Video conference bars integrate cameras, microphones, speakers, and audio processing into a compact device designed for meeting rooms. Unlike a single-microphone application, a VideoBar often uses multiple microphone capsules arranged in an array to capture speech from different positions around the room.
For manufacturers developing video conferencing equipment, selecting microphone capsules involves more than choosing individual components with suitable sensitivity and frequency response. Capsule consistency, array geometry, microphone placement, electrical matching, and signal processing all influence the performance of the complete system.
This guide explains the main considerations when selecting microphone capsules for VideoBar and other compact conference audio devices.
1. Understand the Audio Requirements of a Video Conference Bar
A VideoBar is typically designed to capture speech from participants seated at different positions in a meeting room. Depending on the product design, the microphone array may support automatic speaker tracking, beamforming, noise reduction, and other audio-processing functions.
Before selecting microphone capsules, define the intended application and performance requirements.
- Small meeting rooms: Capture speech from several participants within a relatively short distance.
- Medium-sized meeting rooms: Support wider seating arrangements and speech pickup from greater distances.
- All-in-one conference systems: Integrate microphone arrays into a compact enclosure alongside cameras and speakers.
- Portable conference devices: Balance microphone performance, power consumption, and limited installation space.
The expected pickup distance, number of participants, room acoustics, and audio-processing architecture should guide the capsule selection process.
2. Why Microphone Consistency Matters in an Array
A microphone array uses multiple capsules working together. Differences between individual capsules can affect the consistency of the signals received by the audio-processing system.
Important parameters to evaluate include:
- Sensitivity consistency: Large differences in output level between capsules can complicate channel balancing.
- Frequency response consistency: Similar frequency responses help maintain more consistent sound characteristics across array channels.
- Phase response: Phase differences can influence how signals combine, particularly in beamforming applications.
- Noise performance: Variations in self-noise may affect the balance between channels.
- Production repeatability: Consistent manufacturing and incoming inspection help maintain array performance across production batches.
For this reason, conference equipment manufacturers should define acceptable matching tolerances for the microphone array rather than evaluating each capsule only as an independent component.
3. Consider Microphone Placement and Array Geometry
The physical arrangement of microphone capsules is a fundamental part of array design. Capsule spacing, orientation, and position relative to the sound inlet all affect the signals received by the system.
Capsule spacing
The distance between microphones influences the array’s spatial response and the frequencies at which spatial interference may occur. Array spacing should therefore be designed together with the intended beamforming method and processing algorithm.
Microphone orientation
Capsule orientation should be consistent with the intended pickup pattern and the acoustic design of the enclosure. If directional capsules are used, their orientation becomes particularly important.
Enclosure and sound inlet design
The VideoBar housing can influence microphone response through openings, internal cavities, protective materials, and nearby components. The acoustic performance of a capsule installed inside the finished enclosure may differ from its open-air measurement.
Prototype evaluation should therefore use the actual enclosure and microphone positions whenever possible.
4. Evaluate Far-Field Voice Pickup Requirements
Many VideoBar designs need to capture speech from participants who are not sitting directly beside the device. This makes far-field voice pickup an important system-level requirement.
Several factors influence far-field performance:
- Capsule sensitivity: The output level should be compatible with the audio circuit and the expected sound pressure at the microphone.
- Self-noise: Low microphone and circuit noise can be important when capturing quieter speech at greater distances.
- Frequency response: The response should support the required speech reproduction and intelligibility.
- Array configuration: Microphone number, spacing, and geometry affect the system’s spatial processing capabilities.
- Signal processing: Beamforming, automatic gain control, echo cancellation, and noise reduction may contribute to the final result.
It is important to distinguish microphone sensitivity from pickup distance. A capsule with higher sensitivity does not automatically provide longer effective pickup range. The complete array, audio circuit, room conditions, and processing algorithm determine the practical result.
5. Account for Reverberation and Background Noise
Meeting rooms can have very different acoustic characteristics. Glass walls, hard floors, large tables, and other reflective surfaces may produce reverberation that affects speech intelligibility.
Air conditioning, projector fans, computer equipment, and conversations from nearby spaces can also introduce background noise.
When selecting microphone capsules for a VideoBar, consider the intended operating environment:
- Small meeting rooms: Focus on capturing nearby participants while maintaining consistent speech quality across seating positions.
