Audio-Technica U851A Cardioid Condenser Boundary Microphone

The Audio-Technica U851A is a boundary microphone for surface-mount applications. It operates in a cardioid/half-cardioid polar pattern, though its condenser-element is switchable. Offering a frequency range of 30 Hz to 20 kHz, this microphone works with an AA battery as well as phantom power, and boasts an SPL of 123 dB to 133 dB depending on the method of power used.


  • Designed for surface-mount applications such as sound reinforcement, conferencing, television sound, and more
  • Rotating output connector allows XLR cable to exit from the back or the bottom of the microphone, depending on your preference
  • Off-axis rejection for maximum gain before microphone feedback
  • Rejection of RFI (radio frequency interference) through UniGuard technology
  • Small-diameter capsule near boundary for eliminating phase-distortion whilst delivering a high-output signal
  • Steep low-frequency attenuation for increased sonic response without affecting vocal quality
  • Durable casing
  • Non-slip silicone foam pads minimize coupling and other problems due to surface-to-surface microphone vibration
  • Operates on battery or phantom power