JP2014008348A - Golf club - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a golf club suitable for a device triggered by sound having been collected in a microphone.SOLUTION: A golf club comprises a head 31 to which an impact force is applied by hitting a ball, and a resonance member 32 that is fixed to the head 31 and oscillates at a specific frequency by receiving an impact force. Owing to the configuration of the golf club with the resonance member 32 fixed to the head 31, sound at a specific frequency to cause oscillation of the resonance member 32 is emitted from the head 31 to increase a sound pressure of the sound at the specific frequency. Meanwhile, a noise level becomes lower as a frequency band subject to detection becomes narrower in general. Therefore, by using the sound at the specific frequency as a trigger, the noise level can be reduced while the sound emitted from the head 31 at the specific frequency is maintained in a high level, thereby making it possible to suppress erroneous activation of a device triggered by sound having been collected in a microphone due to ambient noise.

Description

  The present invention relates to a golf club, and more particularly to a golf club suitable for a device that uses a sound collected by a microphone as a trigger.

  Since golf shots are greatly related to the swing of a shot, many golfers are interested in improving their own swings. Therefore, various devices for assisting in improving the swing have been proposed. For example, in Patent Document 1, a form imaged by a video camera is stored in an image memory, and when shot sound (impact sound) is detected by a microphone, form images at a plurality of time points including before that moment are displayed. Form checkers that display as still images or frame-by-frame images have been proposed. Also in Patent Document 2, a practice system for detecting a striking sound (impact sound) with a microphone is proposed.

JP-A-11-221309 JP 2004-357777 A

  In such a device that uses the impact sound collected by the microphone as a trigger, the surrounding noise may be erroneously determined as the impact sound and malfunction. Therefore, in the form checker of Patent Document 1, in order to prevent malfunction, only a high frequency component is taken out by a low cut filter so as not to detect a walking sound or a speaking voice. However, even if only the high-frequency component is extracted with the low-cut filter, the noise cannot be sufficiently removed depending on the type of noise, which may cause malfunction.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide a golf club suitable for a device that uses sound collected by a microphone as a trigger.

  In order to achieve at least a part of the above problems, a golf club of the present invention includes a head to which an impact force is applied by a hit ball and a resonance member that is fixed to the head and vibrates at a specific frequency by the impact force. It is characterized by. According to this configuration, since the resonance member is fixed to the head, a sound having a specific frequency at which the resonance member vibrates is emitted from the head, and the sound pressure of the sound having the specific frequency is increased. Also, the noise level generally decreases as the frequency band to be detected becomes narrower. Therefore, if the sound of a specific frequency is used as a trigger, the noise level can be lowered while keeping the level of the sound of the specific frequency emitted from the head high, so that the sound collected by the microphone is used as a trigger. It is possible to prevent the device from malfunctioning due to ambient noise.

  The specific frequency may be higher than the lowest natural vibration frequency of the head. In general, the main frequency component of the impact sound is the lowest-order natural vibration frequency of the head, and the sound of the natural vibration frequency decreases rapidly as the order increases. Therefore, by making the specific frequency higher than the lowest natural vibration frequency, it becomes easier to discriminate the sound of the specific frequency from the sound of the natural vibration frequency of the head.

  The specific frequency may be higher than a human audible range. By making the specific frequency higher than the audible range, it is possible to reduce the influence on the impact sound that the user listens to.

  The resonant member may be configured to be replaceable. According to this configuration, it becomes easier to change the specific frequency for each golf club. Therefore, when a plurality of users are adjacent to each other and practice golf, it is easy to suppress malfunctions caused by sounds generated by the adjacent users performing shots.

  The head may include a horn that selectively radiates sound of the specific frequency in a specific direction. In this case, by arranging the microphone in a specific direction, the sound pressure of the sound of a specific frequency collected by the microphone is increased, so that it is possible to more easily discriminate the sound of the specific frequency from the ambient noise. it can.

Explanatory drawing which shows the golf swing video recording system using this invention. Explanatory drawing which shows the structure and function of a microphone unit. Explanatory drawing which shows the structure of the head in 1st Example. Explanatory drawing which shows the modification of a resonance member. Explanatory drawing which shows the structure of the head in 2nd Example. Explanatory drawing which shows the structure of the head in 3rd Example. Explanatory drawing which shows the modification of a video recording system.

