A control device is provided which mixes and outputs two types of audio signals processed under standards different from each other; in particular, an audio signal of ASIO standard and an audio signal of WDM standard. An audio interface is connected to a computer, and an audio signal is input to the computer. A mixer module of the computer mixes an audio signal which is effect-processed by an ASIO application and an audio signal reproduced by a WDM application, outputs the mixed audio signal to the audio interface, and also outputs the mixed audio signal to the WDM application and records the sound. In each step of the process, double buffering is used to reduce sound drop-out.