| 摘要 |
PURPOSE:To attain the high efficiency, a wide band and flat frequency characteristics at a high band respectively for a speaker center cap provided at the center part of a conical diaphragm, by using a mixture of 4-methylpentene polymer and polypropylene for the base material of said center cap. CONSTITUTION:A mixture of 4-methylpentene polymer and polypropylene is used for the base material of a speaker center cap. For the content of the polypropylene, it is desirable from a density and a softening point of view to use polypropylene of below 2-fold volumetric factor to 4-methylpentene polymer. Such a base material ensures the high efficiency, a wide band and flat frequency characteristics at a high band. Furthermore the heat resistance, water resistance and weather resistance can be improved for the speaker center cap. Such a center cap can be produced consecutively at a high speed. |
