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At first glance, a boundary mic may not look so special because of its flat and low-profile design. However, if you know where to optimally place these boundary microphones in a room or on top of a conference table, they can reproduce a natural sound to a superior level that can envelop the entire area.
From the name itself, boundary microphones are recording devices that are placed on a boundary surface to capture reflective sounds. These condenser microphones with a small microphone capsule are made to capture and record spoken word applications with their flat and unobtrusive designs.
Boundary microphones are commonly used in conference rooms and meeting rooms. They can either be wired or wireless and their polar patterns vary depending on the model.
Similar to how other microphones work, boundary microphones convert sound waves into electrical energy becoming the audio signal. The waves this microphone captures are the reflective sounds bounced from the boundary surface it is strategically placed in. For that reason, the position and angle of boundary microphones play a direct role in their sound quality.
The distinct design of boundary microphones also plays a huge role in how these microphones work. The flat shape of this microphone allows it to be placed in more strategic spots and surfaces where the enhancement of signal-to-noise ratio and reduction of ambient noise can be achieved.
The microphone capsule of these mics is mounted slightly above the flat surface place so it can easily be installed against flat tops such as a conference table, walls, floors, and ceilings. With such a design, the sound wave bounced from the surfaces and reflected the microphone to create a pressure maximum.
These microphones are often used in spoken word applications and settings because of their design, features, and natural sound quality reproduction. While these microphones are often used in meeting rooms and conference rooms, their ability to pick up audio from multiple sources has also made them useful in churches, sports arenas, stage presentations, small musical ensembles, and even recording studios.
How you position and angle these mics can make or break their audio reproduction and quality. Knowing this microphone’s optimal placement and special positioning can help you produce clear and natural acoustics with little reverb, echo, and noises coming from surfaces and multiple sources.
A boundary microphone is best placed on a flat area, such as a conference table, at least 2 feet in front of the audio source. A microphone with a cardioid polar pattern is best for this distance and placement as it will focus on picking up the audio that is directly in front of it.
Should your microphone have a super cardioid or omnidirectional polar pattern, the 2 feet distance rule still applies. However, you should be mindful that this microphone may pick up several voices and audio sources in the meeting room because of the wide range it can cover so it is best to place them on strategic surfaces with the least signal-to-noise ratio.
To create a cardioid pickup pattern for your microphone, regardless if it has a supercardioid or omnidirectional pattern, the angle it is placed in changes the reflected audio. The diaphragm of the microphone capsule can be positioned 60 degrees parallel to and facing the microphone plate to delay the audio reflected. This 120-degree angle of acceptance also helps in decreasing comb filter interference, which happens when the microphone peaks and valleys.
Multiple microphones are often installed in a room for more audio coverage and pickup. With more than one microphone in the room, peaks and dips may occur if several of them are turned on at the same time. To avoid this occurrence, the 3:1 Rule is a common practice that is best applied.
The 3:1 Rule basically states that a microphone should have three times the distance between its source and the next nearest microphone. This distance can avoid phasing issues and will create at least a 10 dB level difference.
To maximize and get the most out of these microphones, it is best to know the optimal placement and position they should be mounted in. By knowing so, the overall audio quality it can pick up and reproduces can superiorly encompass the room.
If you’re looking at elevating the next office conference call, class lecture, or meeting, then it might be time to take a look at the best boundary microphones currently out there.