Shure Beta 91A Condenser Boundary Microphone

Type: Electret Condenser

Frequency Response: 20 Hz to 20,000 Hz

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

Output Impedance: 146 Ohms

Sensitivity: –48.5 dBV/Pa (3.8 mV)

Maximum SPL: 155 dB (at 2500 Ohm load)

Signal-to-Noise Ratio: 64.5 dB

Dynamic Range: 125.5 dB

Self Noise: 29.5 dB SPL-A

Power Requirements: 11–52 V DC phantom power, 5.4 mA

Switch: Two-position frequency contour switch (Flat or Low-Mid Scoop)

Connector: Integrated 3-pin XLR (male)

Weight: 16.6 oz (470 g)

Tailored Frequency Response: Specifically voiced for kick drums and low-frequency instruments to provide studio-quality punch and clarity.

Integrated Preamp: Features a built-in XLR connector to reduce stage clutter and provide a more reliable, streamlined connection.

Two-Position Contour Switch: Includes a toggle to switch between a natural flat response and a "scooped" setting that enhances attack and low-end presence.

Half-Cardioid Polar Pattern: Optimized for maximum gain-before-feedback and rejection of background noise, ensuring your source remains the focus.

Low-Profile Design: No mounting hardware or stands required; the rugged, weighted construction stays securely in place inside the drum or on the floor.