Polar patterns are often misunderstood by some who are not too conversant with them. So, what are polar patterns?
The polar pattern of a microphone defines how it responds to sounds as they come from different directions. These polar patterns show how the position of a microphone can be used to maximize the pickup of sounds from the desired source of the sound, and at the same time, minimizing the pickup or feedback of unwanted sounds, as they come from inadvertent sources.
Polar patterns of microphones can also be described as their sensitivity to various sound sources relative to the angle or direction from where the sound is coming. In simpler terms, it may be expressed as to how the microphone “hears” sound from the different direction of projections. The most common of the types of directionality are as follows: Cardioid, omnidirectional, and supercardioid.
Supercardioid Polar Pattern
A supercardioid polar pattern microphone has a narrower or tighter pickup angle than a cardioid pattern, however, unlike the cardioid, it provides even a greater side or lateral rejection. But in this, it is somewhat sensitive to the sound sources directly behind the microphone. A supercardioid microphone provides better isolation from ambient or room noise and the nearby instruments. It can also be more resistant to feedbacks than cardioid microphones. However, for this to work well, the user must maintain a more consistent position which should be directly in front of the microphone.
For independent filmmakers, supercardioid microphones are one of the most popular types of microphones they use. And this is because these microphones help to isolate desired audio while allowing for a low error rate. The supercardioid pattern is majorly found in shotgun microphones mounted on a video camera or used on boom poles. Note that supercardioid microphones may also pick up some sound coming from behind the microphone. Therefore, when you mount a supercardioid microphone to your camera, you should minimize the operating noise, as much as possible.
What can I use a supercardioid microphone for?
Narrow recording pickup
Supercardioid microphones provide a narrower recording pickup than cardioid microphones. It also provides a stronger rejection of ambient noise. However, they may also pick up some sounds from directly behind the microphone. Consequently, it is important to properly position the monitor speakers.
Good for noisy environments
Supercardioids are best when you want to collect individual sound sources in noisy environments. These types of microphones are resilient in their resistance to feedback.
They are useful in inevitably noisy environments when there is a need to isolate and pick a voice or instrument while the ambient noise is minimized. They are used by spies or eavesdroppers to listen to secret or distant conversations. To make it more directional, using a parabolic dish directed towards the microphone, can sometimes make all the difference. These types of microphones are rarely used in the studios. It is probably the most used in sports broadcasting where there is a need to get sound from the team on the field, especially if you cannot get a microphone nearer to them.
Best applications for supercardioid microphones
- Placed at the end of a boom pole (for film).
- Mounted on a camera to better suppress off-frame noise/sounds.
- Placed in front of a dual foldable monitor in a live sound reinforcement situation (at the null point).
- Used for directional pickup and a narrow acceptance angle.
- Close miking/isolating of individual sound sources in noisy environments.
- For pick-up of individually positioned sound sources. e.g. drums in a drum kit.
Pros of using supercardioid microphones
- Excellent sound isolation
- It is a relatively unidirectional and narrow pattern, and this makes the supercardioid microphone able to effectively isolate unwanted sounds from unwanted sources.
- The excellent isolation affects the next point which shows the supercardioid microphone is ideal for capturing individual sound sources.
- Ideal if you need to capture sound from a single character.
- Thanks to the excellent directionality and isolation of the supercardioid microphone, you can excellently capture one sound source. This applies to studio, broadcast or radio, and on a live stage environment, it doesn’t matter whether it is quiet or noisy.
- There is high gain before feedback
- Due to the directional effect and the null point of the polar pattern, supercardioid microphones have significant gain before feedback.
Cons of using a supercardioid microphones
- Becomes more directional at higher frequencies
- Generally, at high frequencies, any microphone gets more directional. This is due to the nature of sound as well as the shorter wavelengths of high-frequency sound waves.
- Polar patterns of the supercardioid microphones often become hypercardioid or even more lobar at higher frequencies.
- At low frequencies, it is less directional.
As with the previous point, microphones are often less directional at lower frequencies. For the supercardioid microphones, this may mean there will be a transition to a cardioid or subcardioid polar pattern at the lower end of their frequency response. It works according to the principle of the pressure gradient.
It should be noted again that the supercardioid microphones (and all directional microphones) operate on the principle of the pressure gradient.
It just means that both sides of the diaphragm of a supercardioid microphone are open to external sound pressure. It is the pressure difference between the two sides of the diaphragm that causes the diaphragm to move and a corresponding output microphone signal is made.