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Tech Showcase: Boundary Mics and Auto Mic Mixers

The products listed here are typical of the hardware now available to make it all come together seamlessly.

Boundary mics and auto mixers make a great combination in environments where there is no audio operator but only on-mic participants and the sound system has to be a turnkey operation. Such environments are a growing trend in part because the tools available today have never been smarter and easier to use. The variety of installation options is enough to challenge creativity in designers and integrators but it always comes back to the basic rule of having a well-thought-out plan that serves the specific client in their own facility. The products listed here are typical of the hardware now available to make it all come together seamlessly.


The PZM10 professional flush-mount boundary layer microphone from AKG can be very inconspicuously mounted in conference tables, walls, and ceilings to clearly pick up voices for recording, conferencing, and surveillance. Its hemispherical polar pattern and the choice of mic or line level output provide installation flexibility while the selection of XLR or unterminated output connections allows it to be connected to any sound system that has 12-48V phantom power available. AKG’s new DMM14 U reference digital automatic microphone mixer has 12-band graphic EQ on all outputs, six programmable presets, and it can interface with networks for two-channel USB streaming in and out. Filters, ducking, compressor/limiter, and routing enable the mixer to serve in a wide variety of acoustic environments. The UL version adds the network connectivity and the ULD model provides 22 free assignable Dante outputs and four Dante inputs.

Audio-Technica ATND971

Is it a microphone or a network device?In the case of Audio-Technica’s ATND971 cardioid condenser boundary microphone with Dante network output, the answer is both. The inexpensive network twisted pair connects directly to the mic and allows it to communicate across an existing network of Dante-enabled devices and to control them with its integrated, programmable switch. The red/green LED status indicator shows the control setting to the user for operating the room lights, cameras, and other devices. Users have local and remote control of mic gain, low-cut filter and the LED indicator while the microphone is powered by PoE. With these mics, the whole system is scalable on the 512 bidirectional audio channels that Dante offers. The polar pattern is half-cardioid with a frequency response of 30Hz to 20kHz and the 18dB per octave bass roll-off starts at 80Hz.

Audix ADX60

Not limited to the conference room, the Audix ADX60 pre-polarized boundary condenser microphone can handle sound pickup at greater distance for other applications. The stock model has a hemi-cardioid pickup pattern on its modular threaded capsule but it is also available with hypercardioid and omni capsules to broaden the list of installation scenarios. Operating on 9V to 52V, the ADX60 produces a frequency response of 15Hz to 18kHz and a signal to noise ratio of 65dB. The 65mm-wide case is die cast from zinc alloy and it interfaces with the mixer using a 25ft. cable with a female miniature XLR running through the supplied APS910 phantom power adapter. The case features a black e-coat finish along with its laser etched model and serial number. A carrying pouch is also supplied.

beyerdynamic MPR 210 B

The MPR 210 B desktop microphone from beyerdynamic uses its patented Revoluto array technology with integrated microphone capsules to create a corridor characteristic for better voice pickup at a distance. The back electret condenser transducer produces a 130Hz to 17kHz frequency response with a maximum SPL rating of 112dB at 1kHz. The low-profile metal housing is unobtrusive for miking podiums, tables, or even ceiling-mount installations, and it is available in a black or white finish. The MPR 211B has several selectable operating modes including On/Off, Push-to-Talk, and Push-to-Mute, all selected at the bottom of the unit. The illuminated LED on the microphone button and the LED on the left-hand side indicate that the microphone is on. Through its control output, external devices can be triggered with the button on the mic case.

CAD Audio 930VPL

A key feature that CAD Audio added to the 930VPL condenser boundary microphone is the continuously variable polar pattern that can be used to custom tailor the mic pickup for the room where it is used. Additionally, the mic is built to reject interference from cell phones and other communication devices. Multiple modes of operation can be set with the DIP switch on the bottom of the case and the logic input can remotely control the LED as well as the membrane-switch activation. This makes the 930VPL especially well-suited to function with automatic mixers, teleconferencing systems, and control systems. The unit produces a frequency response of 90Hz to 17kHz and a maximum SPL spec of 120dB. The mic’s integral 80Hz, 12dB/octave high-pass filter removes unwanted low-frequency energy to improve intelligibility while the keyhole mounting slots can secure the body to a specific location.

