least an engine rotation frequency (fe), wherein the operation switcher is further configured for changing the operational range of the ANC apparatus and the operational range of the ASC apparatus depending on an active cylinder number (Ncy) of an engine, which can be operated in an all-cylinder mode in which all cylinders are active and in cylinder-deactivation modes in which some of the cylinders are deactivated, characterized in that the operational range of the ANC apparatus has a minimum value of the engine rotation frequency (fe) at which the operation switcher switches to operate the ANC apparatus, the minimum value being set to a quotient obtained by dividing a minimum value of noise frequencies to be controlled by the ANC apparatus, by the order, with respect to the engine rotation frequency (fe), of a chiefly generated frequency component of the muffled engine sound (Nze) depending on the active cylinder number (Ncy); and the operational range of the ANC apparatus has a maximum value of the engine rotation frequency (fe) at which the operation switcher switches to operate the ANC apparatus, the maximum value being set to a quotient obtained by dividing a maximum value of the noise frequencies to be controlled by the ANC apparatus, by said order. an active noise control apparatus configured for outputting a canceling sound to cancel a muffled engine sound (NZe); an active sound control apparatus configured for outputting a sound effect as a quasi-engine sound; and an operation switcher configured for switching between operation of the ANC apparatus and operation of the ASC apparatus, based on an operational range of the ANC apparatus and an operational range of the ASC apparatus which are related to at least an engine rotation frequency (fe), wherein the operation switcher is further configured for changing the operational range of the ANC apparatus and the operational range of the ASC apparatus depending on an active cylinder number (Ncy) of an engine, which can be operated in an all-cylinder mode in which all cylinders are active and in cylinder-deactivation modes in which some of the cylinders are deactivated, characterized in that the operational range of the ANC apparatus has a minimum value of the engine rotation frequency (fe) at which the operation switcher switches to operate the ANC apparatus, the minimum value being set to a quotient obtained by dividing a minimum value of noise frequencies to be controlled by the ANC apparatus, by the order, with respect to the engine rotation frequency (fe), of a chiefly generated frequency component of the muffled engine sound (Nze) depending on the active cylinder number (Ncy); and the operational range of the ANC apparatus has a maximum value of the engine rotation frequency (fe) at which the operation switcher switches to operate the ANC apparatus, the maximum value being set to a quotient obtained by dividing a maximum value of the noise frequencies to be controlled by the ANC apparatus, by said order.