Extraneous sound — noise — is so ubiquitous that we often don't notice it as our brains engage in organic noise mitigation. City dwellers subliminally tune out the din of honking car horns, rumbling trucks, and passing airliners. Our brains even subconsciously account for so-called ambient noise such as the whoosh of HVAC vents. But once a meeting starts, as most IT managers and directors know, all that noise can suddenly become front and center. Thus, technology with noise-filtering capabilities have never been more important for hybrid meetings.
Individual distracting noise sources — like a loud clock or a creaking chair — can often be easily identified and eliminated. Externally generated noise — like traffic — can be mitigated using a combination of barriers (like soundproof walls or isolated-wall construction) and technology (whether sound masking or automatic ambient noise reduction). Internal noise — like room echoes and reverberation that interfere with speech intelligibility — can be addressed with an array of acoustical techniques or products (like an absorptive acoustical wall or ceiling treatments).
Some noise sources are simply part of the meeting process itself: the tapping of multiple laptop keyboards, computer cooling fans, coughs and throat clearing, and so on. They are the sounds of life but can become distracting. Videoconferencing can exacerbate these when you layer in remote spaces' acoustical and environmental noises outside of the IT manager's control.
Before identifying a technical solution, you must first determine the sonic caliber of the meeting space. That's done by measuring its signal-to-noise (S/N) ratio. Simply put, that's the difference between the space's noise level versus its desired sound level, all measured in decibels (dBs). For instance, typical speech level is estimated to be around 65 dB. In a room with 50-dB of ambient noise, the S/N ratio is 15 dB, while a room with just 40 dB of background noise has an S/N of 25 dB. Thus, the higher the S/N value, the better.
Noise filtering — or noise reduction and noise suppression — is the removal or mitigation of unwanted sound from desired sound. A number of techniques support audible noise reduction, at the core of which is beam-steering or beam-forming. These are arrays of microphone elements that can be controlled and aimed via digital signal processing (DSP). There are two broad types: With static or passive beam-steering, the microphone array picks up sound from a coverage area specified by the DSP unit's programming and rejects sound from outside that coverage area. Adaptive-dynamic beam-forming follows the movements of the desired sound, such as a presenter moving between displays within a room, while still tuning out unwanted sound. Understandably, this requires more complex processing.
Poor audio quality is a measurable detriment to overall meeting quality, and noise — whether it originates in the meeting room or outside it — is a leading cause of poor audio experience. A study in the British Journal of Psychology demonstrates how noise negatively impacts productivity. Subpar audio quality during online meetings compels participants to put more effort into listening. That's not as positive as it sounds; it results in what's known as "effortful listening," which can lead to reduced memory recall as well as higher stress levels, and ultimately, meeting fatigue.
A growing number of compact videoconferencing solutions incorporate beam-steering technology. An excellent example is the Bose Professional Videobar VB1, which has six integrated beam-steering microphones that automatically focus on the voices in the room and reject noise. The VB1 integrates both static and adaptive dynamic beam-forming processing to support use in a wide range of room types. Additionally, up to three "exclusion zones" — areas in a room in which the microphones will ignore any sound — can be programmed in. That performance is further bolstered by an Auto-EQ feature that optimizes the audio's frequency response for all meeting participants.