Half-Cardioid Condenser Microphone

Precision-engineered. Integrated preamp. Two-position contour switch for kick drum & other low-frequency applications.


  • Uniform half-cardioid polar pattern for maximum gain-before-feedback and rejection of off-axis sound
  • Precision-engineered low-profile design features integrated preamplifier and XLR connector to maximize setup efficiency while minimizing stage clutter
  • Frequency response tailored for kick drum/low frequency applications with a wide dynamic range for use in high SPL environments
  • Two-position contour switch to maximize attack and clarity depending on application: select the flat response setting for natural sound in most applications or the “low-mid scoop” setting for a strong low frequency “punch” with plenty of higher frequency attack
  • Requires no external mounting or accessories for ease of use and storage
  • Furnished with zipper pouch

Shure BETA 91A: half-cardioid Kick Drum Microphone



  • Electret Condenser

Frequency Response

  • 20 to 20,000 Hz

Polar Pattern

  • Half-cardioid (cardioid in hemisphere above mounting surface)

Output Impedance

  • EIA rated at146 Ω


at 1kHz,open circuit voltage

  • -48.5 dBV/Pa(3.8 mV)[1]

Maximum SPL

1 kHz at 1% THD[2]

2500 Ω load 155  dB
1000 Ω load 151  dB

Signal-To-Noise Ratio[3]

  1. 64.5  dB

Dynamic Range

at 1kHz

2500 Ω load 125.5  dB
1000 Ω load 121.5  dB

Clipping Level

20 Hz to 20 kHz, at 1% THD

2500 Ω load 12.5  dB
1000 Ω load 7.5  dB

Self Noise

equivalent SPL, A-weighted, typical

  • 29.5  dB SPL-A

Common Mode Rejection

(20  Hz to 200 kHz)

  • ≥55  dB

Frequency Contour Switch

  • 7 dB of attenuation centered at 400 kHz

Power Requirements

  • 11–52  V DCphantom power[4], 5.4 mA


  • Positive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3


  • 470 g(16.6 oz.)


  • Three-pin professional audio (XLR), male, balanced

© 2020 by massmusiK