Beamforming Microphones in the Modern Boardroom

The table boundary microphone was a reasonable solution for conference rooms built around a conference phone. Everybody leaned in when they needed to be heard. Nobody sat at the far end of the table during a video call. These were accepted behaviors because there was no alternative.

Beamforming ceiling arrays removed the constraint. A correctly installed ceiling array covers every seat at the table with a dedicated acoustic beam, tracks speakers as they move or stand, and rejects HVAC noise, projector fans, and the ambient room noise that table mics pick up indiscriminately. The result is a conference room where remote participants hear every seat without modification to meeting behavior. That shift in what is possible is why beamforming ceiling mics are now the standard in any serious boardroom. and why understanding the technology, the AI layer behind it, and the installation requirements is essential before specifying one.

The Acoustics Behind Beamforming

A beamforming microphone array is a collection of capsules. typically 8 to 37 depending on the model. arranged in a known geometric pattern. Each capsule captures the sound field at its position. The digital signal processor applies a set of time delays and amplitude weights to each capsule’s signal and sums them. When the delays are chosen correctly for a specific angle, signals arriving from that angle add constructively and signals arriving from other angles cancel partially. The result is a pickup pattern. a “beam”. that is directional in a way that a single capsule cannot be.

The key insight is that the beam is a mathematical construct, not a physical one. Changing the delay and weighting coefficients steers the beam to a different position without moving the hardware. A ceiling array with 20 capsules can form multiple simultaneous beams, each aimed at a different seat, all from the same fixed hardware. This is the geometric advantage over table mics: one device, correctly positioned, covers the entire table.

The physics constraint is reverberation. Beamforming rejects off-axis sound well. It does not reject sound arriving from the beam direction, including reverberation arriving from that direction. A room with hard parallel walls, a concrete floor, and a glass table has a reverberation time that overwhelms the directional advantage of the array. The target reverberation time (RT60) for a conference room is 0.4 to 0.5 seconds. Most untreated commercial conference rooms are at 0.6 to 0.9 seconds. Acoustic treatment. absorptive ceiling panels, carpet, upholstered furniture, soft wall finishes. brings the room into the correct range before the microphone performs as specified. The treatment work comes before the microphone is installed. This is the most commonly skipped step in boardroom AV projects.

AI Beam Steering: From Rules to Machine Learning

Early beamforming systems used rules-based steering: the processor monitored signal level across the array, identified which beam zone had the highest level, and activated that beam. The problem is that level is an imperfect proxy for speech. HVAC noise has level. A chair moving across the floor has level. A projector fan has level. Rules-based systems activate beams on noise events, producing audible beam-switching artifacts and picking up non-speech signals that get transmitted to remote participants.

The shift to machine learning changed this fundamentally. The Shure MXA920 and the Sennheiser TeamConnect Ceiling 2 both run on-board AI models trained to classify audio signals as speech or non-speech before making any beam-steering decision. The model evaluates spectral characteristics, temporal patterns, and signal coherence across the array. not just level. A chair scrape has high level but wrong spectral and temporal characteristics for speech. The AI model correctly classifies it as non-speech and does not activate a beam. A person speaking at the far end of the table at moderate level has the right characteristics. The beam steers to that position.

The Shure MXA920 takes this further with its Autofocus technology. Rather than requiring an installer to define fixed beam zones during commissioning, the MXA920’s AI model learns the room geometry through an initial acoustic analysis, infers where the table is from the reflection pattern, and establishes coverage zones without manual configuration. This does not eliminate the need for a skilled integrator. the microphone still requires proper height, centering, and DSP integration. but it reduces one of the more time-consuming commissioning steps and produces better coverage in rooms where the table geometry does not fit a simple rectangular zone definition.

The Sennheiser TeamConnect Ceiling 2 uses a similar ML-driven approach with its Dynamic Beamforming technology. The TC2 forms up to 64 simultaneous beams across its circular capsule array, covering an area up to 80 square meters. The AI steering layer continuously re-evaluates which beams carry speech-probable signals and adjusts the active beam set accordingly. For large boardrooms with irregular seating or rooms where participants frequently stand and move, the TC2’s continuous adaptation outperforms fixed-zone systems that require recommissioning when the furniture layout changes.

