PURPOSE: To decrease the sound pressure peak at a high limit frequency and to extend a usage frequency band, by constituting a core member through gathering small sector-shaped pieces having parallel ribs and bonding a flat member at both sides of the core.
CONSTITUTION: In Figure, 1 shows a core and a surface member (not shown) is sticked to the front and rear surfaces with an adhesives. The core 1 consists of assembly of 6 sector-shaped small pieces 2, the small piece 2 is formed as waved cross section and has a plurality of parallel ribs 3. The said 6 sector- shaped small pieces 2 are assembled so that the prolonged line of the rib 3 can be crossed to the center line of the said core 1. The shape of the 1st order resonance node circles of this flat diaphragm is formed as wave shape as shown in broken lines 4 by taking a circle, about 68% of the outer diameter of the diaphragm as a center. A voice coil bobbin is bonded on the node circle and the bobbin is of circular type as conventinal bobbins.
TAKEUCHI HIROSHI
MURATA KOUSAKU
TAKAYAMA SATOSHI
