How the speaker works
When different electron energy is transmitted to the coil, the coil generates an energy that interacts with the magnetic field of the magnet; this interaction will cause the paper plate to vibrate; at the same time, because the electron energy changes at any time, the coil of the speaker will move forward or backward, Therefore, the paper plate of the horn will follow the movement, and the movement will change the density of the air, thereby producing sound. The role of the magnet here is to assist the vibration.
Magnets used in speakers are: ferrite, neodymium nickel cobalt, neodymium iron boron.
NdFeB magnets are the core material of high-end speakers, here are sintered NdFeB magnets to be exact. The magnetic properties of sintered NdFeB magnets are much higher than those of bonded NdFeB magnets, so using it will make the speaker sound better. At the same time, NdFeB magnets are also used in high-end headphones. Such headphones have first-class sound quality, good elasticity, good detail performance, good vocal performance, and accurate sound field positioning.
In terms of application, the magnetic performance of ferrite is relatively poor, and it needs a certain volume to meet the driving force of the speaker, so it is generally used in larger audio speakers.
For the requirements of the working environment of the speaker, the appropriate NdFeB can be selected according to the temperature resistance. For example: N(80℃), M(100℃), H(120℃), SH(150℃), UH(180℃), EH(200℃).
For each temperature, there are different magnetic properties, such as N38, N40, N45, the magnetic force of Nd-Ni-Co is in the middle of Nd-Fe-B and ferrite, but these two can work at high temperature of 300 ℃, so there are special requirements for high temperature ,Can consider it. But the price is relatively expensive.
When we say how much magnetism is in the horn, we mean the diameter of the magnet in the horn. For example, 100 magnetism means that the diameter of the magnet is 100mm.
The magnet of the speaker is not the bigger the better: the magnet is divided into high density, low density, strong magnetic, weak magnetic and so on. Not convenient either. For the same magnetic material, the larger the diameter, the saturation of magnetization, the greater the magnetic field strength, the greater the power of the speaker, the higher the sensitivity of the speaker, and the better the transient response.
And if under the same conditions, the amount of magnetization is different, the power, sensitivity and transient performance of the speakers are different. Therefore, it cannot be simply assumed that the larger the diameter of the horn magnet, the better.
Rare earth magnetic materials (such as NdFeB) have a much larger magnetizing flux than ferrite, so using NdFeB magnets does not require a large diameter. Therefore, NdFeB is mostly used in small volume speakers, such as car audio.
