The Shure MX391 is a professional omnidirectional boundary layer microphone engineered for clear, natural sound capture in fixed installation environments. Utilizing the pressure zone microphone principle, its condenser capsule is positioned flush with the surface of its low-profile housing, which minimizes phase cancellations and comb filtering that typically occur when sound reflects off a hard surface. This design results in a smooth, extended frequency response with exceptional clarity, making it ideal for capturing group discussions, conference proceedings, and lectern presentations in boardrooms, courtrooms, classrooms, and houses of worship. Its omnidirectional polar pattern provides even 360-degree pickup, ensuring all participants seated around a table or within its range are heard with consistent quality.

The microphone's robust, low-profile rectangular housing is designed for permanent mounting on tables, walls, or ceilings, offering a discreet and unobtrusive aesthetic that blends into professional settings. The unit features a threaded insert for secure mounting and includes a foam windscreen to reduce plosive sounds and minor airflow noise. Its reliable performance is backed by a durable construction built to withstand the daily use of high-traffic commercial spaces. The MX391 connects via a standard three-pin XLR output, providing straightforward integration into existing analog audio systems, mixing consoles, or digital signal processors, requiring standard 11-52V phantom power for operation.

As a core component of Shure's Microflex line for installed sound, the MX391 delivers reliable, set-and-forget performance. It excels in applications where a single, centrally located microphone is needed to capture the sound of a room or a specific zone with natural tonality and minimal coloration. Its simplicity, combined with the acoustic benefits of boundary layer technology, makes it a trusted choice for audio consultants and system integrators seeking a dependable solution for speech reinforcement, conferencing, and recording in demanding professional environments.