Clockaudio ARM102-RF

The CS-S Series single-element boundary microphones from Clockaudio have an electronic capacitive touch switch for pop-free on/off switching and all models run on 12VDC from a regulated power supply. The red/green LED indicates the on/off condition of the unit. The CS-S Series mics provide a half-cardioid polar pattern and a frequency response of 50Hz to 18kHz. These microphones are made from solid brass and they are permanently mounted with the use of an M 20 x 1 bolt and nut. Each mic is connected to a 6.6ft. balanced audio line with open-ended termination. The integral phantom power adapter is equipped with filters for GSM frequencies from 800 MHz-1.2GHz. The ARM 102-RF digital motorized Retracta back electret condenser microphone is available in Black Nextel or Satin Nickel finish and it exhibits a cardioid polar pattern. The mic is motor driven and automatically retracts to show only 3mm protruding above the table surface.

Clockaudio CS3

From audio legend Dan Dugan, the Dugan Sound Design Model M unites all of the system’s well-known speech algorithms with Dante connectivity. The Model M can handle 32 channels of automixing at 96K or 64 channels at 48K with primary and secondary Dante network connectors and it is Power over Ethernet (PoE) capable. The unit’s scene memory can write and recall all of the operating settings, either globally or by group, in a stored settings library. As with the other digital Dugan mixers, the Model N can be controlled from its front panel, the Dugan Control Panel for Java (supplied free), the updated Dugan Control Panel for iPad (coming soon), and/or the Dugan Model K Tactile Control Panel. The front panel features a complete miniature Dugan Control Panel on a bright OLED display, operated by navigation keys and a rotary encoder for setting values.

Earthworks IMBL30

Earthworks designed the IMB and IMBL boundary microphones to fit perfectly into a conference table so that each takes up no more room than a coin lying flat on the surface. Available in black, white, or silver finish, the IMB and IMBL mics provide 30kHz flat frequency response in a true semisphere pattern while running on 48VDC phantom power. Each one features shielding against cellphones and other RF noise and the IMBL has a red/green Lumicomm LED Touch Ring that can be used to turn the mic on and off or perform any programmable function. The IMBL system interface board is powered from an external power source of 8VDC to 28VDC @ 85 to 170mA. The audio output is on 3-pin XLR and the maximum rated acoustic input is 136dB SPL.

Lectrosonics SPN 1612

The Lectrosonics Aspen SPN1612 uses its Proportional Gain Algorithm and TCP/IP addressability to provide smooth automixing and to blend its functions with those of any other audio system. The unit can be custom configured with a variety of circuit board assemblies to present an array of input/output combinations in a 1RU or 2RU rack frame. Between multiple units, automatic slave/master detection makes configuration quick and easy with Aspen Control Protocol capability through Ethernet, RS232, USB, and logic I/O ports. Each output has a signal processing chain, gain control, and limiter ahead of the digital to analog converter and the automixing can operate in a variety of modes. Each input can be used for microphone or line level signals with gain adjustable from -10 to +60dB. With a computer connected to the master unit in the system, setup, filters, and other changes are immediately heard.

MXL AC-410W and 424

MXL Microphones is introducing three new additions to its popular AC Series web conferencing line: the AC-424 USB Boundary Web Conferencing Microphone, and the AC-410W Wireless USB Web Conferencing Microphone. The MXL AC-424 is similar to the AC-404 but with enhanced features, such as a mute button, adjustable sensitivity switch, and a headphone out. Users can adjust the sensitivity switch to suit the size of the room. It has three capsules for a 180-degree pickup range. The AC-424 has a new, contoured body style. It connects to a computer via a USB cable with mini plug. The MXL AC-410W Wireless USB Boundary Microphone delivers sound from the microphone to the USB receiver and it operates in the 2.4GHz band. It features high-speed, low-latency audio transmission with a 20Hz to 20kHz audio bandwidth. The AC-410W operates on AA disposable or rechargeable batteries.

Rane AM2 Automixer

The AM2 Automixer puts eight-input control in a single rack unit frame and Rane has added the capability to use the RAD and cascade ports to team up to eight AM2’s for a total of 64 inputs, each of which can be mic, line, or mic with phantom power. The output is also switchable between line and mic level, and has its own level setting knob. Each input includes a rotary gain control along with signal presence and overload LEDs. The AM2 is optimized for automixing speech and its mic inputs have a fixed 100Hz to 7kHz bandpass filter to provide the best voice-only automatic mixing using the gain-sharing algorithm. Firmware updates can be done by using the front panel USB port. Rear panel fault, locate, USB, and power indicators aid with installation and diagnostics.

