Microphone apparatus

#The present invention relates to a microphone apparatus suitable for use in strong winds at a time of driving a two-wheel vehicle on a road, and especially to a microphone apparatus capable of considerably reducing noise such as wind noise without significantly lowering sensitivity of a microphone.

#Structures as shown in FIGS. 1 and 2 are conventionally known in common as microphone apparatuses.

#A microphone apparatus 100 shown in FIG. 1(A) has a microphone unit “M” mounted on a distal end of a handle “H” and a porous windshield “W” made of urethane foam or the like covering the microphone unit “M”. As shown in an acoustic equivalent circuit in FIG. 1(B), the windshield “W” serves an acoustic function to be an acoustic resistance for the microphone unit “M”. Accordingly, by changing the direction of wind with the windshield “W”, the microphone apparatus 100 shown in FIG. 1(A) is capable of reducing the occurrence of noise due to the microphone unit “M” catching wind noise (wind force noise). Since the windshield “W” works as the acoustic resistance on the acoustic equivalent circuit as the above, reducing the noise to a large degree, however, means increasing the acoustic resistance, thereby relatively lowering sensitivity of a microphone. That is, the ratio of speech signal to noise (SN ratio) is unchanged.

#[FIG. 1] Explanatory views showing a conventional microphone apparatus and an acoustic equivalent circuit thereof.

#[FIG. 2] A schematic view of the other conventional microphone apparatus.

#[FIG. 3] A schematic cross-sectional view of a microphone unit.

#With reference to figures, the present invention will be described in detail below. FIG. 7 is a cross-sectional view showing a microphone apparatus 300 according to the first embodiment of the present invention. FIG. 8 is an exploded perspective view of the microphone apparatus 300. In FIGS. 7 and 8, reference number 1 is a microphone unit that converts a sound wave to an electric signal. Reference number 2 is an armoring body that houses the microphone unit 1. The armoring body 2 comprises a bottom plate 21 having a flat plate shape and a microphone wind shield 22 having a domed shape firmly fixed on the bottom plate 21 by a pressure type adhesive. Between the bottom plate 21 and the microphone windshield 22, a signal line 3 with one end connected to the microphone unit 1 is got through.

#The bottom plate 21 is a nonporous plate material that has a function to shut off an incident sound wave to the microphone unit 1. In the present embodiment, a resin plate (polyester film) having flexibility is used as the bottom plate 21.

#At the bottom of the bottom plate 21 is provided a mounting sheet 4 for fixing the whole microphone apparatus 300 on an object such as a helmet. In the present embodiment, a surface fastener is used as the mounting sheet 4. It is possible to use a double-face adhesive tape instead of the surface fastener.