Boundary Microphone

What is a Boundary Microphone?

A boundary microphone, also known as a PZM (Pressure Zone Microphone) or a plate microphone, is a specialized type of microphone used in technology for capturing sound in specific environments. Unlike traditional microphones that are held or mounted on stands, boundary microphones are designed to be placed on flat surfaces, such as tables, floors, or walls. The unique design of a boundary microphone allows it to take advantage of the acoustic properties of the surface it is placed on. The microphone is typically mounted on a flat plate. This boundary acts as a sound reflector, capturing audio from all directions and using the surface to enhance the microphone’s performance.

Advantages of using a Boundary Microphone

One of the key advantages of a boundary microphone is its ability to achieve consistent and uniform sound pickup. When placed on a flat surface, it uses the boundary to create what is known as a “pressure zone.” This pressure zone allows the microphone to capture sound equally from all directions, resulting in a balanced and natural sound reproduction. It minimizes the “proximity effect”, which is the increase in bass response when a sound source is close to a regular microphone. This uniformity of sound pickup makes boundary microphones ideal for recording meetings, conferences, lectures, or group discussions.


Boundary microphones are often used in applications where capturing audio from a larger area is desired. For example, in conference rooms or boardrooms, a single boundary microphone placed in the center of the table can effectively capture the voices of multiple participants sitting around it. This eliminates the need for individual microphones for each person. This reduces clutter and simplifies the setup. The microphone’s placement on a surface also offers some practical benefits. It can be discreetly placed on a table or mounted on a wall, making it more attractive compared to traditional microphones on stands. This is particularly useful in situations where aesthetics or space constraints are a concern, such as in video conferencing setups or broadcast studios. These types of microphones are known for their excellent pickup of ambient sounds. They are designed to capture not only direct sound but also the natural reverb and room ambiance. This can be very useful in applications like recording live performances, theatrical productions, or sound reinforcement in large venues. Along with their use in audio recording and reinforcement, boundary microphones are found in teleconferencing systems, video production, surveillance, and more. They are often integrated into devices like conferencing units, podiums, boundary mixers, and public address systems. To maximize the effectiveness of a boundary microphone, proper placement is crucial. Positioning the microphone on a suitable surface, considering factors such as acoustic properties, proximity to sound sources is essential for optimal performance.

To sum up, a boundary microphone can be a better option for capturing audio in meetings, conferences, and other group settings. The discreet placement, excellent ambient sound pickup, and versatility of boundary microphones make them valuable tools in various technological applications, providing clear, balanced, and immersive sound reproduction.

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