Speaker magnet material

Is the magnet used in the speaker sintered NdFeB or bonded NdFeB?

With the advancement of technology, the range of speaker speakers is getting wider and wider. loudspeaker are used from mobile phone headphones, MP3 headphones to car audio and so on. Generally speaking, the magnets used in speakers/horn are sintered NdFeB or bonded NdFeb magnets​. What about boron?...