What Is an Omnidirectional Microphone? (A Beginner’s Guide)

I often get asked about omnidirectional microphone features. In this post, I will answer this question and more about how it works.

If you’re a recording enthusiast or someone who wants to delve into the world of audio technology, understanding the ins and outs of different microphone types is essential. In this article, we’ll explore the concept of omnidirectional microphones, shedding light on their unique features and capabilities. So, whether you’re a content creator, podcaster, or simply curious about audio equipment, this guide will provide an overview of what an omnidirectional microphone is and how it can enhance your recordings.

What is an omnidirectional microphone? An omnidirectional microphone is a type of microphone that captures sound from all directions. It has a 360-degree pickup pattern, allowing it to capture sound equally from all angles.

What is an omnidirectional microphone?

Omnidirectional microphones are mics that can pick up sound from all directions. They are used for various purposes, including recording speeches, music, and interviews. This type of microphone is commonly used because it reduces noise and improves audio quality.

Image of a gold colored microphone on a black stand with a black pop filter on it. Source: jean balzan, pexels
Image of a gold colored microphone on a black stand with a black pop filter on it. Source: jean balzan, pexels

In Greek, “Omni” means “everyone.” That’s why having an omnidirectional microphone is important, which can record sound from any direction. They can be especially handy during live performances of plays and musicals when several instruments and voices need to be picked up at once.

If you’re recording a band for background music or a live podcast with a small studio audience, consider using an omnidirectional microphone to pick up the room’s sound.

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My favorite MIDI keyboard (at the moment):

AKAI Professional MPK Mini MK3

What is an omnidirectional microphone? (a beginner's guide) | 717qmgla7zl. Ac sl1500 | audio apartment
My favorite MIDI keyboard (at the moment):

AKAI Professional MPK Mini MK3

I’m loving the AKAI MPK Mini MK3 for its compact design and the range of controls. It’s one of my essential tools. The velocity-sensitive keys and MPC-style pads are great for making beats, while the thumbstick and knobs give me precise control.

How do omnidirectional microphones work?

An omnidirectional microphone’s primary quality is picking up sound equally well from all directions. The sound pressure does not change how the diaphragm moves in a microphone, regardless of the direction from which the sound is coming from.

The pressure principle says that only one side of a microphone’s diaphragm is exposed to the sound pressure in the room. The back end is sealed in a chamber with a constant pressure very close to atmospheric pressure.

The pressure principle says that only one side of a microphone’s diaphragm is exposed to the sound pressure in the room.

Therefore, only the diaphragm’s front half responds to acoustic pressure changes. The diaphragm contracts when the sound pressure is higher than the surrounding air. The diaphragm gets bigger when the sound pressure is lower than the air pressure around it.

When the pressure of a sound wave is lower than the pressure of the air around it, the diaphragm moves outward. The diaphragm collapses inward when the opposite is true. The variation in this motion triggers the mic’s output signal.

What are the characteristics of an omni-microphone?

Below are the important features of an omnidirectional microphone.

  1. Equally sensitive to sound from all directions: An omnidirectional microphone can pick up sound from any direction because only one side of its diaphragm is exposed to the pressure of the sound field around it.
  2. Pressure principle in single-diaphragm microphones: Only one side of a microphone’s diaphragm is exposed to the sound pressure in the room. The back end is sealed in a chamber with a constant pressure very close to atmospheric pressure.
  3. No null points: Because it is sensitive to sounds coming from all directions, the omnidirectional microphone has no dead spots. However, this lowers its gain-before-feedback and hurts its ability to separate and reject sound sources.
  4. No lobes of sensitivity: Since Omni microphones are sensitive in every direction, you won’t have to worry about picking up unwanted sensitivity lows or harsh high sports.
  5. It does not exhibit a proximity effect: One side of the diaphragm is exposed to environmental sound pressure, so It does not exhibit a proximity effect. Only pressure-gradient microphones, which have diaphragms open on both sides to sound pressure, are affected by being close. This is because the difference in low-frequency amplitude between the two sides of the diaphragm is bigger than in the low-frequency phase.
  6. Resistant to vocal plosives: Omnidirectional microphones are much less likely to get broken by voice plosives than their directional counterparts. Again, this is because the diaphragms of omnidirectional microphones are shielded from sound pressure on all sides but one.
  7. Resistant to wind noise: Unlike directional microphones, which are more susceptible to wind noise and gusts, omnidirectional microphones are less so.
  8. Most natural-sounding polar pattern: An Omni mic will record sounds from all directions with the same frequency response because it has no off-axis coloration. With an omnidirectional microphone, the sound quality stays the same no matter where it goes.
  9. Becomes more directional at higher frequencies: Omnidirectional mics become more directional when used at higher frequencies. This happens with short-wavelength, high-frequency sounds. To effectively move the diaphragm, high-frequency sound waves have a more difficult time penetrating the microphone’s physical body from behind.

