How many types of headphones?

According to the principle of headphone sound, can be divided into piezoelectric headphones, moving iron headphones, moving coil headphones, electrostatic headphones, pneumatic headphones. Detailed differences are as follows:

1. Piezoelectric headphones: use the piezoelectric effect of piezoelectric ceramics to generate sound. High efficiency, high frequency. Disadvantages: distortion, high drive voltage, low-frequency response is poor, poor impact resistance. Such headphones are mostly used for telegraph transceiver use, now basically eliminated. A few headphones using piezoelectric ceramics as a tweeter.

2. Moving iron headphones: the use of electromagnets to generate alternating magnetic fields, vibration part is a piece of iron suspended in front of the electromagnet, the signal will make the electromagnet magnetic field changes when passing through the electromagnet so that the iron vibration sound. Advantages are long service life and high efficiency. The disadvantage is that the distortion is large, the frequency response is narrow. Commonly used in the early telephone handset.

3. Moving coil headphones: This is now the most common form of headphones. The coil is fixed on the diaphragm, placed in a fixed magnetic field generated by a permanent magnet, the signal through the coil cutting the magnetic lines, which drives the diaphragm to vibrate together to make sound. The advantage is relatively easy to produce, good linearity, low distortion, wide frequency response. The disadvantage is low efficiency.

4. Electrostatic headphones: also known as electrostatic plane diaphragm, is the aluminum (or other conductive metal) coil directly plated or printed on a very thin plastic film, it will be placed in a strong electrostatic field, the signal through the coil when cutting the electric field, driving the diaphragm vibration sound. Advantages are good linearity, distortion is small, good transient response, the high-frequency response is good. The disadvantage is that the low-frequency response is not good, needs special drive circuit and electrostatic generator, and is expensive. Efficiency is also not high.

5. Pneumatic headphones: the use of air pumps and valves to control airflow, direct control of air pressure and flow, making the air vibration. Sometimes the air valve is replaced by a high-powered speaker. Aircraft commonly used in such a headset, this headset is actually just a guide tube. Advantages are no electrical drive, unlimited parallel connection, high efficiency. The disadvantage is that the distortion is large, narrow frequency r