| 摘要 |
PURPOSE:To provide directivity at both high and low frequency range by arranging a tweeter in the middle of a full band speaker and supplying a signal to the full band speaker through a phase shift circuit and to the tweeter through a high pass filter circuit. CONSTITUTION:A signal is inputted to a full band speaker SP3 through a phase shift circuit 3. A signal is inputted to a tweeter SP4 through a high pass filter circuit 4 while its polarity is inverted. As a result, the phase frequency characteristic is matched for nearly all the band by selecting circuit components of the circuits 3, 4 properly. Thus, the smooth characteristic not causing any trough on the sound pressure frequency characteristic on the frequency axis is obtained. As a result, the narrow directivity is obtained based on the frequency decided by the interval between both speakers at a low frequency range and over a wide range up to the reproduction limit frequency at a high frequency range. |
