Moving coil
The basic principle comes from Fleming's law of the left hand. Putting an electric wire perpendicular to the magnetic field line between the north and south poles of the magnet, the wire will be moved by the interaction of the magnetic field line and the electric current. When a piece of diaphragm is attached to the track line, the diaphragm will move around as the current changes. At present, over ninety percent of the cone basin monomers are all moving coil designs.
Electromagnetic
A movable chopper (armature) is set up in the middle of a U-shaped magnet. When the current flows through the coil, the armature will be magnetized and the magnet will absorb and repulse the phenomenon, and at the same time drive the vibration film movement. This design is cheap, but it doesn't work well, so it is mostly used in telephone boxes and small earphones.
Inductive
Similar to the electromagnetic principle, but the armature doubles, and the two voice coils on the magnet are asymmetrical. When the signal current passes, the two armature will push each other for different magnetic flux. Unlike electromagnetic, inductance can regenerate lower frequencies, but efficiency is very low.
Electrostatic
The basic principle is Coulomb's law, which is usually treated by vacuum vaporization of plastic diaphragms with inductive materials such as aluminum. Two diaphragms are placed face to face. When one of the diaphragms is applied with positive current and high voltage, the other one will induce a small current, and the air will make sound by attracting and repelling each other. Because of its light weight and small vibration dispersion, electrostatic monomers are easy to get clear and transparent tenor, have no grasp of bass power, and its efficiency is not high, and it is easy to collect dust using DC electrodes. At present, manufacturers such as Martin-Logan have successfully developed electrostatic and coil hybrid horns to solve the problem of electrostatic low-pitch, electrostatic headphones are also widely used.
Planar
The voice coil design, which was developed by SONY in Japan, is still a moving coil design. However, the cone basin diaphragm is replaced by the plane diaphragm of the honeycomb structure, because of the less void effect, the characteristics are better, but the efficiency is also lower.
Ribbon
Without the traditional voice coil design, the diaphragm is made of thin metal, and the current flows directly into the passage to make it vibrate. Because its diaphragm is voice coil, it has light weight, good transient response and high frequency response. However, the efficiency and low impedance of the ribbon horn have been a great challenge to the amplifier, Apogee can be representative. Another way is to have a voice coil, but to print it directly on a plastic sheet can solve some of the problems of low impedance. Magnepang is a leader in this kind of design.
Horn type
The diaphragm drives the air at the bottom of the horn, which is efficient because the sound is not diffused, but because the shape and length of the horn affect the timbre, it is not easy to repeat low frequencies, and is now mostly used in giant PA systems or high-pitch monomers.
Other
There is also a ribbon-type improved design developed by Dr. Haier in 1973, called Haier horn, which is rarely used in Taiwan. Piezoelectric is a design that uses piezoelectric materials such as Titanic acid, plus voltage to make them stretch or shrink to produce sound. Pioneer used high polymer modified piezoelectric designs for their treble monomers. Ion horn (Ion) uses high voltage discharge to make the air become a charged mass, after the application of alternating current voltage, these free charged molecules will vibrate and sound, currently can only be used in high-frequency monomers above. Philips has also developed active feedback horns (MFBs), which are equipped with active feedback circuits that can significantly reduce distortion.