High-quality sound systems can be implemented over a virtually limitless, multi-zone area

Audio Combines Communication And Security

High-quality sound systems can be implemented over a virtually limitless, multi-zone area

Over the past two decades, many widely known incidents have occurred that have caused the loss of life. Emergency situations, ranging from the 9/11 attacks to fires to public stampedes at sports and religious gatherings, have caused various agencies to begin to analyze the weaknesses of all types of communications systems used in venues and transportation hubs worldwide.

Historically, such systems were focused primarily on fire alarm communications, but in relatively short order, the requirements have expanded into all areas of life safety and emergency communications.

Increasingly, these systems must comply with local, national or international codes and standards. In the United States, we typically see National Fire Alarm and Signaling code NFPA 72, and internationally we are beginning to see countryharmonized standards like EN54. Before the harmonized agreement, each European country had its own equipment standards. NFPA 72 has been revised many times, and in 2007 a definition for mass notification systems (MNS) was added. The Emergency Voice Alarm Communication System (EVACS) standard was written in 1985, but intelligible voice sound—not the old whistles, bells and tone signalling—was not included until 1999.

In regard to intelligibility, arguments have raged from all factions in the alarm and communications industry ever since NFPA mentioned the word. Intelligibility is not easy to quantify; it is a science requiring complex measurements.

However, if people in an emergency cannot accurately understand the messaging during a crisis, how are they, en masse, going to save themselves?

To improve public safety, NFPA is attempting to provide guidance through voice communication systems.

Achieving Intelligibility

It is the responsibility of the authority having jurisdiction (AHJ) to determine which spaces or areas require intelligible sound. Typically, AHJs don’t require intelligible voice communications in closets, mechanical rooms, kitchens and the like. However, it is unreasonable to expect the AHJ, typically a fire marshal, to understand the complexity of acoustical testing and interpretation of data required to determine if a system provides a good speech transmission index (STI) or a poor one. It requires an individual with the proper academic background and audio experience to measure and provide the STI data and the interpretation of the results.

If a region adopts NFPA codes, the AHJ is the person who determines if the installation, performance, reporting and supervision of the system meet all the required minimum performance specifications. The AHJ must certify the results in order for the building to receive a certificate of occupancy.

The EU standard EN54—which is not a law—is a product-standard requirement. EN54-16 permits the use of a voice alarm system for non-fire alarm purposes. This allows the system to provide messaging in a wide range of emergency events, such as a bomb threat.

EN54-24 details how a loudspeaker must be tested to verify the manufacturer’s specifications, including sensitivity, power handling, frequency response and environmental durability. EN54-24 also includes details regarding loudspeakers that must be operated with their dedicated or included active electronics.

Sound systems that are used to improve transportation security have the ability to improve the protection of people and property. These versatile and powerful systems can reduce the loss of life associated with risks such as natural, technological and man-made disasters. In addition, many of these systems can double their usefulness by providing recorded entertainment when they are not required to be a link in emergency communications.

Excellent sound reproduction is often distributed throughout sports venues, office buildings, theme parks, entertainment venues, shopping malls and waterfront gathering places. In the transportation sector, we see these specialized, high-intelligibility loudspeakers used in airports, train stations, rail hubs, highway inspection areas and marine applications such as ports, ferry terminals and aboard ships.

With the adoption of IP networks, typically via fiber-optical infrastructures, advanced, bidirectional audio/video communication systems can be implemented that are fully integrated with multiple points of control. No longer is it necessary to be stuck in a central equipment room to control vast systems.

High-quality audio and video can be implemented over a virtually limitless, multi-zone area. Networking allows the system to be linked over small or vast areas with high redundancy, high reliability and freedom from any interference.

Global Examples

Sound projection patterns from loudspeakers may be actively or passively controlled with a precision that would have been hard to imagine just a few years ago. Let us look at some of the ways that loudspeakers are used to protect passengers, workers and property against security threats, while providing communications for day-to-day use.

