Just as with aviation and radio, boundary microphones and automatic microphone mixers represent brother technologies that grew up together. In conference scenarios where attaching microphones to everyone is not practical, boundary mics allow some flexibility in placement while preserving mobility of participants. Automatic microphone mixers dramatically improve sound quality in free form discussion formats. As shown here, each continues to excel in its own realm.
Bringing the feature of user configurability to the conference room, the AKG CBL301 triple element low profile boundary microphone includes a red, green, and blue ring LED to indicate mic talk/mute status. The variable, 270 to 360-degree cardioid pickup pattern is phantom powered by a 24VDC to 48VDC supply and it has the talk/mute control on the housing edge. The black finish blends well and unobtrusively in the conference environment. 
The company’s AKG DMM14UL automatic mic mixer is used to handle unscripted discussion common to conference formats. Capable of being cascaded to ten units using RJ-45 connections, this model can control microphones in as many as 140 channels. Creative additional features include stereo recording outputs on RCA terminals and one stereo USB output. The ULD version also provides a Dante output. The mixer fits a single rack space and the front panel has twin stereo output LED meters. Each input is accessed through a 3-pin Phoenix terminal as are two balanced master outputs. Remote control is possible through a 3-pin Phoenix connection for RS-232 serial signals. External control can also be done using the mixer’s rear panel RJ-45 LAN connector.
The Audio-Technica ES964 boundary microphone array is intended for use in small conference rooms and online conferences. This model’s single omnidirectional and twin bidirectional elements can be configured to create variable polar pickup patterns and it is designed for use with AudioTechnica Digital SmartMixers and other compatible mixers. For users around a conference table, the mic has three separate on/off/mute buttons along the edge and the LED ring lights to show which of these conditions the mic is in at any time. The ES964 requires a 20-52VDC power supply and exhibits a 20Hz-15kHz frequency response. 
With the AudioTechnica ATDM-0604a digital smartmixer, channels can be selected in gate or sharing mode to minimize feedback and reverberant sound response. Users can adjust input and output gain levels, create and recall presets and turn on phantom power through front panel controls or from a Windows-based PC, Mac, iOS or Android device. There are six balanced Mic/Line input and one unbalanced stereo input, along with two balanced and one unbalanced stereo outputs. Network and USB ports allow the mixer’s capacity to be expanded to as many as eight units.
There is a versatile mix of applications for the Audix ADX60 professional pre-polarized boundary condenser microphone operating on a 9-52VDC phantom power supply. The 12mm capsule, die cast zinc housing, and steel mesh grille make it durable and reliable while the female mini XLR connector saves space. The microphone comes with a 25ft. cable, carrying pouch, and the APS910 phantom power adapter. Its 50Hz-18kHz frequency response provides full bodied sound for cardoid pattern voice pickup. The ADX60 is designed to handle up to 130dB SPL. Available as an option, the APS911 battery operated phantom power adapter is equipped with an on-off switch and bass roll-off.
From conferencing to kick drums, the beyerdynamic TG D71 can handle the most demanding environments with is high 148dB SPL capability and no-slip rubber underside covering. The red LED on the case lights to indicate when the phantom power supply is in use and the mic is ready for operation. The audio connection is a full-size XLR to take the wear and tear of road use with no special adapters necessary. The 25Hz-20kHz frequency response allows a wide range of applications including piano pickup and its half cardoid pattern rejects background noise.
Conference rooms, huddle rooms, classrooms and recorded meetings can all sound and operate better with the CAD Audio U5 USB condenser boundary microphone. It rejects background sound with its internal noise cancellation and the volume and mute control buttons allow participants easy, uncomplicated operation. With its omnidirectional pickup pattern and -30dB sensitivity, the mic can hear participants up to 20ft. away and the 20Hz-10kHz frequency response gets realistic voice quality. An indicator LED on the top glows red to show mute and blue to indicate the mic is active.
