The Shure BETA 91A is a professional condenser microphone specifically engineered for close-miking kick drums and other low-frequency percussion instruments. Its unique half-cardioid polar pattern and sleek, low-profile design allow it to be placed directly on the internal cushion or on a stand-mounted plate inside a kick drum, capturing the powerful attack and deep resonance with exceptional clarity. Unlike traditional dynamic kick drum microphones, the BETA 91A utilizes a condenser capsule that provides a faster transient response and wider frequency range, resulting in a detailed sound that accurately reproduces the beater's impact and the drum's fundamental tone.

This boundary-style microphone is designed to be used in a pressure zone, which increases its sensitivity and provides a smoother low-end response by minimizing phase cancellations. It includes a built-in 3-position tilt-response switch, allowing engineers to tailor the low-frequency response to suit different drum heads, playing styles, and musical genres. This feature is crucial for dialing in the perfect balance of attack and body, whether for a punchy rock sound, a resonant jazz tone, or a tight electronic feel. The microphone requires 11-52V phantom power and features a -15dB pad to handle the extreme sound pressure levels generated by a kick drum.

The BETA 91A's durable steel mesh grille and solid construction make it roadworthy for touring applications. Often used in conjunction with a dynamic kick drum mic placed outside the drum's port, it provides a comprehensive sonic picture of the kick drum. Its precise, articulate sound has made it an industry standard for both live sound reinforcement and studio recording, valued for its ability to deliver a consistent, defined low-end that cuts through any mix.