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Audio-Technica U851Rb Cardioid Condenser Boundary Microphone (Black)

BH #AUU851RB • MFR #U851RB
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Audio-Technica U851Rb Cardioid Condenser Boundary Microphone (Black)
Key Features
  • For Surface-Mount Applications
  • High-Output Condenser Element
  • Cardioid Polar Pattern
  • Reduces Off-Axis Sound Pickup
Achieve clear, intelligible speech reproduction with the black Audio-Technica U851Rb, a cardioid condenser boundary microphone optimized for surface-mount applications in conference rooms, houses of worship, recording studios, live event venues, and sports arenas. The high-output condenser element yields a wide frequency response of 20 Hz to 20 kHz, which can be modified via the switchable 80 Hz low-cut filter—ideal for mitigating rumble and low-frequency buildup.

The cardioid polar pattern delivers directional pickup and enhanced off-axis rejection, allowing reduced ambience and high gain before feedback. Thanks to the UniGuard RFI-shielding technology, the U851Rb impedes radio frequency interference from sources such as wireless devices, fluorescent lights, air conditioners, and more. It can be powered by 11 to 52 VDC phantom power, so no batteries or external power supplies are required. The rotatable balanced TB3M output connects to the included 25' TA3F to XLR microphone cable, ensuring easy hookup to your mixer, preamplifier, or audio interface.
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Audio-Technica U851R Overview

Achieve clear, intelligible speech reproduction with the black Audio-Technica U851Rb, a cardioid condenser boundary microphone optimized for surface-mount applications in conference rooms, houses of worship, recording studios, live event venues, and sports arenas. The high-output condenser element yields a wide frequency response of 20 Hz to 20 kHz, which can be modified via the switchable 80 Hz low-cut filter—ideal for mitigating rumble and low-frequency buildup.

The cardioid polar pattern delivers directional pickup and enhanced off-axis rejection, allowing reduced ambience and high gain before feedback. Thanks to the UniGuard RFI-shielding technology, the U851Rb impedes radio frequency interference from sources such as wireless devices, fluorescent lights, air conditioners, and more. It can be powered by 11 to 52 VDC phantom power, so no batteries or external power supplies are required. The rotatable balanced TB3M output connects to the included 25' TA3F to XLR microphone cable, ensuring easy hookup to your mixer, preamplifier, or audio interface.

  • Cardioid condenser boundary microphone
  • Designed for surface-mount applications such as high-quality sound reinforcement, professional recording, television, and conferencing
  • Superior off-axis rejection for maximum gain before feedback
  • PivotPoint rotating output connector allows cable to exit from either the rear or the bottom of the microphone
  • Small-diameter UniPoint element near boundary eliminates phase distortion and delivers clear, high-output performance
  • Separately available interchangeable elements permit angle of acceptance from 100° to 360°
  • UniGuard RFI-shielding technology offers outstanding rejection of radio-frequency interference (RFI)
  • Switchable 18 dB/octave UniSteep roll-off filter at 80 Hz
  • Self-contained electronics eliminate need for external power module
  • Powered via 11 to 52 VDC phantom power
  • Heavy die-cast case and non-slip silicone foam bottom pads minimize coupling of surface vibration to the microphone
  • Low-profile design with low-reflectance finish for minimum visibility
  • Threaded inserts on bottom of microphone allow it to be mounted with screws for increased security
  • Balanced TB3M output connector
  • Includes 25' TA3F to XLR male shielded microphone cable
EAN: 4961310146689

Audio-Technica U851R Specs

Key Specs
Microphone Type
Boundary
Polar Pattern
Cardioid
Element Type
Electret Condenser
Controls
Low Cut/HPF
Frequency Response
20 Hz to 20 kHz
Maximum SPL
134 dB
Analog Output
1x TB3M/Mini-XLR 3-Pin Male
Power Sources
Phantom Power
Microphone
Microphone Type
Boundary
Polar Pattern
Cardioid
Element Type
Electret Condenser
Sound Field
Mono
Controls
Low Cut/HPF
Pad
No
Filter & EQ
Low-Cut Filter: 80 Hz
Circuitry
Solid-State
Performance
Frequency Response
20 Hz to 20 kHz
Maximum SPL
134 dB
Sensitivity
-34 dBV/Pa
Dynamic Range
108 dB
Connectivity
Analog Output Connector
1x TB3M/Mini-XLR 3-Pin Male
Cable Length
25' / 7.62 m
Power
Power Sources
Phantom Power
Operating Voltage
11 to 52 V
Physical
Color
Black
Weight
8.9 oz / 253 g
Packaging Info
Package Weight
1.365 lb
Box Dimensions (LxWxH)
10.5 x 5.5 x 2.9"

Audio-Technica U851R Reviews

See any errors on this page?

Can you recommend a preamp/power supply for this ...

Can you recommend a preamp/power supply for this mic? I don't need a mixer as I plan to feed the mic into an ATEM mini with an adapter
Asked by: Mark
You can use the Rolls MP13 Mini-Mic Preamp (B&H # ROMP13) to power the Audio-Technica U851Rb Cardioid Condenser Boundary Microphone, then use an XLR female to 3.5mm TRS male cable like the Kopul XRSM 3-Pin XLR Female to 3.5mm RA Stereo Mini-Plug Cable - 3' (B&H # KOXRSM03B) to connect the output from the MP13 to the 3.5mm TRS input on the Blackmagic Design ATEM Mini HDMI Switcher.
Answered by: Lisa S
Date published: 2023-03-19

Would this work upside down? I want to mount it to

Would this work upside down? I want to mount it to a ceiling.
Asked by: grant
The Audio-Technica U851RWb Cardioid Condenser Boundary Microphone (White) is a desktop microphone. It is not designed to be mounted on a ceiling. Since the microphone has an optimal distance range of 1-3 ft, mounting it on a ceiling will generate feedback and increase background noise.
Answered by: Daniel O
Date published: 2026-07-18
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