Why headphones with white magnet better than headphones with black magnet?

Below are some differences between the white magnet and the black magnet.

The material of the white magnet is Neodymium iron boron (NdFeB)

Ndfeb material (rare earth), made of neodymium nickel and cobalt ect.rare materials after plating through high heat sintering. Its performance is far superior to iron oxide magnet. Now the speaker usually use this magnets.At the same volume,magnetic intensity is strengther than normal iron oxide magnetic intensity,almost more than 10 times.

Its characteristic: under the equivalent magnetic flux its small volume, big power, wide frequency range .Currently the HiFi headphones basically use this magnets.Its shortcomings: the rare earth is widely used in high-tech fields( military, electronics, etc.), but in recent years government control the dosage is very strict, and prices soared.

The materail of black magnet is iron oxide magnet.

Iron oxide magnet: made of the magnetic material powder and iron powder is about 1200 ℃ sintering. Its advantages are cheaper price, the high performance price ratio.

Disadvantages: large size, smaller power, narrow frequency range.