Shure BETA 91A

The Shure Beta 91A is designed for use with kick drums, as well as other traditional low-frequency applications including piano. Featuring an updated microphone capsule, integrated preamplifier, and XLR connection, Beta 91A offers a strong low-frequency response and is specifically tailored for bass frequency applications. The Beta 91A combines superior attack and punch for studio-quality sound, even at extremely high sound pressure levels (SPL).

Type
Electret Condenser

Frequency Response
20 to 20,000 Hz

Polar Pattern
Half-cardioid (cardioid in hemisphere above mounting surface)

Impedance
146 Ohms

Sensitivity (at 1 kHz, open circuit voltage)
-48.5 dBV/Pa (3.8mV)
1 Pascal=94 dB SPL

Maximum SPL (1 kHz at 1% THD)
1000 Ohm load: 151 dB, 2500 Ohm load: 155 dB

Signal-to-Noise Ratio (referenced at 94 dB SPL at 1 kHz)
64 dB
S/N ratio is difference between 94 dB SPL and equivalent SPL of self noise, A-weighted

Dynamic Range (at 1 kHz)
1000 Ohm load: 121.5 dB
2500 Ohm load: 125.5 dB

Common Mode Rejection (20 Hz to 20 kHz)
> 55 dB

Clipping Level (20Hz-20 kHz at 1% THD)
1000 Ohm load: 7.50 dBV, 2500 Ohm load: 12.5 dBV
THD of microphone preamplifier when applied input signal is equivalent to cartridge output at specified SPL

Self Noise (typical, equivalent SPL, A-weighted)
29.5 dB SPL-A

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

Weight
Net: 470 g (16.6 oz.)

Frequency Contour Switch
7 dB of attenuation centered at 400 kHz

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

Power Requirements
11-52 Vdc phantom power, 5.6 mA