July 2019 Newsletter: Beam me up Scotty

Beamforming microphone arrays are recently available in the AV industry, but beamforming technology has been around since the earliest days of sonar to track enemy submarines. What do U-boats have in common with audio quality in conference rooms? Read on to learn more about beamforming and why you may see this technology at your next meeting.

Beamforming is a technology responsible for such disparate innovations as radio astronomy, ultrasonic imaging for biomedicine, detection of underground petroleum reservoirs, and monitoring of foreign submarines. Thanks to recent advances in digital technology and clever engineering, this technology has also made huge strides into the professional AV industry as a dynamically directional microphone solution. Beamforming microphone arrays are used to track voices in a room and remove background noise. Thus, they provide a much higher signal-to-noise ratio when compared to conventional boundary microphones, dramatically improving the audio quality and user experience. Such a powerful technology has massive potential for fundamentally changing the contemporary approach to recording and transmitting spoken word.

As with many modern technological advancements, the road to the development of beamforming microphones began in the military industry. Hydrophones, or underwater microphones, were among the first platforms to utilize this concept in the form of sonar. Early hydrophone arrays were used to detect submarines, ships, and mines as early as the 1930’s. Limitations in the analog technologies of the day dictated a rather simple design. This initial implementation of beamforming was best suited to the underwater environment as soundwaves in the water are more “behaved” and predictable when compared to the open-air environment.

By the 1980’s, Digital Signal Processors (DSP) had been developed which allowed for complex algorithms to be used in conjunction with microphone arrays. With this increased level of capability, the concept was taken out of the water and into the air. Beamforming microphone arrays were developed to track the direction of firearms, rockets, artillery, vehicles, and for surveillance purposes.

Beamforming microphones are arranged in an array such that signals at particular angles receive constructive interference while others experience destructive interference. In this manner, the signal from a specified direction can be selected as a “target” while the signals received from other directions are canceled out. Within the last year, beamforming microphone technology has advanced to the point where it has become common in the professional AV industry, with the most common applications being conference rooms, boardrooms, and huddle rooms. Background noise is heavily reduced in the output signal, so problems such as audio feedback, shuffling paperwork, quiet conversation in the background, HVAC noise, and acoustic reflections in the room are lessened. Through clever use of DSP algorithms, multiple users can be identified by their vocal “signature” and tracked as they move throughout the room.

These features produce a technology which significantly improves audio quality when compared to standard ceiling-mounted and boundary microphones. In addition, beamforming microphones can be installed in spaces with hard, reflective surfaces and high ceilings, which would otherwise present a challenge for most microphone solutions.

Click here to see an example of a beamforming microphone array at work.
So, the next time you are having difficulty hearing someone in a meeting, just think – you could be having an easier time locating submarines using beamforming technology.
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