When looking for a microphone, it is important to understand every polar pattern to know which is suitable for you. So while you come across many polar patterns, you may have heard about supercardioid microphones. Here in this article, we are going to share detailed information about the same.
In this article, you will learn:
- What is a supercardioid microphone?
- supercardioid Microphone features
- How is the supercardioid pattern achieved?
- Where to use supercardioid microphones?
- List of miking techniques with the supercardioid pattern.
What are Supercardioid Microphones?
Supercardioid microphones may be misunderstood with cardioid polar patterns, but they actually differ in terms of directionality. A supercardioid microphone is more directional than a cardioid microphone.
They have a better directional polar pattern; the supercardioid polar pattern is more sensitive to the X-axis; it is a mic point with null points at 127 and 233 degrees.
supercardioid microphones come with unique features like the rear lobe of sensitivity, sound isolation, and many more. The supercardioid polar pattern is best for use in films due to its high directionality.
The supercardioid polar pattern is similar to the hypercardioid polar pattern. Both are more directional than the standard cardioid pattern, and they are known for their rear lobe of sensitivity.
Acceptance angle is the angle that drops by 3dB before sensitivity. The supercardioid polar pattern has a tighter acceptance angle of 150 degrees, whereas the cardioid polar pattern has an angle of 180 degrees. Our article titled What is a Cardioid Microphone? may be a useful read also.
The reduced rear lobe of sensitivity is a unique characteristic of supercardioid microphones; it clearly says there will not be over the defined sound coming from the rear of the mic. However, it is important to know that this lobe is also present.
You should never point a supercardioid mic in such a position that its rear lobe points are towards the live monitor; it is feedback.
As the supercardioid polar pattern has a rear lobe of sensitivity, they also have null points.
Supercardioid Microphone Features
Supercardioid microphones have nearly the same features as hypercardioid microphones. The following are the features of supercardioid microphones.
A popular base polar pattern for Shotgun Microphones
Almost all shotgun microphones have supercardioid or hypercardioid polar patterns. Such mics are highly directional; they use interference tubes to narrow down the acceptance angle in front of the pattern.
Shotgun microphones are popular in films and broadcasts, and they are usually found at the end of boom poles that are placed above the actors’ heads. Also, due to their directional feature, mics are placed on the top of the camera to offer a narrow pick-up to catch the camera frame.
Shotgun mics are unidirectional mics that generally have small sides and a rear lobe of sensitivity.
A good choice for close miking
Supercardioid mics are a good choice for films, live recordings, and close mic situations in noisy environments. Such mics are popular for recording nearby instruments or other sound sources in noisy or louder environments. Remember that when positioning a supercardioid mic, rear lobe sensitivity is essential for isolated sounds.
Null points at 127 and 233 degrees
If you look at the graph of supercardioid polar pattern, you may notice that supercardioid mics have null points at 127 degrees and the other side of it on the axis at 233 degrees.
Theoretically, null points in microphones are the directions where mics do not pick up the sound. In reality, it depicts the sound as significantly attenuated at higher frequencies. The sound sources, acoustics, and reflections enable sounds to enter the diaphragm from other directions even if they directly come from the null point’s direction. The null points block the particular sound from the direction.
Rear cone of silence
With the null points at 127 and 233 degrees, supercardioid mics have a maximum level of sound rejection at such angles in 2D. In 3D, this is known as the rear cone of silence. This cone of silence is important because mics are almost always used in 3D spaces. Understanding the rear cone of silence and the rear lobe of sensitivity helps with positioning and optimizing supercardioid microphones correctly.
Rear lobe of sensitivity is produced -10dB at 180 degrees
The ideal supercardioid polar pattern’s rear lobe is prominent, but at -10 dB, it is relative to on-axis sensitivity and is not present at the mic signal. It is essential to be aware of the rear lobe of sensitivity of a supercardioid polar pattern.
When the rear lobe is -10 dB, less sensitivity as per on-axis sensitivity makes it a better choice when positioning supercardioid microphones. The rear lobe usually changes along with the frequency response of a microphone. An ideal supercardioid polar pattern has 10 dB sensitivity between 0 to 180-degree lobe sensitivity.
Sides are less sensitive at 10dB
Supercardioid microphones are well known for their high directionality, so they reject sounds from the sides. This is the main reason why supercardioid mics are great for isolating sound sources.
Remember that 10 dB is ideal for supercardioid polar patterns. In a perfect supercardioid polar pattern, you will get 10dB of attenuation at the sides of 90 and 270 degrees. When the polar pattern is at lower frequencies, the side attenuation is likely to be less than 10 dB and vice versa; the attenuation is greater than 10 dB at higher frequencies.
