Loudspeaker

Voice evacuation systems (also called Voice Alarm Systems) have become popular in most countries. Voice evacuation alarms typically are not as loud as horns or bells (although generally standards require the same minimum sound pressure levels), and usually sound an alarm tone (typically a slow whoop, code-3, or chime tone, although this depends on the country and particular application) and a voice message warning that an emergency has been reported and to evacuate the building (often also directing occupants to not use elevators). Voice evacuation systems can also be used by personnel to give specific live information and/or instructions over the alarm system using a built-in microphone, which provides a distinct advantage over horns or bells. The system can be stand alone (i.e. using dedicated loudspeakers, which can also feature integrated strobe lights), or the system can accommodate public address system functionality. [Fire alarm notification appliance. Wikipedia]