Taking advantage of easy placement and maximum noise rejection, the ClearOne Uni-Directional Tabletop Microphone gets solid voice quality with its 50Hz-18kHz frequency response and sensitivity of -65dB. The integrated low-cut filter is featured to remove room rumble and table thumps. The unidirectional pattern also contributes to background sound rejection and the mic includes a 23ft. cable with an XLR connector at the mixer end. It operates on 9-52VDC phantom power, and its low profile keeps it out of the way. This model’s high 141dB maximum SPL rating provides great help in avoiding avoid distortion.
The Clockaudio ARM 202-RF can hide in plain sight while doing its job with two independent encapsulations in a tough brass housing. The cardioid capsules are installed pointing 180 degrees from each other and can pick up sound from both sides of the table while providing RF filtered output. The mic runs on 9-48VDC and there is a built-in phantom power module. When ready to use, the motorized unit rises into position and then lowers to minimum profile when done. The 15Hz-18kHz frequency response assures accurate voice reproduction.
Built-in EQ, an integrated pop filter, strong steel screen, and a half-cardioid pickup pattern are part of the Electro-Voice RE90B boundary layer microphone. Barely half an inch high, the black or white mic housing can blend with the room décor and the rubber feet on the bottom keep the die cast zinc case safe from slipping on the table surface. This condenser mic is run by 9-52VDC phantom power and exhibits an 80Hz-15kHz frequency response (+/- 3dB) which is suitable for videoconferencing, classrooms, and churches. The connector on the attached mic cable is a 3-pin XLR.
The Sennheiser e901 condenser boundary plate microphone can handle a wide range of applications from percussion instruments to pianos to videoconferences. For strength, a standard size XLR connector is used to eliminate the need for any adapters. This condenser mic operates on a 48VDC phantom power supply and exhibits a half-cardioid pickup pattern with a frequency response spec of 20Hz-20kHz. The rubber damping plate prevents slippage and helps isolate the housing from table thumps. There are also two mounting slots for wall installation
The biggest name in automixing is Dan
Dugan, the inventor and pioneer developer of this technology and the Dugan Sound Design E-3A Automatic Mixing Controller is one of his most advanced creations. While taking size to the minimum it raises functionality to the maximum with 16 AES channels and 16 ADAT. There is a word clock on a BNC connector and channels may be grouped into three independent automixers. This model is Power over Ethernet (PoE) capable, and it features a six-bus pre/post matrix mixer. All of its formidable automixing power fits into a single rack space.
It’s like taking a recording studio on the road with the Sound Devices Scorpio premium portable mixer-recorder, a 32 channel, 12 bus, 36 track machine. These devices include 32 channels of Dante I/O and 16 ultra-low noise, 8-Series microphone preamplifiers. Recording is done on 256GB internal SSD through two SD card slots. For the automix, it offers Dugan Automixing/ MixAssist for up to 16 channels. The fully-customizable routing matrix allows any input to be sent to any channel, bus, or output and all of this capability is in an over-the-shoulder unit that can go anywhere. The award-winning Scorpio uses FPGA-based audio processing with 64-bit data paths for the best in sound quality and it includes built-in analog limiters, high pass filters, delay, 3-band EQ and phantom power.
The durable all-metal case and grill let the MXL AC-44 miniature USB C mobile microphone take any kind of carry-around punishment and still be ready to go with its three-capsule 180-degree cardioid pattern and 25ft. pickup range. Covering only a 2.5in. by 3in. area of table, the mic rises just an inch above the surface. In addition, there is a very useful line level direct analog feed on a 3.5mm connector. Energized by USB bus power, the AC-44 produces a 30Hz–20kHz frequency response. It is supplied with a 6ft. USB Type C to USB Type A cable.
Just introduced at InfoComm, the new RDL NP-NMP44 network mixing processor features six networked 4×1 virtual audio mixers for Dante/AES67 signals and any pair of them can be configured for stereo sound. There is also automatic (VOX) priority ducking assignable on each virtual mixer along with an adjustable ducking threshold, attenuation level and recovery delay. Four presets for routing, mixing, and levels can be easily stored and recalled. The unit has front panel LED indicators for power and network sync. All of this can be run on PoE through the RJ-45 network connection or on a separate 24VDC 150mA power supply.
