Shure Beta 91A Half-Cardioid Condenser Boundary Mic

• 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

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