| 摘要 |
PURPOSE:To suppress the peak of reproduced sound pressure frequency characteristics by standing waves so as to obtain flat sound pressure characteristics by providing at least one or more each of loudspeaker units for low- and high-pitched sounds in an acoustic pipe, slit-partition plates inside the acoustic pipe and horn, and a sound absorbing material between the partition plates and acoustic pipe. CONSTITUTION:Slit-partition plates 5 are provided at the opened section of an acoustic pipe 4 and at sections which are equal to the 1/3 of the length of the pipe 4 along the inner surface of the pipe 4 from the front face of a diaphragm of this loudspeaker unit and the sound absorbing material 6 is packed in the spaces between the acoustic pipe 4 and partition plates 5. Part of sound waves led to the opening becomes reflected waves and tends to return to the front face of the diaphragm due to an abrupt change in acoustic impedance produced at the opening section. Such reflected waves can be absorbed by the sound absorbing material 6 provided inside the acoustic pipe and occurrence of standing waves inside the acoustic pipe can be prevented. |
