How other speakers work:

<1> Magnetic speaker: also known as "reed speaker", there is an electromagnet with a movable iron core between the two poles of the permanent magnet. When there is no current in the coil of the electromagnet, the movable iron core is attracted by the two magnetic poles of the permanent magnet. The movable iron core remains stationary in the center due to the attraction of force; when current flows through the coil, the movable iron core is magnetized and becomes a strip magnet. As the direction of the current changes, the polarity of the bar magnet also changes accordingly, causing the movable iron core to rotate around the fulcrum. The vibration of the movable iron core is transmitted from the cantilever to the diaphragm (paper cone) to promote thermal vibration of the air.
<2> Electrostatic speaker: It is a speaker that uses electrostatic force added to the capacitor plate to work. In terms of its structure, because the positive and negative electrodes face each other to form a capacitor shape, it is also called a capacitor speaker. There are two thick and hard materials as fixed plates, which can transmit sound, and the middle plate is made of thin and light material as the diaphragm (such as aluminum film). Fix and tighten around the diaphragm to keep a considerable distance from the fixed pole. Even on a large diaphragm, it will not collide with the fixed pole.
There is a DC voltage (called bias voltage) between the two electrodes. If the audio voltage output by the amplifier is added between the two electrodes, it will overlap with the original output voltage to form an alternating pulsating voltage. This pulsating voltage is generated by the change in the strength of the attraction between the two electrodes, and the diaphragm vibrates and produces sound.
The advantage of the electrostatic speaker is that the entire diaphragm vibrates in phase, the diaphragm is light, and the distortion is small. It can reproduce excellent sound, has good resolution, good detail restoration, and realistic sound. Its disadvantages are low efficiency, requiring a high-voltage DC power supply, easy to absorb dust, and the larger the diaphragm, the greater the distortion. It is not suitable for listening to rock and heavy metal music, and the price is relatively expensive.