The right loudspeaker sound system is essential for effective emergency mass notification in any public place. The system must be able to deliver life-saving information and instructions “loud and clear” to everyone for the best possible outcome.
Whether it’s a public-safety matter, such as an accident, fire or terrorist incident, or a weather-related incident, such as a tornado or wildfire, sound volume and clarity are equally important. When commotion and confusion are compounded by language problems, only the highest levels of sound volume and voice clarity will shorten the time to process information and follow potentially life-saving instructions.
You can confidently specify the right equipment for your system by following these five steps:
1. Start with an on-site acoustic sound survey. The sound survey will help you determine the best locations for speakers and the sound levels you’ll need at each targeted point. You’ll want your loudspeaker to deliver sound at 6 to 10 dB above the ambient level. Six dB is the minimum; 10 is double the ambient noise level. Make sure every vendor who bids on the project has your sound measurements so they know your requirements at each point. Speaker placement needs to account for physical characteristics, such as buildings, trees and topography that can block sound waves.
2. Specify the right equipment. The human ear does not respond equally to all frequencies. Power and intelligibility are both necessary. Humans are much more sensitive to sounds in the frequency range of 400 to 6500 Hz. For best clarity and understanding, it is necessary for the harmonics of the human voice – as delivered by the speaker system – to be above 2000 Hz. Harmonic distortion should be less than 1 percent at full RMS power. The absolute minimum standard for voice clarity is that 50 percent of words be understood – a 0.5 intelligibility level – but that’s inadequate. 70 percent understandable – a 0.7 intelligibility level – is more acceptable, but a higher level is better still. Intelligibility levels above 0.8 would be much better. These are important technical details. Don’t “cheap out” with a system designed for sirens or a lesser-quality system. Make sure your system has battery back-up and that it meets military environmental standards to withstand severe outdoor weather conditions.
3. Integrate with other mass notification technologies. There is no single solution when it comes to notifying people in an emergency. Getting the same information at the same time to everyone affected is necessary to help you protect and save lives. When it comes to notifying people, you have many “targets” to consider – and all are important. A lot of moving parts must work together. Emergency responders can serve people more effectively by hearing the instructions given to the public and other responders.
4. Use pre-recorded messages – in multiple languages – to save time and avoid confusion. You can fill a huge void if your emergency mass notification system has a component that can play pre-recorded warnings and voice messages in several languages. IMLCORP’s AlertCommander pre-recorded warning tone and voice message delivery system, which works with our SoundCommander loudspeaker systems, is an example of how this technology should work. You should be able to choose from a large library of warning tones and prerecorded voice messages that cover all types of emergencies. It should be a matter of policy and procedure to determine the warning tones, messages and languages you will need. Then, using unique Alert Command software for your windows PC, you can store, edit, manipulate, group and record your own messages in multiple languages and project those files through the SoundCommander system using an included portable touch-screen, Android-based tablet.
5. Have the Ability to Access Your System from an Off-site Location. The time and conditions of any type of emergency at a public venue may require the activation of the emergency mass notification system from a cell phone, landline or off-site computer. Further, you may need to change messages for your loudspeakers and other notification platforms as events unfold. Make sure that the system you specify has multi-stage access security using passwords and other security measures. Also make sure that your policies and procedures definitively state who has access to the system and how it is to be used. Specifying and installing a system does require attention to many details, and it does require clear policies and procedures to activate the system and use it effectively to protect lives and property. But it can — and should — be done. You can learn more by reading our White Paper on sound systems for public places. Contact Us to answer your questions and arrange for a consultation.
As the designer and manufacturer of outdoor loudspeaker systems for high-clarity voice communications in all types of emergencies and for tactical operations, we have developed SoundCommander® SC360 wide-area fixed-location systems and deployable systems, including the SC1100 series and SC5600 acoustic hailing device (AHD) that can all integrate with other emergency response and mass notification technologies. Dispatchers and commanders will be able to communicate directly with people involved in any kind of emergency in real time and help responders to act more efficiently at the scene to better serve public safety needs.