At present, the vast majority of loudspeakers are still using the traditional cone basin type single body forward and backward motion sound. Academically speaking, these loudspeakers are called electric or moving coil type. As early as 1877, Siemens' Erenst vemer obtained a patent for the moving coil horn. However, the vacuum tube was not officially put into use until 1907. Edison's earliest phonograph was that the stylus directly drove the diaphragm and then amplified the sound through the horn. Therefore, Siemens's patent has never been used.br> 　　In 1920, Chester rice, Edward kerrog and Edison bell P.G. Hokuto of American strange company first developed a practical dynamic horn. In the past more than 70 years, besides the continuous improvement of materials, do you remember the progress of horn technology? The following are several common speaker sound modes collected by manufacturers of headphone speaker accessories:
　　The principle of sound production of earphone horn Part 1: dynamic coil type. The basic principle comes from Fleming's left-handed law. If a current line and a magnetic line of force are vertically placed between the north and south poles of the magnet, the line will move due to the interaction between the magnetic line of force and the current. When a diaphragm is attached to the line, with the change of current, the diaphragm will move forward and backward. At present, more than 90% of the cone basin monomer are dynamic coil design.
　　Earphone speaker accessories speaker sound principle 2: electromagnetic. A movable iron chopper (armature) is set in the middle of a U-shaped magnet. When the current flows through the coil, the armature will be magnetized and the magnet will produce the phenomenon of attraction and repulsion, and drive the diaphragm to move at the same time. This kind of design is cheap but ineffective, so it is often used in the telephone barrel and small earphone.
　　Headphone speaker accessories speaker sound principle 3: inductive. It is similar to the electromagnetic principle, but the armature is doubled, and the two voice coils on the magnet are asymmetric. When the signal current passes through, the two armatures will push each other for different magnetic flux. Unlike electromagnetism, inductance can regenerate at a lower frequency, but its efficiency is very low.
　　Earphone speaker accessories of the speaker sound principle 4: electrostatic. The basic principle is Coulomb's law, which is usually treated by vacuum vaporization of plastic film and aluminum and other inductive materials. The two films are placed face to face. When one of them is applied with positive current and high voltage, the other one will induce a small current. By mutual attraction and repulsion, the air will be pushed to produce sound. Due to its light weight and small vibration dispersion, electrostatic monomer is easy to get clear and transparent mid and high pitch, which has no control over bass power, and its efficiency is not high, and it is easy to collect dust when using DC. At present, manufacturers such as Martin Logan have successfully developed a hybrid loudspeaker with static and dynamic coils, which solves the problem of insufficient bass of static body and is widely used in earphones.
　　Headphone speaker accessories of the speaker sound principle 5: flat type. Manufacturers of earphone horn accessories know that the design was first developed by Sony in Japan, and the voice coil design is still the theme of moving coil. However, the conical basin diaphragm is changed into a honeycomb structure plane diaphragm, because of the cavity effect of few people, the characteristics are better, but the efficiency is also low.
　　Earphone speaker accessories of the speaker sound principle 6: ribbon type. Without the 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 has very light weight, excellent transient response and high frequency response. However, the efficiency and low impedance of ribbon horn have always been a great challenge to the expander, which can be represented by apogee. Another way is to have a voice coil, but the voice coil is printed directly on the plastic sheet, which can solve some of the low impedance problems. Magnepang is a leader in this kind of design.
　　The principle of sound production of earphone horn Part 7: horn type. The diaphragm pushes the air at the bottom of the horn to work, because the sound is not diffused during transmission, so the efficiency is very high. However, because the shape and length of the horn will affect the timbre, it is not easy to replay the low frequency. Now most of them are used in giant pa systems or treble units. Klipsch of the United States is an old horn manufacturer.
　　The sound production principle of headphone speaker part 8: there is also an improved ribbon design developed by Dr. Hale in 1973, which is called Hale speaker. Theoretically, it is excellent, but few users in Taiwan. Piezoelectricity is a design that uses piezoelectric materials such as titanic acid and voltage to make it stretch or shrink. Pioneer used high polymer to improve piezoelectricity design and used it in their treble monomer. Ion horn uses high-voltage discharge to make air become a charged mass. After applying AC voltage, these free charged molecules will make sound due to vibration. At present, it can only be used in monomers above high frequency. Philips has also developed an active feedback horn (MFB), in which an active feedback circuit is installed, which can greatly reduce the distortion. These designs are not mainstream at present.