A. First embodiment:
FIG. 1 is an explanatory view showing a golf swing video recording system 1 (hereinafter also simply referred to as “video recording system 1”) using the present invention. FIG. 1A shows the usage state of the video recording system 1. The video recording system 1 includes a video camera 11 (hereinafter simply referred to as camera 11), a microphone unit 12, and a data processing device 13 having a monitor screen 131. The camera 11 and the microphone unit 12 are connected to the data processing device 13.

  The camera 11 is arranged so that the entire image of the swing when the user (golfer) 2 takes a shot fits in the frame of the camera 11. The microphone unit 12 is a microphone having frequency selectivity and strong directivity, and collects sound of a specific frequency generated mainly in the direction of the user 2. The data processing device 13 is configured as a computer having a CPU, a ROM, a RAM, and a secondary storage device (all not shown), and the CPU executes various programs by executing programs stored in the ROM or the RAM. Is realized. As the secondary storage device, a hard disk drive (HDD), a flash memory, or the like can be used.

  The data processing device 13 displays the video input from the camera 11 on the monitor screen 131 in real time. Thereby, the user 2 can see the state of his / her swing. The data processing device 13 also stores the video input from the camera 11 in the secondary storage device as image data in accordance with the sound input from the microphone unit 12. FIG. 1B is a flowchart showing a flow of processing (video recording processing) for storing video in accordance with sound input from the microphone unit 12.

  In step S1, the data processing device 13 stores the video input from the camera 11 as image data in a previously allocated memory area (allocated memory area). The image data stored in the allocated memory area is overwritten as needed from the old image data. As a result, the last 2-3 seconds of video is stored in the allocated memory area.

  In step S2, the data processing device 13 determines whether or not an acoustic trigger is input. Specifically, the data processing device 13 determines whether or not the sound pressure of a sound having a specific frequency (trigger sound) input from the microphone unit 12 exceeds a predetermined threshold value. If the sound pressure exceeds a predetermined threshold, it is determined that an acoustic trigger has been input, and the process proceeds to step S3. On the other hand, if the sound pressure does not exceed the predetermined threshold, it is determined that no acoustic trigger has been input, and the process returns to step S1.

  In step S3, the data processing device 13 stores in the secondary storage device image data of 2 seconds before and after the time point (trigger point) when the sound pressure exceeds a predetermined threshold value. Specifically, the data processing device 13 performs secondary processing on the image data for 2 seconds before the trigger point and the video image data input from the camera 11 for 2 seconds after the trigger point stored in the allocated memory area. Save to storage. The period for storing the image data can be variously changed. For example, it is possible to store image data for a period of 0.5 to 5 seconds before the trigger point and 0.1 to 2 seconds after the trigger point. Moreover, you may enable it for the user 2 to set these periods. When storing image data in the secondary storage device, the previously stored image data may be overwritten, and the image data is stored in the secondary storage device without overwriting the previously stored image data. May be accumulated. In the former case, the area of the secondary storage device used for storing image data can be reduced. In the latter case, videos of a plurality of swings can be confirmed together later.

  As shown in FIG. 1A, when the user 2 hits a ball (not shown) with the golf club 3, the head 31 of the golf club 3 and the ball collide with each other and impact sound (also called hitting sound or hitting sound). Will occur. When the trigger sound included in the impact sound is collected by the microphone unit 12, a swing image of 2 seconds before and after the impact is recorded. The user 2 can check his / her swing by playing the recorded video at the time of the swing, and can use it for practice. In the first embodiment, the head 31 is configured to increase the trigger sound in order to suppress erroneous determination that an acoustic trigger is input due to ambient noise.

  The recorded video is reproduced based on the user's voice instruction recognized by the data processing device 13 executing the voice recognition program. Note that the reproduction of the video may be performed based on an operation by the user 2 such as a button or a touch panel provided on the data processing device 13 (none of which is shown). However, it is preferable to play back the video based on the user's voice instruction because the played video can be viewed even when the user 2 is away. In addition, in order to accept an instruction by the voice of the user 2, it is also possible to install a separate microphone at the mouth of the user 2 and transmit the voice as wireless data from the microphone to the data processing device 13.

  FIG. 2 is an explanatory diagram showing the configuration and function of the microphone unit 12. As shown in FIG. 2A, the microphone unit 12 includes a plurality of microphones 121 (microphone array) arranged at intervals of the wavelength λ of the trigger sound, and a support bar 122 that supports the plurality of microphones 121. ing.

