In-car systems such as car-navigation systems and car-audio systems are requisite to provide the driver and passengers with a comfortable driving experience. The driver generally needs to hear announcements reproduced by the car-navigation system, whereas the passengers only want to hear the music reproduced by car audio system. Since these signals interfere, the separation of these signals is crucial to achieve a comfortable drive for both the driver and passengers. To separate the sound signals for the driver (car-navigation announcements) and those for the passengers (music) at the driver's seat, we propose a method based on active noise control (ANC) with head-enclosing loudspeakers. The head-enclosing loudspeakers are mounted around the driver's seat so that they suppress the music from the car audio system. They emit the announcement and a signal to suppress the music as noise. The signal emitted by the head-enclosing loudspeakers does not mask the music at the seat positions of passengers because the energy of the emitted sound is lower than that of the music. Since the music which should be suppressed is the known signal, the proposed method may efficiently suppress it. The proposed method does not require the adaptive filters generally used for ANC. Subjective and objective experiments on speech-recognition accuracy were carried out to verify the effectiveness of the proposed method. The evaluation results show that the music for passengers is suppressed and announcements are enhanced at the driver's seat.