There are known conventional low sound loudspeaker systems such as disclosed in U.S. Pat. No. 4,064,966, U.S. Pat. No. 4,628,528, and Japanese Laid-Open No. 63-120586.
FIGS. 1A and 1B show examples of the structure of above-described prior art loudspeaker systems.
Above-described prior art loudspeaker systems have a disadvantage that unnecessary high sounds in an acoustic pipe leak out of an aperture.
Furthermore, in above-described prior art low sound loudspeaker systems, the loudspeaker unit is disposed facing in the direction indicated by arrow F same as that of the sound radiation direction of the system. Accordingly, as exemplary shown in FIG. 1B, the thickness t of the cabinet is dependent upon the diameter d of the loudspeaker unit so that there is associated with a difficulty in providing a compact low sound loudspeaker system to be mounted on a vehicle.
The present invention has been made in consideration of the above problems.
It is therefore an object of the present invention to provide low sound loudspeaker systems capable of further attenuating unnecessary high sound components.
It is a further object of this invention to provide low sound loudspeaker systems capable of making small the thickness of a cabinet and mounting the loudspeaker system on a vehicle.