  FIG. 2B shows how the trigger sound is enhanced by the microphone array. As shown in the graph, the phase of the trigger sound is the same at the positions of the microphones 121 arranged at intervals of the wavelength λ of the trigger sound. Therefore, the trigger sound is enhanced by superimposing the sound collected by the individual microphones 121, and the trigger sound included in the impact sound is selectively collected. Thereby, since the trigger sound can be discriminated from ambient noise, it is possible to suppress malfunction of the video recording system 1 due to noise. The trigger sound can be discriminated by, for example, passing the collected sound through a band pass filter (BPF) and passing the sound of a specific frequency. It is also possible to perform spectral analysis by In these cases, it becomes easier to deal with trigger sounds of different frequencies. On the other hand, when the trigger sound is discriminated by the microphone array, the processing of the signal output from the microphone unit 12 can be omitted, so that the video recording process can be performed more easily.

  FIG. 2C shows how the directivity is enhanced by the microphone array. As shown in FIG. 2C, the same phase surface (broken line) of the trigger sound radiated from the sound source is a plurality of spherical surfaces having a radius difference of wavelength λ. Therefore, when the microphone unit 12 is facing the sound source direction, the trigger sound is enhanced. However, when the microphone unit 12 is not facing the sound source direction, the trigger sound is not enhanced. In this way, by configuring the microphone unit 12 with a plurality of microphones 121 arranged at intervals of the wavelength λ of the trigger sound, the trigger sound generated in the direction of the user 2 can be selectively collected. Therefore, when a plurality of users practice golf adjacent to each other like a golf driving range, it is possible to prevent the video recording system 1 from malfunctioning due to a trigger sound generated by a shot of the adjacent user. it can. The arrangement of the individual microphones 121 constituting the microphone array can be variously changed. For example, the directivity can be increased by arranging a plurality of microphones 121 on a plane perpendicular to the sound source direction and appropriately superimposing the outputs of the microphones 121 after delaying them appropriately. As will be described later, when the influence of a trigger sound generated by another user's shot can be reduced, or when there is no other user performing a shot in the vicinity, the directivity of the microphone unit 12 does not necessarily need to be increased. . In this case, a single microphone can be used instead of the microphone array.

  FIG. 3 is an explanatory diagram showing the configuration of the head 31 of the golf club 3 (FIG. 1A). As shown in the perspective view of FIG. 3A, the head 31 includes a face portion 311, a crown portion 312, a sole portion 313, a toe portion 314, a heel portion 315, and a hosel portion 316 into which a shaft is inserted. have. The head 31 has a hollow structure (shell structure) in which these portions 311 to 316 are integrally formed.

  FIG. 3B shows a cross section of the head 31 cut along the AA plane. As shown in FIG. 3B, in the head 31 of the first embodiment, a cantilever hammer-shaped resonance member 32 formed integrally with the head 31 is provided on the inner surface of the face portion 311. The resonance member 32 includes a frame part 321, a hammer part 322 disposed substantially at the center of the frame part 321, and a connection part 323 that connects the frame part 321 and the hammer part 322.

  When the head 31 collides with the ball, the head 31 itself vibrates in a natural vibration mode determined by the overall shape of the head 31 due to the impact force at the time of collision, and the hammer portion 322 of the resonance member 32 has the hammer portion 322 and the connection portion. It vibrates at a frequency (resonance frequency) determined by the shape of H.323. The vibration of the hammer portion 322 is transmitted to the head 31 through the connection portion 323 and the frame portion 321, so that the sound of the natural vibration mode (natural vibration frequency) of the head 31 and the sound of the resonance frequency are generated. Radiated from the head 31.

  The resonance frequency can be an arbitrary frequency, but is preferably higher than the lowest natural vibration frequency of the head 31. In general, the main frequency component of the impact sound is the lowest-order natural vibration frequency of the head 31, and the sound of the natural vibration frequency decreases rapidly as the order increases. Therefore, by making the resonance frequency higher than the lowest natural vibration frequency, it becomes easy to discriminate the sound of the resonance frequency from the sound of the natural vibration frequency of the head 31. Further, the resonance frequency is 10 times or more of the lowest natural vibration frequency of the head 31 so that the influence of the natural vibration of the head 31 is reduced and it becomes easier to radiate the sound of the resonance frequency from the head 31. More preferably. The resonance frequency is preferably higher than the audible range. By making the resonance frequency higher than the audible range, it is possible to generate a trigger sound without affecting the impact sound that the user 2 listens to. Also, at frequencies higher than the audible range, the amount of attenuation when sound propagates through the air increases, so when multiple users are practicing golf adjacent to each other, a trigger generated by the shots of the adjacent users It is possible to suppress malfunction of the video recording system 1 due to sound.

