Acoustic transducer with drop ring attached at the resonant node

Abstract

An acoustic transducer includes a housing, a diaphragm, a support plate, a motor and a drop ring. The motor includes a back plate, a front plate, a magnet and a voice coil. The drop ring connects the diaphragm to the drop ring at the periphery of the drop ring. The drop ring extends parallel to the central axis of the housing. The periphery of the support plate is spaced from the motor and connected to the diaphragm at the resonance node of the diaphragm.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 937,380 filed on November 19, 2019 and U.S. Provisional Patent Application No. 63 / 048,240 filed on July 6, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0003]

[0013] Embodiments described herein relate to acoustic transducers. Background Art

[0004] Figure 1 An example cross section through a bass speaker 100 and stacked components is shown. The bass speaker 100 includes a housing or case 105, a diaphragm 110, a motor 115, and a spider 120. The motor 115 includes a back plate 125, a voice coil 130, and a front plate 135. The spider 120 is connected to the voice coil 130 at a molding 140. The bass speaker 100 includes at least two gap offsets. A first gap offset is defined as a distance D1 between the back plate 125 of the motor 115 and the base of the voice coil 130. A second gap offset is defined as a distance D2 between the spider 120 and a portion of the case 105. A third distance D D Can be used to describe the distance between the diaphragm 110 and the front plate 135 . Figure 1 The diaphragm 110 shown in FIG. 1 is a flat diaphragm. Alternatively, some bass enclosures shape the diaphragm 110 (eg, into a cone) to increase the structural rigidity of the diaphragm 110 .

[0005] The bass enclosure 100 includes one degree of freedom (ie, linear motion in a direction orthogonal to the back plate 125). The low frequency acoustic output of the bass enclosure 100 is controlled by the air volume displacement or excursion (eg, how far the diaphragm 110 travels from a rest position). Summary of the invention

[0006] It is very difficult for electro-acoustic designers to achieve high quality bass reproduction in products with small product sizes. The difficulty increases as product sizes become smaller and the desire for high quality bass reproduction remains. Smaller product sizes can be achieved using smaller speakers. However, the physics associated with bass reproduction (i.e., producing low frequency sound waves) does not favor small speakers or speakers with small diaphragm sizes.

[0007] The low frequency output of a subwoofer is controlled by the air volume displacement or excursion (e.g., how far the speaker's diaphragm travels from its resting position). Therefore, the diaphragm operates as a rigid piston that moves in a linear manner when driven by a motor. The resulting linear motion of the diaphragm should closely represent the electrical input waveform to the motor, even at higher amplitudes, which would be required to achieve sound pressure levels that are balanced with other complementary (e.g., higher frequency) speakers in the speaker system. However, bass reproduction requires larger diaphragm excursions. Using large excursions in a subwoofer means that in addition to including the motor components within the speaker, the motion of the diaphragm and attached components should also be considered to prevent mechanical contact between them (e.g., over-excursion, bottoming out, etc.).

[0008] In some embodiments, the acoustic transducer described herein includes a housing, a diaphragm, a support plate, a motor, and a drop ring. The motor includes a back plate, a front plate, a magnet, and a voice coil. The drop ring connects the diaphragm to the support plate at the free periphery of the support plate. The drop ring extends parallel to the central axis of the housing. The free periphery of the support plate is spaced apart from the motor and connected to the diaphragm at the resonant node of the diaphragm.

[0009] In some embodiments, the method of manufacturing an acoustic transducer described herein includes determining a nodal point of a diaphragm, attaching the diaphragm to a housing or basket via a surround suspension, attaching a support sheet to a drop ring at a free periphery of the support sheet, and attaching the drop ring to the diaphragm at the nodal point.

[0010] Thus, the embodiments described herein enable the depth or thickness of the subwoofer to be reduced by utilizing the space around the motor to reduce the drop ring while ensuring stability or rigidity of the subwoofer during operation. For example, by mounting the drop ring radially away from the motor assembly or mounted radially outside the motor assembly and parallel to the central axis, the drop ring utilizes the same linear space as the motor and the allowance of the motor. The drop ring therefore does not need to provide a separate allowance for its own movement. The allowance of the motor and the allowance of the drop ring are effectively combined into a single allowance without sacrificing the performance of the subwoofer.

