What is a Boundary Microphone?

A boundary microphone, sometimes called a PZM (pressure zone microphone), is a microphone designed to be placed on a flat surface such as a table, wall, or stage floor. It captures sound by detecting pressure changes in the boundary area between the surface and the surrounding air.

By placing the microphone directly against a surface, boundary microphones reduce phase interference caused by sound reflections. This design helps produce a clearer and more natural sound, especially when recording multiple speakers or ambient audio.

Boundary microphones are commonly used in conference rooms, theaters, boardrooms, and stage productions. They are often placed on tables or floors to capture dialogue, group discussions, or stage performances without the need for visible microphone stands.