Patent Publication Number: US-11388508-B2

Title: Coaxial loudspeaker

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. 119 to U.S. Provisional Application No. 62/890,892, which was filed on Aug. 23, 2019, the entire contents of which are hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The application relates to the technical field of loudspeakers, and in particular to a coaxial loudspeaker. 
     BACKGROUND 
     The existing coaxial loudspeaker refers to two loudspeakers mounted on the same axial center, namely the tweeter and the woofer that respectively play the high frequencies and the mid-low frequencies. The acoustic low-pass filter is often used in the woofer/transducer of the coaxial loudspeaker. 
     However, the existing coaxial loudspeaker is not satisfactory in every aspect, for example, the improvements are made necessarily in low-pass filter performance of the woofer. Additionally, the common coaxial loudspeaker is susceptible to high-frequency diffraction at the edge of the tweeter. 
     SUMMARY OF THE APPLICATION 
     In view of the problem in the relevant art, the application provides a coaxial loudspeaker, which can at least implement the desired low-pass effect without additional electrical components and can improve the response of the tweeter. 
     The technical solution of the present application is implemented as follows. 
     According to an aspect of the present application, a coaxial loudspeaker is including a cone of a woofer, a waveguide of a tweeter, located at a front end towards an outside/large profile end of the cone and a first cavity. The first cavity includes a resonator and a cavity formed in the cone, and the resonator communicated with the cavity at the large profile of the cone. A side opposite to a position where the resonator is communicated with the cavity is constructed as an orifice plate, the orifice plate is adjacent to the resonator and an orifice portion of the orifice plate is communicated with the resonator. 
     According to an embodiment of the present application, the resonator is located at the front end towards the outside/large profile of the cone. 
     According to an embodiment of the present application, the resonator is a Helmholtz resonator, and is arranged coaxially with the cone. 
     According to an embodiment of the present application, the orifice plate is separated from the waveguide of the tweeter. 
     According to an embodiment of the present application, the coaxial loudspeaker includes a first outer wall surrounding the waveguide and arranged at the periphery of an outer side of the large profile, the first outer wall connected to the large profile and the first outer wall connected to a second outer wall via the orifice plate. The second outer wall is located on a peripheral wall surface of the waveguide. The resonator is located between the first outer wall and the second outer wall. An inner wall of the cone is opposite to the second outer wall to form a channel for communicating. 
     According to an embodiment of the present application, an end of the large profile of the cone, and the first outer wall are connected together via a suspension. 
     According to an embodiment of the present application, the suspension comprises a surround that is bent and extended from the large profile of the cone to connect to the first outer wall, and the surround may be protruded towards or away from an inner direction of the resonator. 
     According to an embodiment of the present application, the orifice plate and the second outer wall are integrally formed. 
     According to an embodiment of the present application, the coaxial loudspeaker includes a low-pass filter used for the woofer, the low-pass filter comprising an inductor having a plurality of coil windings. 
     According to an embodiment of the present application, the orifice portion on the orifice plate includes a plurality of holes arranged at intervals around the waveguide. 
     In the application, by providing the ported cavity on the front end of the acoustic propagation path of the woofer, the resonance can be obtained on the upper region of the frequency response of the loudspeaker, and thus the ported cavity may serve as the acoustic low-pass filter with a peak at the resonant frequency. Therefore, the desired low-pass effect is implemented without any additional electrical component. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       In order to illustrate the technical solutions in the embodiments of the present application in the prior art more clearly, the drawings which are required to be used in the description of the embodiments of the present application are briefly described below. It is obvious that the drawings described below are only some embodiments of the present disclosure. It is apparent to those skilled in the art that other drawings may be obtained based on the accompanying drawings without giving inventive effort. 
         FIG. 1  illustrates a sectional view of a coaxial loudspeaker according to an embodiment of the application. 
         FIG. 2  illustrates a partially enlarged schematic diagram in  FIG. 1 . 
         FIG. 3  illustrates a top view of a coaxial loudspeaker according to an embodiment of the application. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The technical solutions of the embodiments of the present application will be clearly and completely described in the following with reference to the accompanying drawings. It is obvious that the embodiments to be described are only a part the embodiments of the present application rather than all of the embodiments of the present application. All other embodiments obtained by those skilled in the art based on the embodiments of the present application are within the protection scope of the present application. 
     As shown in  FIG. 1 , a coaxial loudspeaker  100  is provided according to an embodiment of the application. The coaxial loudspeaker  100  includes a woofer and a waveguide  130  of a tweeter. The woofer is provided with a cone  102 . The waveguide  130  is located at a front end towards an outside/large profile  104  of the cone  102 . The coaxial loudspeaker  100  further includes a first cavity including a resonator  112  formed on an outer side of the waveguide  130  of the tweeter and a cavity  101  formed in the cone  102 . The resonator  112  communicates with the cavity  101  at the large profile of the cone  102 . One side of the first cavity is constructed as an orifice plate  120 , and an orifice portion  122  of the orifice plate  120  communicates with the resonator  112 . The orifice plate  120  is located on an outward side of an acoustic propagation path of the coaxial loudspeaker  100 , and the orifice plate  120  is adjacent to the resonator  112  and opposite to a position where the cavity  101  is formed in the cone  102 . 
