| 摘要 |
PURPOSE:To improve performance in a low frequency area by providing a microphone for monitor at a position where sounds to be radiated from both loudspeakers are canceled each other. CONSTITUTION:On a partition wall 5, an air vent 5a to communication an intermediate space C with spaces B and D on both sides of the loudspeaker is bored and at the lower positions of both loudspeakers 1 and 2, an air vent 5b is bored to communication the spaces B and D on both sides of the loudspeaker. At a position on a symmetric surface A in the central part of the input hole 5b, a microphone fitting hole 5c is formed. A microphone 3 for monitor is installed at the microphone fitting hole 5c. Thus, at the microphone 3 for monitor, only external noise (c) is inputted and howling can be prevented from being generated by adding a source signal to a 360 deg. integer multiple feedback signal. Then, the silencing performance is improved. |