Biamp’s Parle ceiling microphones use a different architecture. the beamforming processing is handled by the Tesira DSP rather than on the microphone itself. This keeps the microphone hardware simpler but requires the Tesira platform for full functionality. The tradeoff is that the AI processing capability is determined by the Tesira firmware rather than the microphone hardware, which can be updated centrally across all rooms using a common DSP platform.

Ceiling Tile vs Pendant Mounting

Ceiling tile mounting is the default installation for most commercial offices: the microphone drops into a standard 24x24 ceiling grid tile, with a plenum-rated cable running above to a DSP or network switch. The installation is clean and matches the existing ceiling aesthetic. The constraint is ceiling height. most commercial offices have 9-to-11-foot ceilings, which is within the coverage specification of the major ceiling array products. Below 8.5 feet, some arrays approach the edge of their rated coverage radius.

Pendant mounting suspends the microphone from a rigid or flexible arm below the finished ceiling, positioning it closer to the table surface. Pendant installation is appropriate in rooms with very high ceilings (above 14 feet) where a ceiling-flush mount would place the microphone too far from the talkers to capture adequate level. Pendant mounting introduces a different aesthetic consideration and requires coordination with the structural and MEP teams for the suspension point. it is not a field decision made during installation day.

Integration with Crestron Flex and Q-SYS

The microphone does not operate in isolation. It connects to a DSP, which handles echo cancellation, noise gating, auto-leveling, and the acoustic reference signal from the loudspeaker system. Without proper echo cancellation reference, the DSP cannot separate the microphone’s pickup of the room’s loudspeakers from the talker’s voice, and remote participants hear an echo of their own speech.

Shure MXA systems connect to Crestron Flex via USB audio or Dante. In a Crestron Flex UC-ENGINE configuration, the Shure MXA provides multi-channel audio to the Crestron DSP layer, which handles echo cancellation referenced against the far-end audio signal from the Teams or Zoom session. Shure’s Designer software configures the beam zones and IntelliMix processing parameters, while the Crestron control layer manages the microphone mute state in response to call events.

In a Q-SYS deployment, Shure MXA and Sennheiser TC2 both connect via Dante with dedicated Q-SYS plugins. The plugin exposes beam status, mute state, microphone gain, and acoustic environment metrics to the Q-SYS design file. The Q-SYS designer can build logic that switches beam configurations when a room-combining partition opens, mutes all microphones when no call is active, or adjusts noise gate thresholds based on the time of day. This level of integration is what makes Q-SYS the right DSP platform for complex multi-room environments, as covered in our post on Q-SYS for corporate AV.

Common Installation Mistakes

Off-center placement is the most damaging error. A beamforming array mounted 18 inches off the centerline of the table produces uneven coverage. beams on one side of the table are closer than specified, beams on the other side are at the edge of coverage. The result sounds like one half of the table is closer to the microphone than the other, which is exactly what is happening.

Skipping room acoustic treatment before commissioning is the second most common mistake. Integrators commission a microphone in an untreated room, adjust the beam zones to get acceptable pickup, and hand the room over. Three weeks later, the client reports that remote participants say the room sounds echoey. It was echoey at commissioning too. the engineer normalized to the reverberant environment. Treating the room after commissioning means re-commissioning the microphone, which is an avoidable cost.

Incorrect echo cancellation reference is third. If the acoustic echo cancellation reference signal does not match the actual loudspeaker output. because the signal routing through the DSP introduces latency that was not compensated, or because the reference is taken from a pre-amplifier stage rather than the loudspeaker output. the echo cancellation fails and remote participants hear room echo regardless of how well the beamforming is configured.

If you are specifying a boardroom microphone system in NJ, NY, or CT, our conference room design practice includes an acoustic site assessment before any hardware is specified. The assessment determines the room treatment requirement, the appropriate microphone platform, and the DSP configuration. in that order. Schedule a consultation or reach our team at 201.405.2022.