When do you use omni-directional mics?

Every microphone has a pickup pattern. A microphone pickup pattern, also known as a polar pattern, refers to the way a microphone captures sound from different directions. The common types of pickup patterns include omnidirectional, unidirectional (cardioid, supercardioid, hypercardioid, lobar, etc.), and bidirectional (figure-8). The pickup pattern determines the microphone’s sensitivity to sounds coming from different angles. Using the correct pickup pattern can help reduce background noise and increase sound clarity.

Each pickup pattern is best suited for certain uses or situations. In this article, we will discuss the situations that are best suited to omnidirectional microphones.

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Why use an omnidirectional microphone

To capture sound from all directions:

Omnidirectional microphones are designed to pick up sound equally from all directions, which makes them well-suited for capturing sound in a 360-degree environment or for recording a group of people.

For natural sound reproduction:

Omnidirectional microphones are often used to capture a natural, uncolored sound, as they do not have the proximity effect (increased bass response when the sound source is close to the microphone) that is common with directional microphones.

To capture a wide soundstage:

Omnidirectional microphones can capture a wide soundstage, which can be useful for recording music or other audio in a spacious environment.

To minimize handling noise:

Omnidirectional microphones are less sensitive to handling noise than directional microphones, which makes them a good choice for situations where the microphone may be moved or touched during recording.

Inside parabolic microphones:

Interestingly, omnidirectional mics are often used inside parabolic collectors to create the most directional pickup pattern available.  The all-encompassing pickup pattern ensures that the sound reflected off the entire surface of collector dish is captured by the mic.  More directional microphones may miss out on a significant portion of the reflected sound energy.

When to use an omnidirectional microphone

An omnidirectional microphone is best used in situations where you need to capture audio from all directions equally. An example of this would be a conference setting, where speakers might be moving around the room. Another example would be an interview where you want to capture ambient noise along with the subject’s voice.

When not to use an omnidirectional microphone

This type of microphone is not ideal for recording a single focused source of sound, such as a musical instrument, as it will also pick up unwanted background noise.

Conclusion

Overall, omnidirectional microphones can be a useful tool in a number of audio recording and sound reinforcement applications. However, it can also cause poor audio if used improperly and unwanted sounds are captured.

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