  The resonance frequency of the resonance member 32 may be different for each type of golf club (type of golf club such as driver or iron, golf club number, golf club model, etc.). In this case, by recording the frequency of the sound detected as the trigger sound in conjunction with the video, the user 2 confirms the use history of the golf club and confirms the state of the swing for each type of used golf club. Is possible. It is also possible to save only the frequency of the sound detected as the trigger sound as a history.

  Further, the resonance frequency of the resonance member 32 may be different for each individual in the same type of golf club. Specifically, a plurality of heads 31 having different resonance frequencies are prepared for the same type of golf club so that the resonance frequencies of the golf club heads 31 of different users are as different as possible. In this way, by changing the resonance frequency for each individual, when a plurality of users are adjacent to practice golf, the video recording system 1 is erroneously detected by the trigger sound generated by the adjacent user performing a shot. It can suppress operating.

  When changing the resonance frequency for each type or individual golf club, it is preferable that the resonance frequency of the golf club owned by the user 2 can be registered in the video recording system 1. If the resonance frequency can be registered in the video recording system 1, the video recording system 1 can discriminate the trigger sound emitted from the golf club of the user 2 from the trigger sound emitted from the golf club of another user. it can. For example, the resonance frequency is registered by inputting the golf club model number and serial number (golf club ID) held by the user 2 and the video recording system 1 searches the database for the resonant frequency based on the model number and serial number. Can be performed. Further, when the registration mode activated based on the operation of the user 2 is executed in the video recording system 1, the user 2 performs a shot, and the frequency of the sound within the predetermined frequency band collected at that time May be registered. Further, the user 2 can register the resonance frequency by directly inputting the resonance frequency to the video recording system 1.

  The resonance member provided in the head 31 can have various shapes such as a cantilever hammer shape as well as a cantilever hammer shape shown in FIG. FIG. 4 is an explanatory view showing a modification of such a resonance member. For example, the resonance member 32a may have a tuning fork shape as shown in FIG. In this case, the resonance frequency is determined by the shape of the tuning fork branch. Further, the resonance member 32b may have a columnar shape as shown in FIG. In this case, the resonance frequency is determined by a thickness (effective thickness) obtained by combining the thickness of the face portion 311 and the thickness of the resonance member 32b. Specifically, the resonance frequency is a frequency at which the wavelength of the sound wave in the face portion 311 and the resonance member 32b is twice the effective thickness. Furthermore, as shown in FIG. 4C, a plurality of resonance members 32c can be arranged in the head 31c from the toe portion 314 toward the heel portion 315. In this case, it is possible to grasp the collision position of the ball by changing the resonance frequency of each resonance member 32c.

  In the first embodiment, the resonance member 32 is provided on the inner surface of the face portion 311, but if the resonance member is inside the head 31, the crown portion 312, the sole portion 313, the toe portion 314, or the heel It can be provided on the inner surface of any part such as the part 315. In addition, the resonance member 32 is not limited to any one of these portions 311 to 315, and may be provided so as to interfere with a plurality of portions. Even in this case, since the head 31 has a shell structure, vibration from the resonance member 32 formed integrally with the head 31 is transmitted to the entire head 31, and a trigger sound is emitted from the head 31. The

B. Second embodiment:
FIG. 5 is an explanatory diagram showing the configuration of the head 31d in the second embodiment. Fig.5 (a) is a perspective view of the head 31d, FIG.5 (b) has shown the cross section which cut | disconnected the head 31d by the BB surface. As shown in FIG. 5B, in the second embodiment, the resonance member 34d is provided on the weight 33d attached to the heel portion 315d of the head 31d without providing the resonance member on the head 31d itself. Other points are the same as in the first embodiment.

