Shure BETA 91A

• 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

The primary use of the Beta 91A is kick drums. It can also be used for other low frequency applications including piano.
The Beta 91A is a half cardioid condenser boundary microphone. You can expect a strong low end response as it is specifically tailored for bass frequency applications, and superior attack and punch for studio quality sound even at extremely high sound pressure levels (SPL).
The Beta 91A features a new and updated microphone capsule. The new capsule will result in a more natural high frequency response than the Beta 91.

Cartridge Type Electret Condenser
Polar Pattern Half-cardioid (cardioid in hemisphere above mounting surface)
Frequency Response 20 to 20,000 Hz
Output Impedance @ 1 kHz 146 Ω
Sensitivity open circuit voltage, @ 1 kHz, typical –48.5 dBV/Pa[1] (3.8 mV)
Maximum SPL 1 kHz at 1% THD[2] 2500 Ω load 155 dB, 1000 Ω load 151 dB
Signal-to-Noise Ratio[3] 64.5 dB
Dynamic Range @ 1 kHz 2500 Ω load 125.5 dB, 1000 Ω load 121.5 dB
Clipping Level 20 Hz to 20 kHz, 1% THD 2500 Ω load 12.5 dBV, 1000 Ω load 7.5 dBV
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
Connector Three-pin professional audio (XLR), male, balanced
Polarity Positive pressure on diaphragm produces positive voltage on pin 2 with respect to pin 3
Power Requirements 11–52 V DC[4] phantom power (IEC-61938), 5.4 mA