Offers proximity effect
Both sides of the diaphragm of supercardioid mics are well exposed to external sources. The supercardioid polar pattern works on the pressure-gradient principle and provides a proximity effect.
The proximity response increases the bass response as the directional polar pattern gets closer to the sound source. The complete principle is based on amplitude and the difference between all diaphragm slides.
The slight differences between phases are usually found with low frequencies, and with an increase in the amplitude, the difference shortens the difference between sound source and microphone.
A supercardioid polar pattern is sensitive to vocal plosives
Vocal plosives are air noises produced primarily with words that start with the letter “P”. Usually, vocal plosives have the capability of overloading the mics because of their transient nature.
A vocal plosive produces a good amount of pressure on either side of the supercardioid polar pattern diaphragm, which further creates suction power on the other side. It results in fast overloading of the polar pattern, and that gives a “pop” sound. Because of the pressure gradient principle, a supercardioid polar pattern is sensitive to vocal plosives.
Offers great sound isolation
A supercardioid polar pattern has a narrow and unidirectional pattern compared to other cardioid mics, and they are more effective for isolating sound. Such a feature allows a mic to be an excellent choice for recording a single sound source in isolation.
Sound isolation is one of the primary features of a supercardioid microphone.
Ideal for single recording source
Supercardioid mics are a perfect mic for recording a single source due to their isolated sound source feature and directionality. As a result, they are great for live recording sessions, broadcasts, or studios for recording a single sound source, no matter if the background is noisy.
High gain before feedback
Usually, what we hear about feedback is an unpleasant sound of a microphone projected by loudspeakers in a live event. Microphone feedback is a loop between a microphone and a loudspeaker. Loudspeakers amplify the microphone’s signals, and then the mic picks up the sound from the loudspeaker.
It overloads the system when such a positive loop continues, resulting in poor loudspeaker to mic feedback. To eliminate the mic feedback, position the mic in such a place where loudspeakers are 127 and 233 degrees off-axis.
More directional at higher frequencies
Supercardioid mics become more directional at higher frequencies. The polar pattern of supercardioid tends to be more directional than the lobar polar pattern, likely at higher frequencies.
Less directional at lower frequencies
Vice versa to the above point, supercardioid polar pattern mics become less directional when they are at lower frequencies. This means a transition to a cardioid polar pattern at a lower level of frequency response.
Pressure gradient principle
The main feature of a supercardioid polar pattern is that they work on the pressure gradient formula. A pressure gradient principle is present in all directional polar pattern mics. It states that such mics have both sides open to sound waves.
Both sides of a supercardioid diaphragm are exposed to the environment, and they react to sound waves. The pressure difference between the two sides causes a diaphragm to move, and it coincidentally gives an output mic signal.
A polar pattern is achieved with an acoustic labyrinth that covers the rear of the diaphragm
Supercardioid microphones work on the pressure gradient principle, which requires an acoustic labyrinth to manipulate sound phases before the sound reaches the rear of the diaphragm. When the acoustic labyrinths are crafted carefully, they are well used to offset the timings of sound waves at the rear of the mic. This is a practical part of achieving a supercardioid polar pattern.
5:3 ratio of omnidirectional and bidirectional polar pattern
Suppose a cardioid polar pattern is at 1:1 superposition of an omnidirectional and bidirectional polar pattern. In that case, you can imagine a 5:3 ratio of the omnidirectional and bidirectional polar pattern in a supercardioid microphone.
How Can We Achieve a Supercardioid Polar Pattern?
Achieving a supercardioid polar pattern is similar to achieving a cardioid polar pattern. The polar pattern is performed by a specific calculation of the rear acoustic labyrinth responsible for offsetting the timing of sound waves that are liable to hit the rear of the diaphragm.
It is essential to understand that a microphone diaphragm experiences the same sound pressure on both front and rear sides of a mic; they cannot move. If a particular sound wave happens to hit both sides of the diaphragm at once, they will cancel the sound itself, and it causes a null point or absence of mic signal.
Keeping this in mind, a supercardioid polar pattern works on a pressure gradient principle where the front side of the polar pattern is fully exposed to external sound sources. The rear side of the diaphragm has a carefully made acoustic labyrinth. An acoustic labyrinth is responsible for offset timings of sound sources that pass through it, which further delays reaching the sound waves to the rear of the diaphragm.
With this said, a supercardioid polar pattern null points are ideal at 127 and 233 degrees from the on-axis. The sound sources are at 127 and 233-degree null points; they hit the acoustic labyrinth and take time to reach the rear of the mic.
When reaching sound waves on the front side, it takes enough time from the same point. The sound waves cancel themselves, which creates null points in a supercardioid polar pattern. To reach the null points, the supercardioid polar pattern exhibits the rear lobe of sensitivity.
Sound sources that come directly from the rear mic hit the diaphragm before it reaches the front of the mic. It will result in diaphragm movement.