  The weight 33d shown in FIG. 5B includes a small diameter portion 331d having a small outer diameter and a large diameter portion 332d having an outer diameter larger than that of the small diameter portion 331d. The small diameter portion 331d and the large diameter portion 332d include A hole 333d that opens outward is provided. The weight 33d is fixed to the head 31d by screws (not shown) provided in the small diameter portion 331d. The resonance member 34d is disposed at a position outside the bottom of the hole 333d. Thereby, since the resonance member 34d is positioned in the hole 333d connected to the external space, the trigger sound emitted from the resonance member 34d is radiated to the outside more efficiently, so that the sound of the trigger sound collected by the microphone unit 12 is obtained. Pressure increases. Therefore, the video recording system 1 (FIG. 1A) can more easily discriminate the trigger sound from the ambient noise. Further, by providing the resonance member 34d on the weight 33d, it becomes easier to change the resonance frequency for each golf club. In the example of FIG. 5B, the resonance member 34d has a tuning fork shape. However, as described in the first embodiment, the shape of the resonance member can be variously changed.

  FIG. 5C shows a modification of the weight. In the weight 33e shown in FIG. 5C, the hole 333e provided in the small diameter portion 331e and the large diameter portion 332e is opened inward, and the resonance member 34e is located at the inner side from the bottom of the hole 333e. It is different from the weight 33d shown in FIG. Even in this case, by providing the resonance member 34e on the weight 33e, it becomes easier to change the resonance frequency for each type or individual golf club. Further, since the hole 333e is not opened to the outside, the air current is prevented from being caught in the hole 333e during the swing, and the increase in air resistance and the generation of sound due to the air current can be suppressed.

  In the second embodiment, the resonance members 34d and 34e are provided on the weights 33d and 33e attached to the head 31d. However, in general, it is only necessary that the resonance members can be exchanged. The resonance member may be provided on the detachable member attached to the head, or the resonance member may be directly attached to the head in a detachable state. In the second embodiment, the resonance members 34d and 34e are attached to the sole side position of the heel portion 315d. However, the attachment positions of the resonance member are the crown side of the heel portion, the toe portion 314, the face portion 311 and the like. It is possible to change to an arbitrary position such as an opposing back portion.

C. Third embodiment:
FIG. 6 is an explanatory diagram showing the configuration of the heads 31f and 31g in the third embodiment. The third embodiment differs from the first embodiment in that the outer shapes of the heads 31f and 31g are different. Other points are the same as in the first embodiment. FIG. 6 shows a cross section of the heads 31f and 31g cut along the BB plane (see FIG. 5A). In the head 31f shown in FIG. 6 (a), thick portions 351f and 352f are provided in the toe portion 314f, and a concave portion 353f having a concave outer surface is formed between the two thick portions 351f and 352f. Yes. The head 31g shown in FIG. 6B is different from the head 31f shown in FIG. 6A in that a recess 353g is formed by recessing the toe 314g. Other points are the same as those of the head 31f shown in FIG.

  In these heads 31f and 31g, the recesses 353f and 353g function as acoustic lenses (horns) for sounds whose wavelengths in the heads 31f and 31g are shorter than the lengths of the recesses 353f and 353g. Therefore, sound having a frequency higher than a predetermined frequency determined by the shapes of the recesses 353f and 353g is focused in the direction of the toe portions 314f and 314g (toe direction). Therefore, by making the resonance frequency of the resonance member 32 higher than the predetermined frequency, the trigger sound generated by the resonance member 32 is selectively radiated in the toe direction. At this time, if the microphone unit 12 arranged in the toe direction is arranged, the sound pressure of the trigger sound collected by the microphone unit 12 becomes high, so that the trigger sound can be more easily distinguished from the ambient noise. Further, since the sound having a frequency higher than the audible range has high straightness, when the resonance frequency is set higher than the audible range, the sound radiated from the recesses 353f and 353g reaches the microphone unit without spreading around. Therefore, by making the resonance frequency higher than the audible range, the sound pressure of the trigger sound collected by the microphone unit 12 can be further increased.

  In the example of FIG. 6, the toe portions 314f and 314g are provided with the recesses 353f and 353g. However, the recesses have a desired trigger sound such as a heel portion 315, a crown portion 312 and a back portion facing the face portion 311. It can change suitably according to a radiation direction. When a plurality of users are practicing golf adjacent to each other like a golf driving range, a recess is provided in the back portion so that no other user has a back so that the video recording system 1 of other users does not malfunction. It is preferable to emit a trigger sound in the direction. In this case, it is possible to further suppress the trigger sound from reaching the microphone unit 12 of the video recording system 1 of another user by making the resonance frequency higher than the audible range.

