This article focuses on omnidirectional pickups and directional microphones, as well as the knowledge of microphones.
1. The definition of microphone
The microphone is an acoustic-electric conversion device (also called a transducer or sensor), which is the opposite of a horn (electric → acoustic). It is the two terminals of the sound equipment, the microphone is the input, and the speaker is the output. Microphones are also known as microphones, microphones, microphones, microphones, etc.
Second, the classification of microphones
1. From the working principle, it is divided into: carbon granular electromagnetic type capacitive electret capacitive type (the following introduction is mainly electret type) piezoelectric crystal type, piezoelectric ceramic type silica type, etc.
2. According to the size, the electret type can be divided into several types. Φ9.7 series products Φ8 series products Φ6 series products Φ4.5 series products Φ4 series products Φ3 series products have different heights in each series
3. From the directionality of the microphone head, it can be divided into omnidirectional, one-way, and two-way (also known as noise reduction type)
4. From the polarization method, the diaphragm type, back pole type, and front pole type can be divided into grid spot welding type, grid crimping type, pole ring connection type, etc.
5. From the external connection method, it can be divided into ordinary solder joint type: L type with PIN foot type: P type concentric circle type: S type
3. Introduction to omnidirectional pickups and unidirectional pickups
Omnidirectional (OmnidirecTIonal) for sounds from different angles, its sensitivity is basically the same. The microphone head is designed based on the principle of pressure-operated, and the diaphragm only accepts pressure from the outside. It is common in recording projects that need to record the entire environment sound; or when the sound source is moving, and it is hoped to maintain a good sound reception; the lavalier microphone that the speaker wears when giving a speech is also of this type. The disadvantage of omnidirectional is that it is easy to receive noise from the surrounding environment. Single-pointing microphones are mainly designed using the principle of Pressure Gradient. Through the small hole at the back of the microphone cavity, the diaphragm receives the pressure on both sides. Therefore, the diaphragm is not the same in different directions, and the microphone has directivity. And therefore, directional microphones have close-talking effects.
Fourth, the difference between omnidirectional pickup and unidirectional
1. The directional microphone generally has a small pickup radius, 30 cm is a large one. It is used by a single person and placed near the mouth. The sound quality is very good, because no matter how far away it is, it will not pick up the sound. The shape is generally a gooseneck wheat, a rod, a curved rod, pointed to your mouth, directivity, and only listen to your voice. For single-pointing microphones, the sensitivity is limited to a certain range. If the sensitivity is too high, it will cause sharp howling, etc., involving many other equipment.
2. Omnidirectional pickups generally have a large pickup radius, one meter, two meters, three meters, and five meters. Compared with more than ten centimeters, this level is very different. It not only picks up the voice of a person, but Many people, five or six, seven or eight or even a dozen. The sensitivity of omnidirectional pickups is very high, the pickup radius of omnidirectional pickups is too large, and it will also pick up more ambient noise, so the sound quality is not as good as that of unidirectional microphones, unless you do a good job in noise reduction. In terms of processing, Optus Intelligent Sensing Technology (Guangzhou) Co., Ltd. has its own unique 3D noise reduction technology, and the noise reduction effect is currently relatively good. There must be a difference between collective use and single service. But the omnidirectional microphone has an advantage, the wiring is simple, and there is no need to arrange them one by one. It is suitable for some small meetings, ad hoc meetings, some remote discussions, and remote operations.
3. Unidirectional microphones generally support local amplification, and omnidirectional pickups generally do not support local amplification. This should be noted, because of such high sensitivity, the local amplification whistle caused by such high sensitivity is very scary, and the current technology is difficult to deal with. But the long-range echo has already been better handled. The pickups launched by OPPS all have better echo cancellation omnidirectional pickup products.