The Shure MX391 is a discreet and highly practical boundary microphone designed to capture clear, natural audio in conference rooms, boardrooms, courtrooms, and other fixed installation environments. Utilizing boundary layer technology, the microphone is engineered to be placed directly on a table surface or mounted flush into a ceiling. This positioning takes advantage of the acoustic principle whereby sound pressure doubles at a reflective boundary, resulting in increased sensitivity and a wider, more consistent pickup area. The cardioid polar pattern provides focused front-side pickup while effectively rejecting sound originating from the rear, helping to minimize room noise and feedback in sound reinforcement applications.

The low-profile design of the MX391 minimizes visual distraction, allowing it to blend seamlessly into the aesthetics of professional settings. Its durable construction is built to withstand the daily wear of a commercial environment. The microphone features an internal preamplifier that requires standard phantom power for operation, delivering a robust signal level suitable for long cable runs to a mixer or DSP. The semi-recessed mounting design simplifies installation on flat surfaces and helps to reduce handling noise. This combination of practical form factor and effective acoustic performance makes it an ideal solution for capturing group discussions, presentations, and teleconferencing audio where multiple speakers need to be covered evenly.

For systems integrators and AV professionals, the MX391 offers a reliable and sonically transparent tool for ensuring intelligible speech reinforcement and recording. Its predictable pickup pattern and boundary-layer efficiency allow for strategic placement to achieve optimal coverage with fewer microphones, streamlining system design and reducing potential phase issues. By delivering clear audio with high gain-before-feedback in a nearly invisible package, this microphone effectively addresses the core requirements of professional installed audio systems for conferencing and voice capture.