An apparatus includes: a driving route calculator configured to obtain vehicle information about a vehicle and calculate a driving path of the vehicle; an object detector configured to detect an object near the vehicle or the driving path of the vehicle using one or more sensors mounted on the vehicle, and obtain object information on the object; and an acoustic signal processor configured to control a frequency and a volume of an acoustic signal based on the vehicle information and the object information, and transmit the acoustic signal to a speaker mounted on the vehicle.