Audio Monitoring: A Sound Security Strategy

March 11, 2021
Audio monitoring devices have been gaining in popularity, and new COVID-based use-cases are driving further adoption
This article originally appeared in the March 2021 issue of Security Business magazine. When sharing, don’t forget to mention @SecBusinessMag on Twitter and Security Business magazine on LinkedIn.

COVID-19 seems to have shifted all aspects of life and business, and the security industry is no exception. Health screening, occupancy tracking and mask-wearing compliance have become key priorities for customers vitally concerned with improving the safety of business spaces.

As social distancing has become the new norm, identifying ways to safely interact and communicate has also been critical for end-users; thus, touchless and hands-free solutions have boomed across the video and access control segments. While these often publicized use-cases and technologies have become more common, another technology seeing a rise in demand for the same reasons is audio.

Though microphones have been deployed in security applications – such as in law enforcement interview rooms – for decades, audio monitoring solutions have traditionally been overshadowed by surveillance cameras. Audio monitoring technology comprises numerous solutions beyond intercoms for entry control and speakers for mass notification; however, a lack of clarity on the rules and regulations regarding audio deployment has created a barrier to adoption for many of these solutions. What has changed?

First, people are much more comfortable using audio technology. The use of voice assistants, such as Siri and Alexa, has been a key catalyst, as they enhance and simplify user experience. Likewise, more customers today realize the utility of integrating audio into their end-to-end surveillance solutions and IoT ecosystems for critical situational awareness.

The normalization of audio technology in and outside of the security industry has also spurred innovation within the audio world. As it relates to security, new capabilities in audio technology, such as audio analytics, have also driven demand – in fact, 18 percent of integrators added audio detection to their portfolio of solutions, according to the 2020 Security Business State of the Industry Report (access it at

Other audio benefits such as expanded evidence capture, faster threat detection, greater business intelligence, and secondary source alarm verification are driving purchase orders for audio devices across the channel – and now COVID-related use cases are driving further adoption.

Vertical Markets 

Whatever application benefits from video capture would likely also benefit from audio capture. By deploying audio and video recording technology together, integrators can ensure customers will not only be able to view a crisp image, but also capture clear sounds for optimal scene analysis, incident reporting and audio recordings – all of which is often used as evidence for lawsuits.

Moreover, external microphones offer integrators ample installation flexibility. If an audio device is untethered from a video capture device, installers can place that microphone in a location that maximizes sound pickup. Opting for an external microphone – as opposed to a built-in microphone in a surveillance camera – also enables integrators to choose a best-of-breed solution, designed by manufacturers who specialize in audio to maximize performance.

While audio surveillance technology is useful in every industry, the two seeing particular growth are the retail and healthcare verticals.

Retail: The public health and safety measures implemented because of the COVID-19 pandemic have elevated the importance of customer and employee safety. Audio monitoring solutions are ensuring businesses can protect both parties – particularly in retail environments, such as supermarkets, hardware stores and local small businesses.

A security solution that uses video, artificial intelligence-enabled analytics and two-way audio devices, for instance, enables store owners to simultaneously monitor social distancing and mask-wearing efforts and play pre-recorded messages to remind customers of a store’s social distancing policies. Hands-free speakers installed at store entrances, above store aisles, and above point of sale terminals can broadcast reminders to customers to stay six feet apart.

Outside of pandemic scenarios, audio solutions also aid in employee training and performance, as they give store operators insight into customer interactions. When installed alongside video surveillance technologies, microphones can also offer additional information to better inform incident reports, in the case of in-store employee or customer conflicts. Having an audio record of what transpired eliminates “he said, she said” arguments.

Healthcare: Audio monitoring solutions are seeing broader adoption in the healthcare industry as well. Two-way, hands-free audio devices with talk/listen capabilities simplify interactions between medical personnel and patients who have contracted an infectious disease. This enables nurses to communicate with patients without needing to don personal protective equipment (PPE) – saving valuable time and also limiting medical staff’s exposure to patients with the virus. 

These same devices also enable nursing staff to monitor sounds within a patient’s room, such as heavy breathing or coughing, and spaces such as waiting rooms and entryways, where frayed nerves may manifest as verbal or physical aggression. Microphones with audio analytics, in particular, have proven indispensable in efforts to alert hospital security and administrative personnel to combative or threatening behavior, before either can escalate into incidents of violence.

6 Keys to Effective Installation

As more customers opt to deploy audio in overall security solutions, there are several considerations that integrators should keep in mind when implementing it. While adding audio to existing surveillance systems is easier than one might think, keep these five practical steps in mind to simplify the installation:

1. Define audio needs. Is the customer looking to only capture audio from a surveilled space, or do security personnel in a remote command center need the ability to communicate with individuals on the ground? These are important questions to ask, because it will determine whether the system requires a simplex microphone, where audio is sent in one direction; a half-duplex microphone, where audio is sent in both directions, one at a time; or a full duplex microphone, where audio is sent in both directions, at the same time.

2. Determine line level or mic level. Select a microphone with an output level that matches the camera’s input level. Line level microphones are the most popular options, as they amplify the audio signal, feature reduced gain for lower ambient noise, and deliver better sound clarity. Mic level outputs, however, are often in the range of ten-thousandths of a volt, whereas line level output is about one volt.

3. Consider form factor and potential issues. Think about where the microphone will be installed, as each use-case may pose issues that contribute to the effectiveness of the solution. For example, if the device will be placed on a ceiling, the integrator should consider whether the ceiling is standard height, or if it is a high ceiling that requires the microphone element to hang closer to the ground. Consider whether the location of the microphone be vulnerable to tampering and background noise as well. One size does not fit all.  

4. Define power, audio playback and VMS source. Line level output microphones require a power source. Consider using an audio base station, which powers the microphone and provides playback features, as well as the ability to interface with video surveillance cameras and recording devices. Also ensure the video management software the customer uses indeed supports the desired audio functionality (for example, bi-directional audio) by tailoring the audio setting within the VMS.

5. Plan the audio configuration. The most common configuration is a simple plug-and-play setup, which involves running the microphone cabling alongside camera cables and selecting the correct audio settings on the camera itself – such as adjusting the bitrate, gain, etc. Opting for digital microphones, which connect directly to an Ethernet port requires locating the device name and IP address, setting up a username/password online, and selecting “live view” and other audio settings using that interface. Connecting a microphone directly to a DVR or NVR requires using a 12Vdc, then selecting the correct audio settings on the storage device.

6. Encourage the end-user to deploy signage. U.S. law permits audio monitoring as long as there is no expectation of privacy. A simple way to guarantee this is by installing clearly visible signage that says, “Audio Monitoring on These Premises.”

Richard Brent is CEO of Louroe Electronics. Request more info about the company at