Yes, closing the door of a room can help reduce the amount of noise that enters or exits the room. Doors, especially solid ones, act as barriers that block or absorb sound waves, preventing them from easily traveling through the door. When the door is closed, it can help create a more isolated and quieter environment within the room by reducing the transmission of sound from outside the room or from adjacent spaces.
However, it's important to note that the effectiveness of noise reduction will depend on various factors, such as the quality and thickness of the door, the presence of gaps or cracks around the door frame, and the intensity and frequency of the noise source. While closing the door can certainly help dampen the noise, it may not completely eliminate it, especially if the noise is very loud or if the door and its surroundings are not well-insulated.
For even better noise reduction, you can consider using additional soundproofing techniques such as sealing any gaps around the door, using weatherstripping, or adding acoustic panels or curtains to the room.