August 2018 Newsletter: The Sound of Security

Security concerns are ever-present in today’s world, and novel solutions must be developed to deal with potential information leaks. Sound masking systems are increasingly enlisted, not only to provide improved worker comfort and productivity in open office areas, but also to increase privacy and prevent eavesdropping in highly confidential industries. As information becomes more valuable, the motivation to steal it becomes greater. There are 6,500 incidents of industrial espionage each year in the United States with an average economic impact of $1.25 million per incident, costing Fortune 1000 companies over $53 billion. Read on to learn more about how sound masking can be an effective tool in the security kit of parts.

How are they listening?

For typical corporate offices, sound masking systems can be used in hallways outside of meeting rooms to provide privacy for conversations therein. However, industries with highly-confidential information, such as pharmaceutical and government, have the potential to leak extremely valuable or even potentially dangerous information. Eavesdropping has taken on a certain 007-quality due to laser microphones, fiber-optic bugs, and vibration detection systems which can interpret human speech.

Structure-borne vibration through windows, pipes, HVAC ducts, doors, floors, walls, and ceilings are all potential opportunities for a security breach. Vibration-monitoring “bugs” make use of strain gauges, piezoelectric elements, or even tapping into a ceiling speaker and using it as a microphone. Laser and parabolic microphones use the vibration of a window to eavesdrop on a conversation by calculating the minute delay of signal reflections.  Some of these bugs can run independently of a power source and can be turned on remotely resulting in a nearly undetectable device.


How do we STOP them from listening?

We may never stop them from listening, but we can make our signal as unintelligible as possible. In a similar manner to addressing acoustic privacy on a standard project, we can focus on reducing the signal-to-noise ratio.

One method of reducing intelligibility is to introduce random, non-repeating noise designed to mask human speech frequencies. To accomplish this, each structural element must be excited with a sound masking transducer – a surface-mounted device designed to introduce vibrations to the element. The signal varies from surface to surface to avoid detection, and ideally the masking signal should turned off or reduced when there is no speech happening within the space.

The masking signal itself becomes more complex for higher levels of security and often a three-layer signal is used. The first layer is a standard sound masking noise signal designed to cover the entire speech spectrum. The second layer is music, tuned to a lower amplitude than the first layer. The third layer is “voice babble” – incoherent human speech. There is random variance in the levels of each of these signals. All of this is done to protect the “fourth layer”, or the private speech occurring within the space, which should be totally incoherent when combined with all of the other measures taken to prevent eavesdropping.

While James Bond may not be real, there is certainly no shortage of prying eyes and ears. Protection of confidential information should be one of the main goals of any company.

September 2018 Newsletter: Let Freedom Ring!
July 2018 Newsletter: Step to the Beat