A N C I E N T   P E R C U S S I O N   o f   E A S T   A S I A   -   木 鱼   ( W o o d e n   F i s h ) 

C U R R E N T   P R O T O T Y P E S  :   B A M B O O   R E S I N   3 - D   P R I N T  ;  P L A S T E R - E P O X Y   3 - D   P R I N T  ;  P L A   3 - D   P R I N T;  W A X   3 - D   P R I N T   F O R   B R O N Z E   C A S T                                                                                                                                                                             

C U R R E N T   P R O T O T Y P E S  :   B A M B O O   R E S I N   3 - D   P R I N T  ;  P L A S T E R - E P O X Y   3 - D   P R I N T  ;  P L A   3 - D   P R I N T;  W A X   3 - D   P R I N T   F O R   B R O N Z E   C A S T
                                                                                     
                                                                                     

T E C H N I C A L   D R A W I N G  -  S E C T I O N   R E N D E R I N G     Even wall thickness  is typically a requirement of injection molded designs. An even wall thickness decreases the possibility of manufacturing complications and failures. In conflict with this requisite,  uneven wall thickness  is required (in accordance with the Helmholtz principle of resonance) in order to create an optimal resonant object.   The thicker section of the form (as seen in the section drawing above) is a stabilizing mass, whereas the thinner section is designed to vibrate freely when struck.   The user holds the object by the thicker section and strikes the thinner section. By holding the thicker section in the hand, the thinner section is able to vibrate freely and produce a stable and consistent tone.   Although this is an atypical design for the injection molding process on a large production scale, the design does satisfy both the requirements of a resonant acoustic object and an injection moldable object.   Below is an illustration of the Helmholtz principle in relation to a resonator cavity, followed by relevant explanatory equations. 

T E C H N I C A L   D R A W I N G  -  S E C T I O N   R E N D E R I N G  

Even wall thickness is typically a requirement of injection molded designs. An even wall thickness decreases the possibility of manufacturing complications and failures. In conflict with this requisite, uneven wall thickness is required (in accordance with the Helmholtz principle of resonance) in order to create an optimal resonant object. 

The thicker section of the form (as seen in the section drawing above) is a stabilizing mass, whereas the thinner section is designed to vibrate freely when struck. 

The user holds the object by the thicker section and strikes the thinner section. By holding the thicker section in the hand, the thinner section is able to vibrate freely and produce a stable and consistent tone. 

Although this is an atypical design for the injection molding process on a large production scale, the design does satisfy both the requirements of a resonant acoustic object and an injection moldable object. 

Below is an illustration of the Helmholtz principle in relation to a resonator cavity, followed by relevant explanatory equations. 

R e s o n a n t   f r e q u e n c y   f o r m u l a   f o r   a   s p h e r i c a l   c a v i t y : 

          where   D  =  diameter of sphere
                       d   =  diameter of aperture
          ( D and d in meters, and f in Hertz )