The NSM provides the ability to continuously track and monitor surrounding ambient noise levels, even during announcements. This information is used to automatically adjust public address announcements to ensure they are broadcast at a predefined level above ambient noise. This ensures that the announcements can be clearly understood above ambient noise at all times. They are ideal for use in areas where ambient noise levels change constantly, such as shopping centers, sports facilities, train and bus stations, etc., and it is important to monitor ambient noise levels to ensure clear and intelligible announcements.