[0011] Additionally, a drop ring mounted radially away from the motor assembly can be connected to the diaphragm at a location that helps maintain the stiffness of the diaphragm until the woofer is attenuated out of the system and the higher frequency speaker frequencies are used. This location is determined by a dynamic analysis of the speaker assembly, such as the location of the resonant node of the diaphragm.

[0012] As an additional thermal robustness consideration, since the drop ring is mounted radially away from the motor assembly, voice coil heating does not affect the bearing plate adhesive bond. The combination of high mechanical stress and thermal heat transfer from the voice coil can lead to motor detachment and is a common failure mode in drivers.

[0013] In addition, because the support plate is mounted radially away from the motor assembly, the support plate has an increased overall diameter (outer diameter and inner diameter). The increased diameter of the support plate improves the axial linearity of the support plate movement because deformation of the support plate results in lower mechanical stress. For this reason, the increased diameter of the support plate also improves the performance and reliability (e.g., robustness) of the motor.

[0014] With respect to the processes, systems, methods, heuristics, etc. described herein, it should be understood that although the steps of the processes, etc. have been described as occurring according to a certain ordered sequence, the processes may perform the steps in an order other than the order described herein. It should be further understood that certain steps may be performed simultaneously, other steps may be added, or certain steps described herein may be omitted. In other words, the descriptions of the processes herein are provided for the purpose of illustrating certain embodiments and should not be construed in any way as limiting the claims.

[0015] Therefore, it should be understood that the above description is intended to be illustrative, not restrictive. In addition to the embodiments provided, many embodiments and applications become clear after reading the above description. The scope should not be determined by reference to the above description, but by reference to the appended claims, and the full range of equivalents to which these claims are entitled. Future developments are expected and intended to appear in the technology discussed herein, and the disclosed systems and methods will be incorporated into such future embodiments. In short, it should be understood that the present application is subject to modification and variation.

[0016] All terms used in the claims are to be given their broadest reasonable interpretations and their ordinary meanings as understood by those skilled in the art unless expressly indicated to the contrary herein. In particular, use of singular clauses such as "a", "an", "the", etc., should be understood to recite one or more of the specified elements unless expressly limited to the contrary in a claim.

[0017] Other aspects of embodiments of the invention will become apparent through consideration of the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A subwoofer is shown.

[0019] Figure 2 is a perspective view of a bass enclosure according to embodiments described herein.

[0020] Figure 3 yes Figure 2 Side view of the subwoofer.

[0021] Figure 4 According to the embodiments described herein Figure 2 Perspective view of the subwoofer with the diaphragm removed.

[0022] Figure 5 According to the embodiments described herein Figure 2 A cross-sectional perspective side view of a subwoofer speaker.

[0023] Figure 6 According to the embodiments described herein Figure 2 Cross-sectional side view of a subwoofer enclosure.

[0024] Figure 7 A bass enclosure according to embodiments described herein is shown.

[0025] Figure 8 A bass enclosure according to embodiments described herein is shown.

[0026] Fig. 9A A bass enclosure according to embodiments described herein is shown.

[0027] Fig. 9B A bass enclosure according to embodiments described herein is shown.

[0028] Fig.10 A bass enclosure according to embodiments described herein is shown.

[0029] Fig.11A , 11B and 11C show a drop ring configuration for a bass enclosure.

[0030] Fig.11D yes Fig.11A , 11B and a graph of the relationship between sound pressure and frequency for the falling ring configuration shown in FIG. 11C .

[0031] Fig. 12A , 12B and 12C show a drop ring configuration for a bass enclosure.

[0032] Fig.12D yes Fig. 12A , 12B and 12C for a graph of sound pressure versus frequency for a falling ring configuration.

[0033] Fig.13A , 13B , 13C and 13D show drop ring configurations for a bass enclosure.

[0034] Fig.13E yes Fig.13A , 13B , 13C and 13D are graphs showing the relationship between sound pressure and frequency for the falling ring configuration.