RCF AX 8042

The AX 8042 DSP Matrix-Mixer and Automixer from RCF-USA is designed for installation and commercial applications with its eight universal mic-line inputs, one of which can be used as a noise detection input, and it provides six outputs on four lines. The In/Out RJ 45 digital ports on the rear panel allow a second AX 8042 to be linked to create a 16 input, 12 output matrix. The serial control port can be set to work with the RCF TS 9918 remote control, or with third-party systems. The configurable automatic level control is set up by using input 8 to connect a noise detection microphone. The control is then assignable to any output or group of outputs. The unit also offers configurable parametric EQs, gates, compressors, limiters, delays, priority levels, automatic gain control, levels, gains on in-out and cross points, auto-mixer operations and filters in addition to programmable logic inputs and outputs.

Revolabs Elite Wired Mics

For the conference environment, there is a versatile performer in the Elite Wired Microphones line from Revolabs with several color options and a choice of pickup patterns. The form factor matches the Executive Elite Wireless Microphones so they can be easily used together. With high rejection of GSM noise with Revolabs RF Armour, the new wired line can also be mounted in place on a table using the optional permanent-mounting adapter with the cable routed through the conference table invisibly into the bottom of the microphone. These units provide a frequency response of 50Hz to 20kHz and a signal to noise ratio (with the omni pattern) of 70dB. Each one includes 25ft. of three-wire shielded mic cable and they run on 9-51VDC phantom power.

Sennheiser e901

The e 912 S boundary microphone from Sennheiser is optimized for picking up speech and it exhibits a half-cardioid pickup pattern. The programmable membrane switch on the case can be DIP switch configured for on/off, Push-to-Talk, or as a cough button. The frequency response can be set for instrument or voice pickup by using a second DIP switch combination. The rubber damping plate on the base insulates the mic from table thumps and vibration. The unit connects with a gold-plated XLR and all of the electronics are integrated into the microphone case rather than using an inline preamp. The mic runs on 48V phantom power and it handles a maximum 134dB SPL.

Shure MX690

Shure designed several handy features into the MX690 Microflex wireless boundary microphone including a microprocessor controlled transmitter, a bi-color status indicator, and a programmable mute function. Operating on two AA batteries, the MX690 provides a battery level indication and it has a logic output for remote LED and mute control. For simple transmitter/receiver frequency synchronization, it can use an IR link to the receiver. The mic has a cardioid pickup pattern and a frequency response of 50Hz to 17kHz. Meanwhile,the SCM820 8-channel digital IntelliMix automatic mixer provides eight mic or line level inputs and eight dedicated impedance balanced direct outputs that allow it to be used as an input processor. Controllable through third-party operating devices such as those from Crestron and AMX, the mixer has networking capability and digital/analog connectivity. LED meter rings display input audio or IntelliMix gain levels for each channel.

Shure SCM820


Intended to provide superior speech reproduction, the TOA EM700 has a hemispherical pickup pattern for use on meetings and lectures. The wide 30Hz-20kHz frequency response delivers high-quality speech while operating on 9VDC to 52VDC phantom power. It connects with an XLR at the end of a 24ft. 3-conductor cable. The low-cut filter with its switch on the mic bottom operates at 100Hz and slopes at -12dB per octave to cut table bumping and low-frequency background noise. The body is die-cast aluminum with a matte black finish.

Yamaha MA2030

The MA2030 power amplifier from Yamaha Commercial Audio can be connected via Cat-5 cable to the low-cost optional DCP1V1S wall-controller panel to provide control without direct physical access to the amplifier. Among the many DSP features on the MA2030 is automatic ducking that adjusts the background program level when a microphone input is detected and it has automatic leveling that keeps the master volume level constant during changes in source sound levels. Add to this a feedback suppressor, speaker EQ, high-and low-impedance speaker outputs and the ability to connect the PA2030 to drive more speakers and set up multi-zone operation. The Class D amplifier is small enough to fit just about anywhere and operate without cooling fans. More Online





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Yamaha Commercial Audio

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