The Directional Patterns of Microphones
One device that needs no introduction but at the same time requires significant know-how to aid making the right choice is a microphone.
Despite not needing an introduction, it is only fitting that an attempt be made to explain this well-known tool.
A microphone is a device that converts sound waves into electrical signals. These electrical signals can then be amplified, recorded, or transmitted. A microphone is designed to capture and reinforce a particular sound captured from a sound source.
Microphones are vital tools in many fields—music, broadcasting, filmmaking, conferencing and many more. They can be standalone or integrated into devices to capture sound.
Now that an explanation has been given to the device called a microphone, let us look into a significantly overlooked aspect of microphones - Directional Patterns. Microphone directional patterns play a crucial role in determining and shaping the quality of sound.
This blog post will help you understand the different directional patterns of microphones so you can find one that aligns perfectly with your specific need, desired sound, and the type of background noise you aim to eliminate.
Understanding Directional Patterns
A microphone’s directional pattern can be referred to as a mic’s listening zone. This means the direction the mic best hears or catches sounds. It inevitably affects how and in what setting a type of microphone is best used. Simply put, a directional pattern is the microphone's sensitivity to sound in relation to directions and angles around the microphone head.
Quite a number of different directional patterns are available, which are plotted in graphs known as polar patterns. What a polar pattern shows is the variation in sensitivity, 360 degrees around the microphone, with the knowledge that the microphone is at the centre and that 0 degrees represents the front.
Whether you are a freelancer, orator, film buff, musician, or podcaster, having a clear understanding of these patterns will unlock the potential to capture the perfect audio.
Types of Microphone Directional Patterns
There are three basic types:
- Omnidirectional Microphones
- Unidirectional Microphones
- Bidirectional Microphones
Omnidirectional Microphones
An omnidirectional microphone has a circular polar pattern, which evenly picks up sounds from all directions. They are sensitive to sound and pick up everything within a 360-degree radius. Known to capture multiple sound sources in a natural and unfiltered manner, omnidirectional microphones are a popular choice for recording acoustic set-ups, classical orchestras, and even spoken interviews.
One potential drawback of using an omnidirectional microphone is its ability to capture even the slightest sounds from your surroundings. Alternatively, if you desire to capture the encompassing ambiance of your environment, including the diverse sounds emanating from different areas of the room, it would be perfect to consider an omnidirectional microphone. Note that omnidirectional mics might not be the best for live performances.
Examples of omnidirectional microphones include:
- Saramonic LavMicro U1A Omnidirectional Lavalier Microphone
- Saramonic LavMicro U2 Omnidirectional Lavalier Microphone
- Shure MX391 Microflex Omnidirectional Boundary Microphone
- Revolabs Executive Elite Omnidirectional Tabletop Wireless Microphone
Unidirectional Microphones
Unidirectional microphones are most sensitive to sound arriving from directly in front—the angle referred to as 0 degrees—and less sensitive in other directions. This makes unidirectional microphones effective at isolating the desired on-axis sound from both unwanted off-axis sound and ambient noise. In this category of unidirectional microphones are three main polar patterns:
Cardioid
The cardioid directional pattern gets its name from its resemblance to a heart shape and it captures sound primarily from the front. Their pick-up area is wide on-axis and they have maximum rejection at 180 degrees off-axis, which allows for high gain before feedback. Microphones with cardioid patterns have the highest level of sensitivity in the front and the lowest level of sensitivity in the rear, making it ideal for a wide range of recording purposes.
The cardioid pattern is particularly effective at isolating dry signals, minimising any unwanted room acoustics or background noise. This pattern is excellent for vocals or any close mic application. It is perfect for on-stage performance because of its excellent isolation capability that prevents feedback from the crowds.
Audix ADX10 Miniature Cardioid Condenser Lavalier Microphone, Shure CVL Centraverse Cardioid Lavalier Microphone, Shure MX185 - Cardioid Wired Lavalier Microphone, and Sennheiser MKE 40 - Cardioid Lavalier Microphone are examples of cardioid microphones.
Hypercardioid
Hypercardioid microphones have an extremely narrow directionality, which captures sound from the rear at 105 degrees. These types of mics are designed to provide superior isolation and increased resistance to feedback from behind. They are perfect for situations with high-volume levels but require precise microphone placement techniques because even the slightest positional adjustments can easily dislodge them. If you are looking for a relaxed acoustic gig, then this is the perfect fit for you.
Some hypercardioid microphones include:
- Audix M55WHC Hypercardioid Hanging Ceiling Microphone with Height AdjustmentAudix
- Hypercardioid Boundary Microphone with Logic Remote (Black, down cable)
- Audio-Technica PRO8HEx Hypercardioid Dynamic Headworn Microphone
Supercardioid
Supercardioid microphone patterns have a narrower pickup pattern than hypercardioid, with a more focused rear pickup of 115 degrees. The microphones in this category offer excellent ambient sound rejection from behind, with the least sensitivity at 125 degrees.
Due to the nature of the supercardioid directional pattern, it is often used on the live stage—both during concerts as well as spoken-word events—to capture the focused sound of an instrument or voice. The narrow-angle of sensitivity helps to minimise the bleeding from other sounds on a busy stage.
AKG PCC130SW Supercardioid Boundary Layer Microphone with Programmable Switch, Shure MX392/S Microflex Supercardioid Boundary Microphone, Audix M55WS Supercardioid Hanging Ceiling Microphone with Height Adjustment, and Shure MX184 Supercardioid Wired Lavalier Microphone are examples of cardioid microphones.
Note: In choosing a unidirectional microphone, the smallest movement on a hypercardioid has a higher tendency to affect the microphone’s performance when compared to a cardioid or supercardioid.
- Bidirectional Microphones
The bidirectional microphone is designed to pick up sound from only two directions: from behind and in front of the microphone. The bidirectional polar pattern is also known as the figure-8 polar pattern because the shape of the pickup area forms the outline of a figure-8.
They produce a very good, open, and natural sound like omnidirectional microphones, which is a good choice for picking up two opposing sound sources. Having a pickup angle of about 90 degrees at both the front and rear, its ambient pickup is the same as that of the cardioid.
Bidirectional microphones front and back sensitivity ability make them ideal for capturing a duet performance and studio recording.
Examples of bidirectional microphones include:
Shure RPM181/BI Bi-directional capsule for Beta 181 microphone
Conclusion
Sound has a tremendous impact on our lives, and microphones and their directional patterns reflect this by fusing technology, artistry, and inclusivity in a way that transcends boundaries.
With this knowledge of microphones' directional patterns, you are well on your way to begin or improve your microphone journey.
Need a helping hand on this journey? Not only does our website have an array of options to choose from, but our service desk is ever ready to assist at hello@paykobo.com.
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