Shure BETA 91A Half-Cardioid Condenser Microphone
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).

Features

• 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

Specifications

• 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

Manufacturer:

SHURE