A sound-modulating device used in a confined space is provided. The sound-modulating device includes an event detector and an audio module in communication with each other. The event detector detects an event and generates a trigger signal in response to the detected event. The audio module plays a music segment in response to the trigger signal. The frequencies of the music segment range from 20 Hz to 20000 Hz. The intensities of the music segment are smaller than or equal to 75 dB.

A sound-modulating device used in a confined space is provided. The sound-modulating device includes an event detector and an audio module in communication with each other. The event detector detects an event and generates a trigger signal in response to the detected event. The audio module plays a music segment in response to the trigger signal. The frequencies of the music segment range from 20 Hz to 20000 Hz. The intensities of the music segment are smaller than or equal to 75 dB.