     According to the coaxial loudspeaker provided by the application, the woofer radiates the voice in the ported cavity; and by providing the ported cavity on the front end of the acoustic propagation path of the woofer, the resonance can be obtained on the upper region of the frequency response of the loudspeaker and, thus, the ported cavity may serve as the acoustic low-pass filter with a peak at the resonant frequency. Therefore, the desired low-pass effect is implemented without any additional electrical component. Additionally, the ported cavity is provided and such a structure is transparent to the low frequency and obstructive to the high frequency, so no interference is caused for the woofer, and the structure may serve as a surface for obstructing the high frequency generated by the tweeter. Therefore, the response of the tweeter is not susceptible to the baffle step effect, and may implement the smoothness property. In an embodiment, the overall sensitivity of the tweeter may be improved. 
     It should be understood that any appropriate configuration may be made on the structure of the resonator  112  and the structure of the orifice portion  122  on the orifice plate  120  according to the desired resonance frequency and low-pass effect of the ported resonator  112 , which is not defined by the application thereto. 
     In an embodiment, the resonator  112  may be referred to as a Helmholtz resonator. In an embodiment, the resonator  112  and the cone  102  are coaxially arranged. It may be appropriate to design the structures of the resonator  112  and the orifice portion  122  to obtain the Helmholtz resonance on the upper region of the frequency response. 
     Referring also to  FIG. 1 , in an embodiment, the resonator  112  is located at the end towards the outside/large profile  104  of the cone  102 . The orifice plate  120  and the cavity  101  are located on two opposite sides of the resonator  112 . It should be understood that the front end refers to the front end of the acoustic propagation path of the woofer. 
     In an embodiment, the coaxial loudspeaker  100  may further include a screen  124  located on a surface of a side of the orifice plate  120  towards the resonator  112 , and the screen  124  covers the orifice portion  122  of the orifice plate  120 . The screen  124  may be transparent to low frequency and obstructive to high frequency. As a consequence, the frequency response of the woofer is not modified, and the overall frequency response of the woofer is relatively smooth. 
     As shown in  FIG. 2 , the orifice plate  120  is separated from the waveguide  130  of the tweeter, which is illustrated by the dotted line in  FIG. 2 . More specifically, the orifice portion  122  of the orifice plate  120  is separated from the waveguide  130  of the tweeter. In this way, the Helmholtz resonators of the tweeter and the woofer are not coupled, such that neither the resonance nor the diffraction phenomenon is caused, and the frequency response is smoother. 
     According to an embodiment of the application, the coaxial loudspeaker  100  may further include another low-pass filter for the woofer, the low-pass filter including an inductor having a plurality of coil windings. In an embodiment, the inductor is provided with four coil windings. The inductor of the woofer may have a relatively high inductance, and may serve as a smooth low-pass filter. In an embodiment, the maximum effect of the low-pass filter formed by the inductor is 6 dB/octave. In an embodiment, the low-pass filter may serve as a second-order low-pass filter. Therefore, in combination with the ported resonator  112  and the low-pass filter formed by the inductor, the low-pass filter effect having 24 dB/octave may be obtained. 
     In an embodiment, the coaxial loudspeaker  100  further includes a first outer wall  140  and a second outer wall  145 . The first outer wall  140  is disposed at the periphery of the large profile  104  in a manner of surrounding the waveguide  130 . Furthermore, the first outer wall  140  is connected to the large profile  104  of the cone  102 , and the second outer wall  145  is located on a peripheral wall surface of the waveguide  130 . Additionally, the first outer wall  140  is further connected to the second outer wall  145  together via the orifice plate  120 . As shown in  FIG. 1 , an inner wall of the cone  102  is opposite to the second outer wall  145  to form a channel for communicating. The resonator  112  is located between the first outer wall  140  and the second outer wall  145 , and the orifice portion  122  on the orifice plate  120  is an acoustic outlet of the woofer. 
     In addition, the outer wall  140  is provided with an end  142  distal from the orifice plate  120 , and the end  142  of the outer wall  140  may be connected to the large profile  104  of the cone  102  together via a suspension  150 . In such a manner, the resonator  112  may be provided with a portion located out of a region enclosed by the suspension  150 . In an embodiment, the suspension  150  may be constructed as a surround  152  that is bent and extended from the large profile  104  of the cone  102  to an outer side of the cone  102 , so as to connect to the end of the first outer wall  140  and a bent portion of the surround  152  may be raised towards or away from an inner side of the resonator  112 . In an embodiment, the orifice plate  120  and the second outer wall  145  may be an integral part. 
     As shown in  FIG. 1  and  FIG. 3 , in an embodiment, the orifice portion  122  of the orifice plate  120  is constructed as a plurality of spaced holes arranged around the waveguide  130 . It should be understood that the orifice portion  122  of the orifice plate  120  shown in  FIG. 3  is merely illustrative, and any appropriate configuration may be made on the orifice portion  122  of the orifice plate  120  according to the desired low-pass effect of the ported resonator  112 , which is not defined by the application thereto. The number of the plurality of spaced holes  122  of the orifice plate  120  may be any appropriate value. The shape of the holes  122  of the orifice plate  120  may be any appropriate shape. The holes  122  of the orifice plate  120  may be arranged in any appropriate arrangement manner. 
     The foregoing is only preferred embodiments of the present application and is not intended to limit the present application, and any modifications, equivalent substitutions, improvements and the like within the spirit and principles of the present application are intended to be embraced by the protection scope of the present application.