This is a round hole magnet with an outer diameter of 70mm, an inner diameter of 32mm, and a thickness of 15mm. The material is sintered ferrite, anisotropic, and the surface is uncoated. It is mainly used for speakers, speakers, and thickness magnetization.
At present, the magnets on the speakers mainly include sintered neodymium magnets and ceramic ferrite magnets. The magnetic properties of ferrites are relatively poor, and a certain volume is required to meet the driving force of the speakers, so they are generally used in larger audio speakers.
Rare earth magnetic materials (such as NdFeB), the magnetizing flux is much larger than that of ferrite, so using NdFeB magnets does not require a large diameter, so NdFeB is mostly used for small volume speakers, such as automobiles Audio.
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.
Speaker magnets of other sizes;
Ring Magnet for Speakers 21x7x5mm