[0035] Fig.13F With and without low pass filter Fig.13D A graph of sound pressure versus frequency for the falling ring configuration shown. DETAILED DESCRIPTION

[0036] Figure 2 and Figure 3 An embodiment of an acoustic transducer 200 (eg, a speaker, a subwoofer, etc.) is shown. Figure 2 and Figure 3 The acoustic transducer 200 shown is a bass enclosure that includes a housing or casing 205 (eg, a generally cylindrical frame), a diaphragm 210, a dust cap 215, and a surround 220. The bass enclosure 200 is configured to reduce or minimize the depth D of the bass enclosure 200. S (See Figure 3 ). In order to reduce or minimize the depth D of the bass enclosure 200 S The internal structure of the bass speaker 200 is designed to maximize the use of the internal space of the bass speaker 200.

[0037] Figure 4 The bass enclosure 200 is shown with the diaphragm 210, dust cap 215 and surround 220 removed. Figure 4 As shown, the bass enclosure 200 includes a support or damping support 400, a molded part 405, a voice coil 410, and an auxiliary component or drop ring 415 (e.g., a connector, a rigid link, or a similar component for fixing the damping support 400 to the diaphragm). The molded part 405 and the drop ring 415 are generally parallel to each other relative to the central axis of the housing 205. In some embodiments, the molded part 405 and / or the drop ring 415 are made of aluminum, foam plastic, or a similar material. In some embodiments, the molded part 405 and / or the drop ring 415 are manufactured as part of the diaphragm 210.

[0038] Subwoofer 200 Figure 5 is shown in a perspective cross-sectional view. Figure 5 As shown, the bass speaker 200 includes a motor 500. The motor 500 includes a back plate 505, a front plate 510, a magnet 515, a molded part 405, and a voice coil 410. Since the support sheet 400 is installed outside the motor 500 or radially away from the motor 500 (for example, relative to the central axis of the housing 205), relative to Figure 1As a comparison of the bass enclosure 100, the support sheet 400 has an increased inside diameter and outside diameter D 支承片 The larger diameter of the support plate 400 improves the axial linearity of the movement of the support plate 400 because deformation of the support plate 400 generates lower mechanical stresses. The increased diameter of the support plate 400 also improves the performance and reliability (eg, robustness) of the motor 500.

[0039] In some embodiments, the diameter D of the support sheet may be greater than or equal to 0.01 mm, depending on, for example, the material used to make the bass enclosure 200. 支承片 Greater than the diameter D of the diaphragm 210 隔膜 In other embodiments, the diameter D of the support sheet may be 200 mm or less, depending on, for example, the material used to make the bass enclosure 200. 支承片 Approximately equal to the diameter D of the diaphragm 210 隔膜 In other embodiments, the support sheet D may be formed of a material such as a material used to manufacture the bass enclosure 200. 支承片 The diameter D of the diaphragm 210 is smaller than the diameter D of the diaphragm 210 隔膜 In some embodiments, the bass enclosure 200 includes more than two drop rings.

[0040] Reference Figure 6 , the bass enclosure 200 includes a central axis 600 relative to a rear surface of the bass enclosure 200. The drop ring 415 is spaced apart from the motor 500 (e.g., the support sheet 400 is not physically connected to the motor 500). In some embodiments, the drop ring 415 is spaced apart from the motor 500 (e.g., the support sheet 400 may be physically connected to the motor 500). The drop ring 415 is connected to the diaphragm 210 at a first end or periphery of the support sheet 400 and is connected to the diaphragm 210 at a node location 605 corresponding to a vibration resonance node of the diaphragm 210. The support sheet 400 is connected to the housing 205 at a second end or periphery. In some embodiments, a distance D is measured from the central axis 600 of the bass enclosure 200 to the node location 605 (e.g., to the drop ring 415 and the support sheet 400) N .

