1. Common heart shape (super heart shape)
This kind of directivity means that the most sensitive recording on the front is the loudest. The least sensitive recording sound on the back.
Its directional map seems to be similar to the human heart. The cardioid microphone is unidirectional, which means that the front of the microphone must be used to pick up the sound source, and the sensitivity of the back is much lower.
This feature is suitable for keeping the picked up sound source isolated from other stage sounds. Many large-diaphragm condenser microphones have this directivity.
The cardioid directional microphone has a close-talking feature-the mid and low frequencies are improved when you are close to the microphone.
2. Figure 8
This is the most sensitive on the front and back, the left and right sides are the least sensitive
Both sides have the same sensitivity, and have a good isolation effect for the sound that is 90 degrees off the axis
This kind of directional microphone has the same sensitivity in the front and back directions of the diaphragm, and has a strong isolation to the side sound.
The close-talk effect of a figure-eight microphone is similar to that of a cardioid.
A figure-eight microphone picks up duets and face-to-face interviews are particularly good. The side sensitivity of -40dB is very useful for isolation between musical instruments. Figure 8 microphone is the key part of M/S (mid-side) stereo pickup.
It’s very sensitive in all directions and generally used to record ambient sounds
Omnidirectional microphones have the same sensitivity and frequency response for sounds from all directions.
Compared with the cardioid microphone, the sound field picked up by the omnidirectional microphone is wider, which is especially suitable for recording chorus, environmental sound effects, and acoustic instruments because it has a particularly good sense of space
Another important feature of the omnidirectional microphone is that it has less close-talking effect compared to the cardioid microphone, which has the advantage of being insensitive to the slight movement of the sound source.
Another feature of omnidirectional is that it does not require much equalization. These early theoretical data, however, when the sound source of the 360-degree sound source is picked up by the omnidirectional microphone, it is impossible to achieve the same. The actual situation is that there must be a little recessed state behind the microphone head, and the frequency response will not be very the same. As the diaphragm increases, this point becomes more prominent.
Fourth, super cardioid pointing
Its directivity is stronger than the heart shape, and it has a "tail" on the back
The directivity of the super cardioid microphone is narrower than that of the cardioid, which is especially suitable for close-range pickup.
It is particularly suitable for fixed-point recording of drums and pianos, and its directional characteristics are very suitable for on-site recordings that require isolation (sometimes to isolate interference between instruments, and sometimes to isolate noise).
For self-playing and self-singing performance recordings, the mutual crosstalk of super-directional microphones is minimal.
Five, single-pointing VS multi-pointing
The production cost of unidirectional microphones is lower than that of multi-directional microphones.
Cardioid microphones generally obtain single-sided directivity by opening a hole on the back plate of the diaphragm, which is a solid pointing design.
The omnidirectionality is obtained through a sealed back plate.
The super-cardioid microphone achieves multi-direction through two back-to-back diaphragms and corresponding circuits.
Some microphones use replaceable microphone head technology to obtain multiple directivity, which saves a lot of money than buying several microphones separately.
There is another way to make a condenser microphone multi-directional.
The two cardioid poles are placed back to back and combined with a variety of circuits to obtain multiple directions.
The omnidirectional is obtained by combining two cardioid poles with a positive phase circuit,
Two cardioid poles combined with an inverting circuit can get a figure-eight orientation. By adjusting the polarity and output level of the two poles, the supercardioid orientation is obtained.