What Is an Omnidirectional Microphone? (Answered)

Omnidirectional microphones are a type of microphone that can pick up sound in all directions. They are used in various applications, such as recording speeches, music, and interviews. This type of microphone is often preferred because it reduces noise and improves audio quality.

In this article, we will discuss how omnidirectional microphones work and how they can be used to improve your audio recordings. So if you’re an aspiring music professional or just curious about omnidirectional microphones, this post is for you!

What is an omnidirectional microphone? An omnidirectional microphone can pick up sound coming from any direction.

What is an omnidirectional microphone?

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

In Greek, “Omni” means “everyone.” That’s why it’s important to have an omnidirectional microphone, 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.

How do they work?

An omnidirectional microphone’s primary quality is that it picks 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.

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.

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.

A pressure-gradient microphone creates high pressure on one side and low pressure on the other when plosive energy travels through it. A “pop” will result from the diaphragm being overloaded. Vocal plosives are far less likely to occur when just one side of the diaphragm is open, as with pressure-principled omnidirectional microphones.

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.

What are the benefits and drawbacks of using an omnidirectional microphone?

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

Advantages of omnidirectional microphones

These are just a few benefits you can experience when using an omoni mic.

1. 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.

2. 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.

3. 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.

4. 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

These are just a few drawbacks you can experience when using an omoni mic.

1. 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.

2. 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.

3. Not great for live performacnes

When used for live sound reinforcement, however, putting an omnidirectional microphone close to a speaker or amplifier could cause problems with feedback.

When should you use an omnidirectional microphone?

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

1. Recordign a group ensable

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.

2. 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.

Frequently asked questions (FAQ)

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

Conclusion

Well, 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.

However, just as you can’t become an expert cyclist by reading a book, you can’t become a great music producer by reading articles alone. It’s time to take action! Go and put what you have learned into practice.

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

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.
• Extra tips:
  • A unidirectional mic may be preferable to an omnidirectional one for vocals because it blocks unwanted sound. 

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.

Helpful resources

• Omnidirectional and Directional Mics: What’s the difference?
• Audio Solutions Question of the Week: What Is Microphone Polar Pattern? (Part 1: Omnidirectional)
• Omnidirectional microphones that are apt for all your recording needs | Most Searched Products – Times of India