Patent ID: 11889284
Assignee: SOUND SOLUTIONS INTERNATIONAL CO., LTD.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H  B | IPC H

Claim 0:
1. An Electrodynamic acoustic transducer, comprising:
a frame and/or a housing;
a membrane fixed to said frame or said housing;
a magnet system comprising:
a plurality of center magnets having different magnetic orientations;
a plurality of center top plates each of which being arranged adjacent to one of said center magnets;
a common bottom plate arranged adjacent to said center magnets and opposite to the center top plates; and
an outer magnet circuit region surrounding the center magnets and the center top plates,
wherein airgaps are formed between the center top plates and between the center top plates and the outer magnet circuit region;

a coil arrangement comprising a plurality of voice coils, which are attached to the membrane and which are movably arranged relative to the magnet system in an excursion direction, wherein each of the voice coils comprises an electrical conductor in the shape of loops running around a separate coil axis in a loop section, wherein the coil axes are parallel to the excursion direction, and wherein each of the voice coils surrounds a top plate of the magnet system;
wherein the magnet system is designed to generate a magnetic field transverse to the conductors of the voice coils in the loop sections, and
wherein the ratio, A
     g
    
    ·
    
     h
     m
    
   
   
    
     A
     m
    
    ·
    
     w
     g
    
   
  
  =
  
   
    
     l
     g
    
    ·
    
     h
     tp
    
    ·
    
     h
     m
    
   
   
    
     A
     m
    
    ·
    
     w
     g
    
   
  
 

is below 1,
wg denotes the mean width of all airgaps within the magnet system, which is the average value of diameters of virtual circles inscribed in the airgaps between the center top plates and in the airgaps between the center top plates and the outer magnet circuit region, wherein axes of the virtual circles are parallel to the excursion direction,
Ag denotes the sum of all airgap areas within the magnet system, which is the mean height htp of the center top plates measured in a direction parallel to the excursion direction multiplied by the airgap length lg, which is the total length of an airgap center line connecting the centers of said virtual circles,
hm denotes the mean height of the center magnets measured in a direction parallel to the excursion direction, and
Am denotes the total area of the center magnets when viewed in a direction parallel to the excursion direction.