D. Variations:
The present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

D1. Modification 1:
In the video recording system 1 (FIG. 1A) in each of the above embodiments, the camera 11 for photographing the swing form of the user 2, the microphone unit 12 for collecting the trigger sound, the data processing device 13, and the like. However, at least one of the camera 11 and the microphone unit 12 and the data processing device 13 can be integrally configured. Such a video recording system can be realized by, for example, a tablet terminal 14 provided with a camera 142 in the same direction as the monitor screen 141 as shown in FIG. In this case, the trigger sound may be collected by the microphone 143 included in the tablet terminal 14. In addition to the tablet terminal 14, a smartphone, an electronic book terminal, or the like may be used as the video recording system. As described above, when the video recording system is realized by the tablet terminal 14 or a smartphone, the video recording system can be easily carried. When the tablet terminal 14 or the like is placed on the ground, it is preferable to stand the tablet terminal 14 or the like using a stand so that the monitor screen 141 faces the face of the user 2 (FIG. 1A).

  The monitor screen 141 of the tablet terminal 14 is usually a touch panel, and can detect the touch of the finger of the user 2 on the monitor screen 141. Therefore, the tablet-type terminal 14 may acquire an instruction of two points on the monitor screen 141 by a finger and display a straight line connecting the two points on the monitor screen 141. In this way, as shown in FIG. 7, the reference line can be superimposed and displayed on the image at the time of swing, so that the user 2 can more easily analyze the trajectory of the swing. Become. The two-point instruction by the finger is started based on, for example, the instruction by the user 2 and is acquired in a line entry mode different from the normal operation mode. Further, it is also possible to display a line on the monitor screen 141 based on the locus of the finger that is in contact with the monitor screen 141 in place of the two points on the monitor screen 141. Further, when a protective sheet that allows wiping off paint or ink is attached to the surface of the monitor screen 141, a line can be drawn directly on the monitor screen 141. In addition, although the case where the tablet type terminal 14 was used was demonstrated here, also when using the single data processing apparatus 13 like Fig.1 (a), the monitor screen 131 is a touch panel, or When a protective sheet is provided, line display or the like can be performed in the same manner.

D2. Modification 2:
In each of the above embodiments, the present invention is applied to the driver heads 31 to 31g having a shell structure. However, the present invention is applicable to various heads such as irons and putters as long as the heads are integrally formed. Is possible. Even in these cases, a trigger sound of a specific frequency is emitted from the head by using a resonance member that is formed integrally with the head or is fixed to the head by being provided on a weight fixed to the head. be able to. Therefore, it is possible to record a video during swing according to the trigger sound.

  DESCRIPTION OF SYMBOLS 1 ... Video recording system, 2 ... User, 3 ... Golf club, 11 ... Video camera, 12 ... Microphone unit, 13 ... Data processing device, 14 ... Tablet-type terminal, 31-31g ... Head, 32-32c ... Resonant member, 33d, 33e ... weight, 34d, 34e ... resonant member, 121 ... microphone, 122 ... support bar, 131 ... monitor screen, 141 ... monitor screen, 142 ... camera, 143 ... microphone, 311 ... face part, 311 ... face part, 312 ... Crown part, 313 ... Sole part, 314, 314f, 314g ... Toe part, 315, 315d ... Heel part, 316 ... Hosel part, 321 ... Frame part, 322 ... Hammer part, 323 ... Connection part, 331 ... Small diameter part 331d, 331e ... small diameter part, 332d, 332e ... large diameter part, 333d, 333e ... hole, 351f, 352f ... wall thickness , 353f, 353g ... recess

Claims (5)

A golf club,
A head to which impact force is applied by hitting a ball,
A golf club comprising: a resonance member fixed to the head and vibrating at a specific frequency by the impact force. The specific frequency is a frequency higher than the lowest natural vibration frequency of the head.
The golf club according to claim 1. The specific frequency is higher than the human audible range,
The golf club according to claim 2. The resonant member is configured to be replaceable,
The golf club according to claim 1.   5. The golf club according to claim 1, wherein the head includes a horn that selectively radiates sound of the specific frequency in a specific direction. 6.

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