A metal housing, EQ switch, and a red LED
indicator are all part of the RCF MC 5002 Professional Desktop Microphone professional desktop microphone. When the mic is on, the LED clearly indicates it and the 5-pole mini XLR connector includes dry contact points. With the unidirectional pickup pattern, the mic can simply be pointed at the desired source and other room sounds are minimized. The 50Hz-18kHz frequency response and -58dB sensitivity allow good voice recognition by conference participants. The tiny white case extends only 1.34in. above the table surface.
One of the more versatile models in the boundary mic arena, the Shure MX396 Microflex multi-element boundary microphone is a multi-element system with a separate output for each element and a selection of 360-degree, 300-degree, or bi-directional polar patterns. It comes in two or three-element configurations. Equipped with a bi-color status indicator, the mic can be permanently installed in the conference table and configured through bottom mounted DIP switches, one of which is a 150Hz low cut switch. The unit may also be muted through the action of an automatic mixer. 
Among the automixers available, the Shure Intellimix P300 audio conferencing processor is capable of connecting ten Dante audio inputs, two analog inputs, USB and a mobile device to a room or PC based conferencing system. To these it can apply AEC, automatic mixing, auto gain control, compression, peaking filters, matrix mixing, and delay. The mixer can operate on PoE without the need for a separate power supply. The mixer can be integrated into a conferencing system using Shure Designer 6.0 software and the front panel LEDs show an array of parameters including network status, power, and clipping.
It’s one thing to have sophisticated automixing capabilities in the studio or post suite but it is quite another to take it on the road and keep it working in that tough environment. The award winning Sound Devices Scorpio does exactly that with its Dugan Automixing/MixAssist for up to 16 channels. This 32-channel, 36 track mixer-recorder can store sound on a 256 GB internal SSD and there are two external SD slots that can be recorded onto simultaneously with the internal storage. Location microphone inputs use 16 ultra-low noise, 8-Series microphone preamplifiers. The front panel screen is bright enough to read in sunlight along with the LED metering.
With only a 1.1in. diameter, the TOA EM600 has the absolute minimum visual profile after it is flush mounted into a wall, table, or ceiling. To minimize the effect of any surface vibration or room rumble, there are two rubber isolation rings and a 50Hz low-cut filter. This condenser mic operates on 9-52VDC phantom power with an omnidirectional pickup pattern and 30Hz-20kHz frequency response. The body is steel with a white semigloss finish and the head is zinc-plated steel wire. Completely out of sight is the cable connection on the bottom of the housing. 
At the mixing end of the TOA product line is the innovative TOA D-901 digital mixer featuring auto-ducking and NOM which automatically adjusts the input gain of open microphones corresponding to the number of open microphones in the system. As many as 16 preset patterns can be stored in memory and instantly recalled. Third party control systems can operate the mixer via RS-232 serial control. At the front panel has an LCD screen and setting keys and knobs for local control and adjustment. The 12 inputs, 8 buses, and 8 outputs fit into a 3RU rack-mount housing.
With the Yamaha RM-TT tabletop array microphone it is possible to select from six different pickup patterns for the ultimate in room customization. This mic supports Dante and PoE on the same RJ-45 terminal and it can track conference presenters as they move around the table. It also has advanced features such as adaptive echo cancellation, auto gain control, noise reduction, and reverberation suppression. Among selectable pickup patterns are omnidirectional, toroidal, cardioid, super-cardioid, hyper-cardioid, and bidirectional. The frequency response of 160 Hz- 16kHz (-10 dB) is fine for conference voice pickup. 
Also from Yamaha is the 3RU rack mounted Yamaha MRX7-D signal processor for central management of multiple sound systems and it can be configured and controlled through a device layout wizard, functional setup, and third-party control systems. There is a 64 x 64 matrix to handle the most complex signal routing requirements and Dan Dugan automixing is built-in along with acoustic echo cancellation and ambient noise compensation. The front panel includes an SD card slot for playback, LEDs for input/output signal status, and peak level LEDs. Smooth expandability is assured through the Mini-YGDAI card slot