A rear lobe of a supercardioid polar pattern has been attenuated because of phase differences. The rear lobe is 10 dB at 180 degrees compared to on-axis pick up at 0 degrees.
The Supercardioid Polar Pattern Option in Multi-pattern Microphones
Most multi-pattern microphones come with a dual membrane capsule with a back to back diaphragm with different cardioid polar patterns. When a supercardioid polar pattern is used in multi-pattern microphones, it is achieved by mixing two mic signals. The first signal is mixed with positive polarity and greater amplitude, and the rear diaphragm signal is negative polarity and has less amplitude.
Where Can You Use a Supercardioid Microphone?
Every polar pattern comes with many pros and cons, and a supercardioid microphone is no exception. It is best for some circumstances and whereas it may not be as good in others. Here are some cases where you can use a supercardioid microphone:
- It is best used as an end boom pole in the film industry.
- The supercardioid microphone is mounted on the cameras to reject off-sound waves.
- It is mostly used in dual foldback monitors or loudspeakers in live recording sessions.
- The supercardioid polar pattern performs well in a narrow acceptance angle and directional pick-up sounds.
- Good choice for recording single sound sources in noisy environments.
- It is well used to record closely placed sound sources like drum sound waves from a drum kit.
Here are some cases where supercardioid microphones should not be used:
- Do not use supercardioid microphones for recording natural sound environments or ambiance.
- Do not use the mic as a stationary mic for moving targets.
- Never place a supercardioid microphone in front of foldback monitors during a live performance.
Supercardioid Mic Techniques
Here is a list of miking techniques that you can use with the help of a supercardioid polar pattern:
Close miking is placing a mic close to a sound source, especially when there are other sound sources present in the environment. Close miking is responsible for improving the isolation feature by decreasing bleed and room sound. This supercardioid miking technique is important for adding clarity and flexibility while mixing the sound sources. Close supercardioid mics are usually placed within 2 feet from their sound sources.
Olsen Stereo 180 Microphone Technique
This is a common stereo miking technique where two or three microphones are placed to catch the stereo image of an acoustic sound. Such a technique is usually kept simple by placing two mics left and right. The Olsen stereo 180 technique comes with two hypercardioid mics placed at an angle of 135 degrees. This technique offers a wide image of sound sources.
The OCT Hamasaki is a popular miking technique that is well known as the surround sound miking technique. A surround sound miking technique uses a common optimized cardioid front array and Hamasaki surround array. The optimized cardioid triangle front array technique uses three mics in a triangle, and Hamasaki sound array technique has four bidirectional mics placed at 2 meters away. The mic points to the left and right sides so that the null points can face the sound source. The Hamasaki sound array technique catches ambient sound sources. The OCT Hamasaki uses one cardioid, two hypercardioid, and four bidirectional microphones and has a capacity of the span of four meters deep and three meters wide.
The OCR IRT is a popular sound surround miking technique that uses an optimized cardioid triangle front array and IRT surround array technique. This miking technique is popular because it uses five cardioid and two hypercardioid microphones and can span 133 cm deep and 100 cm wide.
This sound surround miking technique uses an OCT front array mic with two rear mics. Here, two mics are placed on the front cardioid mic, and ahead of it is a supercardioid mic.
Other Polar Patterns
Along with the supercardioid polar pattern, there are many other microphones available in the market. The following are the different microphone polar patterns:
Omnidirectional Polar Pattern
These mics are good at picking the sound from every direction equally.
Bidirectional Polar Pattern
When a mic has a bidirectional polar pattern, it picks up the sound symmetrically from the front and the back with equal sensitivity and different popularity. Bidirectional polar patterns have null points at 90 and 270 degrees at sides.
Cardioid Polar Pattern
A popular unidirectional polar pattern is used in cardioid microphones. It has a 180-degree null point at the rear and a 6 dB decrease in sensitivity at the sides of 90 and 270 degrees to the on-axis.
Hypercardioid Polar Pattern
This is roughly the same as a supercardioid polar pattern but with a narrow on-axis response. It has null points at 110 and 250 degrees with a cone of silence. If you’re interested in finding out more about Hypercardioid mics, we’ve answered the question here What Is a Hypercardioid Microphone?
Sub-Cardioid Polar Pattern
A unidirectional polar pattern with a wider response is known as a sub-cardioid polar pattern. It looks like a midway between cardioid and omnidirectional polar patterns. Talking of omnidirectional, we’ve also covered this in depth in our What Is an Omnidirectional Microphone article.
When considering a supercardioid microphone to buy, it is important to understand the features and technical details of the pickup pattern, as well as the pros and cons with its usage. We hope the information we have provided in this article will be useful in helping you understand supercardioid microphones better.
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