The sound heads currently on the market mainly include: moving coil type, capacitive type, electret and the newly released silicon micro.
Moving coil type: The diaphragm is vibrated by the human voice through the air, and then the coil winding on the diaphragm and the magnet surrounding the moving coil sound head form a magnetic field cutting, forming a weak current.
Capacitive: Using the principle of capacitive charging and discharging between conductors, ultra-thin metal or gold-plated plastic film is used as a vibrating film to induce sound pressure, which changes the static voltage between conductors and directly converts them into electrical energy signals, and obtains practical output through electronic circuit coupling Impedance and sensitivity are designed.
Electret type: The diaphragm is vibrated through the air with human voice, so that the distance between the upper diaphragm and the lower metal iron sheet changes, and the capacitance changes to form current impedance.
To distinguish from the directivity of the microphone, there are mainly omnidirectionality, figure 8 directivity and cardioid directivity.
The polar coordinates of various pointing microphones are shown below:
It can be seen that the cardioid and super-cardioid directional microphones have the highest sensitivity to sound waves incident directly in front of the diaphragm, and the lowest sensitivity to sound waves incident directly behind the diaphragm. In KTV and performance situations such noisy environments Medium is very suitable. So, what is the difference between cardioid and super cardioid directional microphones in specific use?
The pickup range of a cardioid directional microphone is like a heart: in front of the microphone, its sensitivity to audio signals is very high; on the side of the microphone (at 90 degrees), its sensitivity is also good, but it is more The front should be 6 decibels lower; finally, it has a very good shielding effect for the sound from the back of the microphone. It is also the type of microphone most often encountered by singers. It is often described as having a heart-shaped pattern and is usually used in studio recording of human voices. When you don’t want to pick up the audience’s voice or the sound from your monitor, the cardioid microphone is very suitable in this case (when using a cardioid microphone, the monitor should be placed opposite you, 180 degrees from you ). In the studio, the use of cardioid microphones can effectively reduce the surround sound and the sound reflected by the microphone. This can help you record in undesirable environments, or reduce the sound of other music around you.
It is precisely because of this shielding effect on the sound behind the microphone that the cardioid pointing microphone is very useful in multiple recording environments, especially when a large amount of indoor ambient sound needs to be eliminated. In addition, this microphone can also be used for live performances, because its shielding function can cut off the echo and environmental noise generated during the performance. In practice, cardioid microphones are also one of the most frequently used microphones, but remember that like all non-omnidirectional microphones, cardioid microphones will also show a very obvious proximity effect[ 1].
The super cardioid microphone is very similar to the cardioid, and is often confused. The general cardioid type has a slightly worse directivity than the super cardioid, and its sensitivity to the sound from the back of the microphone is much smaller. Its directivity is stronger than that of 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. Pick up close-up sounds more accurately, and eliminate most of the interfering noise in the scene. The supercardioid curve is more directional than the cardioid curve, which cancels out more sound from the side of the microphone. When pointing to a sound source, the interfering sound (off-axis) can be well suppressed.