Microphone

A microphone is both a microphone and a transducer. It is a tool for converting sound (one kind of energy) into electrical signals (another kind of energy).

I. Type of microphone
According to the working principle, our common microphones are mainly divided into three categories: dynamic microphone, condenser microphone and ribbon microphone.

1. Dynamic microphone features:
Advantage:
The structure of the dynamic microphone is very simple and the manufacturing cost is low, so its price is relatively cheap.
② Dynamic microphone sensitivity is relatively low, so the requirements for the recording environment are not high, even in a noisy environment, it can record a relatively clean sound. Not easy to pop and not easy to howl, it is very suitable for KTV, concerts and other occasions.
Dynamic microphone is very durable, almost not affected by temperature and humidity, resistant to falling, resistant to bumping, and can be used for decades.

Disadvantage:
Lower sensitivity brings benefits as well as drawbacks to recording. The sound recorded by dynamic microphone lacks sound details, is dull, thick and low, which is the style of radio broadcasting.

2. Features of condenser microphone:
Condenser microphones can be subdivided into electret microphones, that is, earphone microphones, small bees (collar microphone), gun microphones, and large diaphragm/small diaphragm condenser microphones used in recording studios. Electret microphone is widely used, which has the characteristics of high sensitivity, good stability, small size, light weight and good shock resistance.

Advantage:
The sensitivity is very high, it can pick up rich sound details, the sound quality is exquisite, and the sound restoration is better. It is suitable for friends who pursue high sound quality.

Disadvantage:
① Also because of the high sensitivity, this kind of microphone has a particularly high requirement for the recording environment, and a little sound will be recorded, so if the recording environment is noisy, it is not recommended to enter.
② Compared with the dynamic microphone, the large diaphragm/small diaphragm condenser microphone is very delicate and easy to be damaged due to improper use. It is necessary to pay attention to moisture-proof, dust-proof and other maintenance work. It is best to equip a moisture-proof box (how to choose a moisture-proof box) for storage.

3. Features of ribbon microphone:
Ribbon microphones are not common or used much, and are an old professional microphone.

Advantage:
The timbre is warm and retro, the frequency response is straight, the transient state is good, and the sound reduction degree is high.

Disadvantage:
① The workmanship is complex and the price is expensive.
② More delicate than the condenser microphone, afraid of moisture, wind and vibration, especially easy to damage.

II. Main parameters of microphone
1. Directivity, in fact, is an effective range for the microphone to pick up sound. It is mainly divided into single direction, double direction and full direction.
① Single direction. Include cardioid pointing (about 130 ° directly in front of the microphone), hypercardioid pointing (about 110 ° directly in front of the microphone), and gun pointing. Large diaphragm/small diaphragm microphones like those used in recording studios, as well as dynamic and shotgun microphones, are single-pointing.
② Double direction. Also known as figure-eight pointing, the front and rear of the microphone are effective pickup areas, which can play a very good attenuation (generally speaking, it can reduce or even eliminate the volume) for the sound from the side. The ribbon microphone mentioned above is a figure-eight pointing.
③ Omnidirectional. It can also be understood that there is no direction, because it is 360 degrees omnidirectional sound. Like the bee, the headset and the microphone on the mobile phone are all omnidirectional.
2. The response frequency is the frequency range of the microphone. Usually the frequency range that our human ears can hear is 20hz-20khz, which can be used as a reference.
3. The frequency response curve is the sensitivity of the microphone at each frequency point. If the curve is straight, it is better to restore the sound.
4. Own background noise, this dynamic microphone does not have, condenser microphone has, that is, hiss, the smaller the better. 20db down is better.
5. Signal-to-noise ratio is simply a ratio between the sound you need and the noise, the bigger the better. About 60db is better.
6. Sensitivity. The volume emitted under the rated voltage or power is generally the sensitivity at the point of 1 kHz. The higher the value, the better.