Moving coil

The basic principle comes from Fleming's law of the left hand. When a current wire is placed vertically between the north and south poles of a magnet, the wire will be moved by the interaction between the magnetic force line and the current. When a diaphragm is attached to this wire, the diaphragm will move forward and backward as the current changes. At present, more than 90 percent of cone monomers are movable coil designs.

electromagnetic

A movable cut iron plate (armature) is placed in the middle of a U-shaped magnet. When the current flows through the coil, the armature is magnetized and the magnet is repulsed, simultaneously driving the diaphragm to move. The design is cheap but ineffective, so it is often used in microphones and small earphones.

inductive

Similar to electromagnetic, but with double armatures, the two coils on the magnet are not symmetrical, and the two armatures push against each other for different magnetic fluxes as the signal current passes through. Unlike electromagnetism, inductance is able to regenerate lower frequencies, but the efficiency is very low.

electrostatic

The basic principle is Coulomb's law, usually a plastic diaphragm with aluminum and other inductive materials vacuum vaporization treatment, two diaphragms placed face to face, when one of the positive current high voltage when the other will induction of a small current, by mutual attraction and repulsion to promote the air can emit sound. Electrostatic monomer due to light quality and small vibration dispersion, so it is easy to get clear and transparent high pitch, bass power has not captured, and its efficiency is not high, the use of DIRECT current and easy to gather dust. At present, manufacturers such as Martin-Logan have successfully developed hybrid speakers of static and moving coil, which solves the problem of insufficient bass of static body, and is also widely used in earphones.

A flat

The earliest design developed by SONY in Japan, voice coil design is still moving coil type as the theme, but the cone cone diaphragm is changed to the plane diaphragm of honeycomb structure, because of fewer cavity effect, better characteristics, but low efficiency.

Ribbon type

Instead of a traditional voice coil design, the diaphragm is made of very thin metal and the current flows directly into the channel body to make it vibrate. Because its diaphragm is the voice coil, it is very light, has good transient response, and high frequency response. However, the efficiency and low impedance of the ribbon horn have been a major challenge for the amplifier, as exemplifies the Apogee. Another way is to have a voice coil, but to print the voice coil directly on a plastic sheet, which solves some of the low impedance problems, and Magnepang is a leader in such designs.

Horn type

Diaphragm to push in the trumpet at the bottom of the air and work, because the sound transmission is not spread so efficiency is very high, but because of the horn shape and length will affect the sound, to replay low frequency is not too easy, now mostly use on the giant PA system or high monomer, Klipsch America is the old font size of horn speaker manufacturers.

other

Then there is the improved ribbon design developed by Dr. Heil in 1973, called the Heil Trumpet, which is excellent in theory but has few Taiwanese users. Pioneer has adapted the piezoelectric design, which uses a piezoelectric material such as Titanic acid to stretch or contract when applied with a voltage, for their treble monomers. Ion horn (Ion) uses high voltage discharge to make the air become charged. After applying ac voltage, these free charged molecules will sound due to vibration. Currently, it can only be used in monomer above high frequency. Philips has also developed the active feedback loudspeaker (MFB), which has an active feedback circuit inside the loudspeaker to reduce distortion significantly.