Advantages and disadvantages of using an omnidirectional microphone?

There are a few pros and cons to using an omnidirectional microphone.

Advantages of omnidirectional microphones

  • Lower plosive sounds: Words beginning with “P” or “B” are referred to as “plosives” or “popping noises.” More plosives are made when the wind blows through the acoustic ports of a directional or unidirectional microphone. This is smaller with omnidirectional models.
  • Less proximity effect: The proximity effect causes the sound to be more bassy when the source is closer to the microphone. Therefore, the proximity impact of omnidirectional devices is less than that of directional microphones.
  • Less handling or vibration sound: Low-end frequencies include handling and vibration noises. Since the proximity effect of omnidirectional devices is lower, they are less likely to pick up unwanted low-frequency vibration or handling noise.
  • Flexible positioning: It doesn’t matter which way you hold an omnidirectional model—whether upright, upside down, or any other way—the pickup will be the same.

Disadvantages of omnidirectional microphones

  • Does not focus on one particular thing: Using an omnidirectional model is bad if you want to focus on the source of a sound without picking up the room’s ambient noise.
  • You can’t isolate recorded sounds easily: It is important to separate each sound you record so you can change its volume without changing the volume of the other sounds in the mix. For example, suppose a guitarist is playing with a singer. In that case, an omnidirectional microphone will pick up both the voice and the guitar, making it hard to adjust the volume of each separately.
  • Not great for live performances: When used for live sound reinforcement, however, putting an omnidirectional microphone close to a speaker or amplifier could cause problems with feedback.
Image of a gray microphone on a black stand. Source: pavel danilyuk, pexels
Image of a gray microphone on a black stand. Source: pavel danilyuk, pexels

When should you use an omnidirectional microphone?

So when should you use an Omni mic? Here are a few use cases when using an omnidirectional microphone.

  • Recording a group: A typical use is placing a single omnidirectional microphone in the middle of a circle and having everyone face the microphone while singing. The approach eliminates the need for a complicated multi-microphone setup for recording ensembles of any kind, whether they are barbershop singers, a classical string quartet, a bluegrass band, a folk band, a drum circle, etc.
  • Great for capturing the sound of the audience: Whether we’re talking about wired or wireless, omnidirectional microphones are the best choice when an audience needs to pick up sound from around them.

If you want even more tips and insights, watch this video called “Thoughts on omnidirectional microphones.” from the NordicAudioLabs YouTube channel.

A video called “Thoughts on omnidirectional microphones.” from the NordicAudioLabs YouTube channel.

Frequently asked questions (FAQ)

Do you still have questions? Below are some of the most commonly asked questions about omnidirectional microphones.

What is the difference between omnidirectional and directional microphones?

Omnidirectional microphones can pick up sound from any direction, while directional microphones are tuned to a certain direction.

Is omnidirectional or unidirectional better?

A unidirectional mic is preferable to an omnidirectional mic because it blocks out unwanted sound. A unidirectional mic will allow you to capture it more clearly if you’re recording a single person’s voice, and that is the sole focus.

Does omnidirectionality benefit vocals?

Omnidirectional microphones are not ideal for voice recordings.

Conclusion

There you have it! An omnidirectional microphone does exactly what it says. Just make sure that you choose a high-quality microphone if you want to get the best results.

So, do you prefer to use omnidirectional microphones? And did I cover everything you wanted to know? Let me know in the comments section below (I read and reply to every comment). If you found this article helpful, share it with a friend and check out my full blog for more tips and tricks on music production. Thanks for reading, and never stop making music.

Key takeaways

This article covered what an omnidirectional microphone is, how they work, and the features of omnidirectional microphones. Here are some key takeaways:

  • In Greek, “Omni” means “everyone.”
  • An omnidirectional microphone t picks up sound equally well from all directions. 
  • The omnidirectional microphone has no dead spots.
  • A unidirectional mic may be preferable to an omnidirectional one for vocals because it blocks unwanted sound. 

Helpful resources

Image Andrew Ash
Written by Andrew Ash, Staff Writer

Hey there! My name is Andrew, and I'm relatively new to music production, but I've been learning a ton, and documenting my journey along the way. That's why I started this blog. If you want to improve your home studio setup and learn more along with me, this is the place for you!

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Edited by Nick Eggert, Staff Editor

Nick is our staff editor and co-founder. He has a passion for writing, editing, and website development. His expertise lies in shaping content with precision and managing digital spaces with a keen eye for detail.

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