Generally speaking, earphones are divided into seven categories: piezoelectric, moving iron, moving coil, electrostatic, pneumatic, etc. magnetic and electret.
Piezoelectric: making sound by using the piezoelectric effect of piezoelectric ceramics. High efficiency and high frequency. Disadvantages: large distortion, high driving voltage, poor low frequency response and poor impact resistance. These earphones are mostly used for telegram sending and receiving, and are now basically eliminated. A few earphones use piezoelectric ceramics as tweeter units.
Moving iron: the electromagnet is used to generate alternating magnetic field. The vibrating part is an iron plate suspended in front of the electromagnet. When the signal passes through the electromagnet, the magnetic field of the electromagnet will change, so that the iron plate vibrates and sounds. The utility model has the advantages of long service life and high efficiency. The disadvantage is large distortion and narrow frequency response. It is often used in the early telephone receiver.
Dynamic: This is now the most common form of headphones. The coil is fixed on the diaphragm and placed in the fixed magnetic field generated by the permanent magnet. The signal cuts the magnetic line of force through the coil, so as to drive the diaphragm to vibrate and sound together. The utility model has the advantages of relatively easy fabrication, good linearity, small distortion and wide frequency response. The disadvantage is low efficiency (not a disadvantage).
Static electricity: also known as electrostatic plane diaphragm, aluminum (or other conductive metal) coil is directly electroplated or printed on a very thin plastic film and placed in a strong electrostatic field (usually composed of DC high voltage generator and fixed metal sheet (net). When the signal passes through the coil, the electric field is cut to drive the diaphragm to vibrate and sound. The advantages are good linearity, small distortion (electric field is more uniform than magnetic field), good transient response (diaphragm weight is light) and good high frequency response. The disadvantages are poor low-frequency response, need special driving circuit and electrostatic generator, and high price. Efficiency is not high.
Pneumatic: air pump and valve are used to control the air flow, directly control the air pressure and flow, and make the air vibrate. Sometimes the air valve is replaced by a high-power loudspeaker. Such earphones are commonly used in aircraft. In fact, this earphone is only an airway. The utility model has the advantages of no electric drive, unlimited parallel connection and high efficiency. The disadvantages are large distortion, narrow frequency response and noise.
Isomagnetic type: the principle of isomagnetic electroacoustic transducer and moving coil electroacoustic transducer is the same, but the structure is different. The equimagnetic electroacoustic transducer uses a plane vibration mode. Multiple groups of voice coil lines are coated on the plane vibration membrane, and there are magnetic circuits corresponding to them. Because the diaphragm is thin and light, and can be fully driven, it has wide frequency band, good high-frequency characteristics and transient characteristics, low distortion, but its sensitivity is lower than that of ordinary moving coil electroacoustic transducer.
Electret: electret electroacoustic transducer is a special electrostatic electroacoustic transducer. Modern technology can make some dielectrics (Electret Materials) remain charged after the external electric field is removed by corona discharge or electron bombardment at high temperature and high pressure. In contrast, we are familiar with the example that some ferromagnetic materials (permanent magnet materials) can retain their magnetism when they are magnetized. We call them permanent magnets. Therefore, electrets are often called "permanent electrics". In fact, either "permanent magnet" or "permanent electricity", but relatively speaking, they will also "lose magnetism" and "lose power" with the change of service time or external conditions. In other words, their performance also has "life". The service life of excellent electret can reach more than 15 years.
I think the current situation of headphones and fever audio is somewhat similar. They can be roughly divided into European sound and American sound, or monitoring type and music type,
There are many monitoring earphones produced in European countries. They are characterized by a slight lack of low-frequency components, very balanced in other frequency bands, less sound pollution, faithful, reserved, transparent and cold. They are close to the sound characteristics of professional monitoring earphones. Suitable for classical and symphonic music.
The representative products of music earphones are Koss, Goethe and Alice. This kind of earphone fully reflects that Americans are pragmatic and informal. For the purpose of satisfying the sense of listening, they modify and polish the sound, do not overemphasize the authenticity of the sound, the sound is thick and warm, the bass is relatively strong, the sense of rhythm is strong, and the sound is full of sensibility and musicality. It is suitable for various types of music, especially light music, modern music and pop music.
The music performance characteristics and suitable music types of the above two headphones are not absolute, but they have their own emphases.
At the same time, the earphones produced in the United States are not entirely the type of American sound. For example, the Intemet earplugs have a strong monitoring style. There is also Koss monitor headset pro4aa, which is also a very authentic monitor headset, no less than the top monitor headset.
It should also be pointed out that no matter what style of headphones, their high-end products and advanced models are very faithful to the performance of music, and there is no obvious sound pollution, but they all maintain their own styles.
In addition, the representative brands of Japanese earphones are iron triangle and Sony. Most of the low-end earphones of these two brands are produced in China, including Taiwan and Southeast Asia.
The sound characteristics of Japanese earphones are different from the above two types. Human voice is the characteristic of this kind of earphone, with warm sound and appropriate modification. Of course, his professional monitoring headset is another case, which is a genuine monitoring tone
When someone mentions modification, it is associated with distortion. In fact, modification should modify and polish the sound signal in every audio equipment and every link. Even European headphones are modified, because the timbre of different European brands is not exactly the same. The key is whether the modification is appropriate.
