| 摘要 |
PURPOSE:To decrease the resonance frequency, to increase the absorbing performance and to obtain material excellent in sound-shield performance with low cost, by forming the acoustic device member such as speaker box through sintering of ''Sirasu'' sand nitride. CONSTITUTION:A speaker box is formed with sintering, by mixing ''Sirasu'' sand with 30-40% aluminum powder, heating the mixture at about 1,400 deg.C gaseous nitrogen atmosphere, putting it to a graphite mold in a desired speaker box shape and sintering and forming with hot press at about 1,700 deg.C. The ''Sirasu'' sand nitride (SiN.Al2O3) thus obtained can increase the weight of the speaker box from increased specific gravity, allowing to lower the resonance frequency. Further, inner holes specific to sintered product enables sufficient inner loss to increase the vibration absorption of a box. Further, greater antipressure strength avoids the effect of sound pressure in the box accompanied with speaker drive, the sound shield characteristics are improved and the production of howling can be prevented. |