- Medium-sized rooms: Evaluate far-field performance and the ability of the complete array to distinguish relevant speech.
- Reverberant rooms: Consider microphone placement, array design, and the capabilities of the audio-processing system.
- Noisy environments: Evaluate capsule self-noise, circuit noise, array processing, and the expected background sound level.
No microphone capsule can independently remove room reverberation or all background noise. These requirements should be addressed through coordinated acoustic, mechanical, and electronic design.
6. ECM and MEMS Options for Conference Microphone Arrays
Electret condenser microphone (ECM) capsules and MEMS microphones can both be considered for conference equipment, depending on the product architecture and manufacturing requirements.
ECM microphone capsules
ECM capsules may be suitable for array designs that use conventional microphone capsule formats. Manufacturers can evaluate capsule dimensions, directivity, sensitivity, frequency response, and electrical characteristics according to the array requirements.
For multi-channel applications, consistency between capsules is particularly important. The supplier’s manufacturing controls, specification tolerances, and batch consistency should be considered during component evaluation.
MEMS microphones
MEMS microphones may be appropriate for compact PCB-based arrays and designs that prioritize low-profile integration or automated surface-mount assembly.
Interface type, power requirements, PCB layout, acoustic port design, and channel synchronization should be considered when integrating MEMS microphones into a conference system.
The choice between ECM and MEMS should be based on the complete product requirements, including acoustic performance, available space, circuit architecture, and production process.
7. Electrical Matching and Array Calibration
Even when microphone capsules have similar nominal specifications, the final array may require channel-level calibration. This is especially relevant for systems that use beamforming or other multi-channel signal-processing methods.
During development, engineers should consider:
- Channel sensitivity matching: Evaluate output-level differences between microphone channels.
- Frequency response matching: Compare the response of individual capsules across the intended speech band.
- Phase and time-delay alignment: Account for channel differences and physical propagation distances within the array.
- PCB and circuit consistency: Review component tolerances and channel-to-channel differences in the audio signal path.
- Calibration strategy: Determine whether production calibration or software compensation is required.
Capsule consistency provides a useful foundation, but it does not replace system calibration. Array geometry, PCB layout, enclosure acoustics, and processing algorithms must all be considered.
8. A Practical Testing Process for VideoBar Manufacturers
Testing individual microphone capsules is an important first step, but the complete VideoBar should also be evaluated under representative meeting-room conditions.
A practical validation process can include:
- Individual capsule testing: Measure sensitivity, frequency response, self-noise, and other required acoustic parameters.
- Array consistency testing: Compare the capsules selected for each array and check whether they meet the project’s matching tolerances.
- Enclosure testing: Evaluate the microphone response after installation in the actual VideoBar housing.
- Multi-position speech testing: Assess speech capture from different seating positions and distances.
- Room acoustic testing: Evaluate performance in rooms with different reverberation and background-noise conditions.
- System-level testing: Check beamforming, echo cancellation, noise reduction, and other audio functions in the finished device.
- Production validation: Confirm that component matching and assembly processes can maintain consistent performance across production batches.
9. Information to Prepare When Sourcing Microphone Capsules
For OEM and ODM conference equipment projects, providing clear technical information helps suppliers evaluate suitable microphone capsule options.
- Intended product type, such as VideoBar or all-in-one conference equipment
- Required number of microphone channels
- Capsule dimensions and available installation space
- Preferred directivity and target pickup distance
- Sensitivity and frequency response requirements
- Required sensitivity and frequency response matching tolerances
- Electrical interface and audio circuit requirements
- Prototype quantity and expected production volume
For array applications, it is especially useful to provide the required matching tolerances and the intended calibration method. These details help establish whether the proposed capsule specifications are suitable for the complete system.
Conclusion
Selecting microphone capsules for video conference bars requires a system-level approach. Individual capsule specifications matter, but array consistency, microphone placement, capsule matching, room acoustics, and signal processing are equally important to the final audio performance.
For manufacturers developing multi-microphone conference systems, defining matching requirements early and validating the complete array can help reduce integration problems and improve production consistency.
ECMIC supplies microphone capsules for OEM and ODM applications. Conference equipment manufacturers can share their array configuration, acoustic requirements, matching tolerances, and project quantities to begin a technical evaluation.
