Page 26 - Campus Security Today, September/October 2023

CAMPUS AUDIO “” Audio can detect voices, noises, or other sounds that are not within direct view of a video camera. Those sounds can be analyzed by a security team, and action can be taken before the individual gets to the school doors. Adding audio also means that a security officer and the person in front of the camera at the intercom can interact, even when that individual is at outer perimeters—which, if they have ill intent, is where you want them to stay until your security team can arrive on scene. That data, which goes beyond video surveillance images, can be shared between security, police, emergency services and more. Your secu- rity team is now providing first responders with actionable data for a more effective response and a strategy to mitigate future incidents. THE IMPORTANCE OF CLEAR AUDIO It’s exciting to witness the rapid growth of audio technology’s im- portance in security operations that mitigate security threats and enable faster response on K–12 and college campuses. Yet are all those devices delivering crystal-clear audio? Is the need for users to be clearly heard and understood being met, every time? Strong, crystal-clear voice communications are possible in any environment, but it requires the right combination of hard- ware, software, and mechanics. THE RIGHT HARDWARE An intercom’s hardware combination of amplifier, speaker, and micro- phone must be robust enough to withstand extreme environments and deliver audio loud enough to overcome all background noise. Any outdoor communication device should incorporate a digital MEMS microphone, allowing audio to be consistently translated into 1’s and 0’s, regardless of extreme temperatures or moisture. A Class- D, 10W amplifier delivers more than 95dB, louder than a semitruck or subway train. And with an amplifier that powerful, a matching 10W speaker is crucial to avoid distortion at high volumes. THE RIGHT SOFTWARE With IP technology, audio processing software can be deployed directly in the edge device to create the best intelligibility. Noise Reduction technology removes background noise so that the operator can clearly hear the caller. Native, Onboard Acoustic Echo Cancellation prevents feedback and enables full Open Duplex communication, where both people can talk at the same time, and be understood. Devices should also intelligently adjust to the environment; Automatic Gain Control will take a voice that is too loud or too weak and level it out to an undistorted and clear signal. Automatic Volume Control will raise the speaker volume, so it is always loud enough to be heard. THE RIGHT MECHANICS The mechanics of an intercom are important, as well. A traditional, EMERGENCY STANCHIONS CAN PROVIDE A VISUAL AND AUDIO INDICATOR TO HELP SECURITY TEAMS TO IDENTIFY VISITORS AND VENDORS OUTSIDE OF A SCHOOL’S ENTRANCES AND EXIT POINTS. vandal-resistant intercom speaker design uses two overlapping stainless-steel plates, which trap the sound waves between them and create distortion, especially at higher volumes. Instead, the speaker grill should incorporate an anechoic, circular design where there’s no reflection of sound waves as they pass through the sta- tion’s faceplate. The result is crystal-clear audio, even at the loud- est volume. Unfortunately, loud volume creates significant vibra- tion, so the speaker grill should be die-cast into a rigid aluminum frame and the microphone surrounded by a dampening material, to protect against the transfer of any sound vibrations. All these mechanical elements work together to produce strong, distortion- free, intelligible voice audio. Only this combination of hardware, software, and mechan- ics will ensure clear audio and clear communications. When you understand how intelligible audio is achieved, then you can find the communications solution that will reliably allow you to hear, be heard, and be understood, every time. Every K–12 and campus school security team faces increas- ingly complex threat environments, especially at their perimeters. Audio solutions via intercoms and IP speakers are the solution to providing intelligence and communications and to securing those perimeters. 26