Coaxial earphone core

A coaxial earphone core comprising:

• a first frame;
• a second frame;
• a magnet system, comprising:
• a first yoke fixed to the first frame;
• a first magnet fixed to the first yoke;
• a second magnet surrounding the first magnet to form a first magnetic gap;
• a second yoke fixed on one side of the first magnet away from the first yoke;
• an annular third magnet fixed to the second yoke;
• a first sound unit, comprising:
• a first diaphragm peripherally mounted on the first frame;
• and
• a first coil fixed to the first diaphragm and inserted into the first magnetic gap;
• a second sound unit coaxially surrounded by the first sound unit, comprising:
• a second diaphragm mounted on the second frame;
• and
• a second coil fixed to the second diaphragm;
• wherein
• the second frame is fixed on one side of the third magnet away from the second yoke;
• the second yoke comprises an annular extending wall bending and extending into the third magnet;
• the extending wall is spaced apart from the third magnet to form a second magnetic gap;
• the second coil is inserted into the second magnetic gap;
• the second diaphragm is located on one side of the first diaphragm facing the magnet system along a vibration direction.