  • In Minneapolis, high-directivity, multiway horn loudspeakers are concealed within attractive decorative housings to provide clear announcements as well as emergency communications for a typically reverberant airport atrium.
  • At London Luton Airport in the United Kingdom, a complex multipoint control, multi-zone system delivers both paging and life safety. It ensures the smooth operation of the airport for approximately 10 million passengers annually while providing for their safety should the need arise. Loudspeakers are zoned and distributed throughout the facility, from its cathedralsized shopping malls to the long walkways to the gates. In each zone, the loudspeakers have been carefully selected for their power, coverage and ability to deliver high-intelligibility voice to every public area.
  • In Orlando, the Orange County Convention Center has installed both fire alarm and public address loudspeakers. In the event of an emergency, the fire alarm enunciators work first with automatic messaging. The message is then repeated on the public address system, which is far more intelligible.
  • In Venice, Italy, an audio solution has been devised to keep the whole city moving. Its tidal waterways on a daily basis re-map the routes accessible by waterborne taxis, buses and service vessels and, on what is usually dry land, by pedestrians. To provide advance information of water levels to the city, loudspeakers are located in 15 bell towers in central Venice and in 15 other locations on outlying islands. These loudspeakers play musical tones, which are now familiar to residents, and inform them of tidal levels so that they can plan to use routes that will be accessible. Venice was a custom project for the city planners, system designers, installers and the loudspeaker manufacturer, but it remains a great example of how well-implemented audio can solve a problem for an entire city.
  • In Seattle, train platforms use powerful weather-resistant fiberglass loudspeakers that have been coated to make them graffiti resistant. Although railway stations are wellknown as highly reverberant spaces, intelligibility can be maintained by using multiple close-proximity loudspeakers with well-controlled coverage, directing the sound to the people and avoiding highly reflective hard surfaces.
  • At Biga/Canakkale in the northeast coast of Turkey, IÇDAS port has two piers and a wharf with a total in-port berthing capacity of up to 20 vessels at the same time. Controlling ship movements is critical and complex, and the sea port is acoustically covered by a combined shore-to-ship control and safety warning system. Pole-mounted, high-directivity, weather-resistant loudspeakers provide the high sound levels needed with uncompromised intelligibility, enabling ship movements in the port to be controlled by verbal commands.
  • In Vancouver, British Columbia, an auto/truck ferry terminal loading area is acoustically covered with a very high-power voice loudspeaker system to provide instructions to vehicles—even if their engines are idling and their windows are closed.
  • At the Capitol in Washington, D.C., a roof-mounted public address perimeter system is installed that inherently has the control and power to be used for evacuation if required. The system provides intelligible voice well beyond a 1,000- foot perimeter.
  • Denmark, which has a relatively small population of 6 million, has installed a giant emergency management system. Nearly every person across the country is within earshot of the system’s acoustical coverage and messaging. The system was codeveloped by a partnership between American and Danish firms. Ten thousand sites throughout the populated areas of the country ensure even sound coverage.

It may be that the Danes are showing the direction for the future of large-area wide-acoustical security systems. These systems, in conjunction with digital signage, video surveillance, network control, cellphone messaging and intelligent analytics, can help in the battle to minimize security risks.

This article originally appeared in the Security Products Magazine - July 2012 issue of Security Today.


  • Live From ISC West: Day 2 Recap

    If it’s even possible, Day 2 of ISC West in Las Vegas, Nevada, was even busier than the first. Remember to keep tabs on our Live From ISC West page for news and updates from the show floor at the Venetian, because there’s more news coming out than anyone could be expected to keep track of. Our Live From sponsors—NAPCO Security, Alibi Security, Vistacom, RGB Spectrum, and DoorKing—kept the momentum from Day 1 going with packed booths, happy hours, giveaways, product demonstrations, and more. Read Now

    • Industry Events
    • ISC West
  • Visiting Sin City

    I’m a recovering alcoholic, ten years sober this June. I almost wrote “recovered alcoholic,” because it’s a problem I’ve long since put to bed in every practical sense. But anyone who’s dealt with addiction knows that that part of your brain never goes away. You just learn to tell the difference between that insidious voice in your head and your actual internal monologue, and you get better at telling the other guy to shut up. Read Now

  • On My Way Out the Door

    To answer that one question I always get, at every booth visit, I have seen amazing product technology, solutions and above all else, the people that make it all work. Read Now

    • Industry Events
    • ISC West
  • Return to Form

    My first security trade show was in 2021. At the time, I was awed by the sheer magnitude of the event and the spectacle of products on display. But this was the first major trade show coming out of the pandemic, and the only commentary I heard was how low the attendance was. Two representatives from one booth even spent the last morning playing catch in the aisle with their giveaway stress balls. Read Now

    • Industry Events
    • ISC West

Featured Cybersecurity

New Products

  • PDK IO Access Control Software

    PDK.IO Access Control Software

    ProdataKey now allows for "custom fields" within the interface of its pdk.io software. Custom fields increase PDK's solutions' overall functionality by allowing administrators to include a wide range of pertinent data associated with each user. 3

  • Tyco Kantech EntraPass security management software

    Tyco Kantech EntraPass security management software

    Johnson Controls, the global leader in smart, healthy and sustainable buildings, and architect of the Open Blue digital connected platforms, has released the newest version of the Tyco Kantech EntraPass security management software. 3

  • Unique Oversized ID Card Printer

    Unique Oversized ID Card Printer

    Idesco Corp. is announcing its card printer – the XCR100 2.0 printer- that allows customers to personalize oversized ID cards on demand. The printer is ideal for assisting healthcare organizations find the right badging solution. As healthcare facilities continue to combat the spread of COVID-19, issuing oversized ID cards has helped identify staff clearly while adding an extra layer of security. The XCR100 2.0 printer is the only dye-sublimation printer on the market that can personalize CR100 cards (3.88" x 2.63"). The cards that are 42% larger than the standard credit card size. The printer can produce up to 180 full cards per hour in color, and up to 1,400 cards per hour in monochrome. An optional flipper is available to print dual-sided badges in one pass. Contactless encoding comes as an option to help healthcare facilities produce secure access badges on demand and the card printer features a 2-year warranty. 3