[0041] The node location 605 corresponds to the minimum motion area around which the diaphragm 210 is subjected to bending. The location of the node location 605 on the diaphragm 210 can vary depending on a number of variables, such as the size of the subwoofer 200, the size of the diaphragm 210, the thickness of the diaphragm 210, the material from which the diaphragm 210 is constructed, etc. Each of these variables can affect the bending resonant frequency of the diaphragm 210, and therefore can also affect the location of the node location 605. The node location 605 can be located using, for example, a finite element model having inputs related to the material of the subwoofer 200 and the geometry of the subwoofer 200. By locating the connection between the drop ring 415 and the diaphragm 210 at the node location 605, the stiffness and stability of the diaphragm are improved, while the bending resonance is reduced. Stabilizing the diaphragm 210 in this manner improves the performance of the subwoofer 200 near the upper frequency limit produced by the subwoofer. For example, in some embodiments, the subwoofer 200 is configured to produce frequencies in the range of about 30 Hertz (Hz) to about 200 Hz. With improved performance at the upper end of the frequencies produced (ie, near 200 Hz), the subwoofer is able to produce high quality sound up to the upper end of the subwoofer 200, at which point the subwoofer 200 is attenuated out of the system and a higher frequency speaker is used.

[0042] Positioning the node location 605 of the bass enclosure 200 can be accomplished using physical modeling techniques (e.g., finite element method ["FEM"]). FEM can be used to position the node location and dynamically tune the structure of the bass enclosure 200 so that the bending resonance that is typically present in the diaphragm 210 can be manipulated (e.g., changed in frequency and / or reduced in amplitude). For example, the resonance can be manipulated by modifying the attachment location of the drop ring 415 to the diaphragm 210, modifying the mass of the diaphragm 210, modifying the mechanical damping of the support sheet 400, etc. Such manipulation of the resonance of the diaphragm 210 enables the diaphragm 210 to use a flat (e.g., non-tapered) design. The flat diaphragm 210 allows the overall depth of the bass enclosure 200 to be reduced compared to a non-flat diaphragm. Thus, the bass enclosure 200 does not use a concave or tapered diaphragm to increase the rigidity of the diaphragm, which may result in a depth penalty.

[0043] Figure 7 Another embodiment of an acoustic transducer 700 is shown. Figure 7 The acoustic transducer 700 shown in FIG. 7 is a bass speaker 700. The bass speaker 700 includes a housing or shell 705, a diaphragm 710, a support sheet 715, and a motor 720. The motor 720 includes a back plate 725, a front plate 730, a magnet 735, a voice coil 740, and a molding 745. The bass speaker 700 also includes a drop ring 750 and a central axis 755 of the housing 705. Figure 7 As shown, the molding 745 and the drop ring 750 are respectively substantially parallel to the central axis 755 of the bass enclosure 700 .

[0044] With regard to the above Figure 6 Similar to the construction of , the drop ring 750 is connected to the diaphragm 710 at the node 760. The distance D to the node 760 is N is measured from the central axis 755 of the bass enclosure 700. Figure 7 The bass speaker 700 (or Figure 2-6 In the case of an auxiliary drop ring configuration of the bass speaker 200 shown in FIG. 750 , a gap offset relative to the moving portion of the bass speaker 700 can be defined. The first gap offset is defined as a first distance D1 between the back plate 725 of the motor 720 and the base of the voice coil 740. The second gap offset is defined as a second distance D2 between the support plate 715 and the rear portion of the housing 705. Due to the presence of the drop ring 750, the second distance D2 that defines the second gap offset also defines the gap offset of the diaphragm 710. In addition, a third distance D3 can be used to describe the distance between the diaphragm 710 and the front plate 730. In some embodiments, the first distance D1 is greater than the second distance D2 and the third distance D3. In other embodiments, the first distance D1 is approximately equal to the second distance D2 and the third distance D3. In some embodiments, the third distance D3 is greater than the second distance D2. In other embodiments, the third distance D3 is approximately equal to the second distance D2. In other embodiments, the third distance D3 is less than the second distance D2.

[0045] Figure 8 A partial view of an acoustic transducer 800 of another embodiment is shown. Figure 8The acoustic transducer 800 shown is a subwoofer enclosure 800. The following description of further embodiments focuses on the differences from the previously described embodiments. Therefore, it should be assumed that the features of the previously described embodiments are or at least can be implemented in these further embodiments, unless explicitly stated otherwise. The subwoofer enclosure 800 includes a housing or shell 805, a diaphragm 810, a support sheet 815, an auxiliary member or drop ring 820, a central axis 825 of the housing 805, and an interior 830 of the housing 805. The subwoofer enclosure 800 is similar to the other subwoofer enclosures described herein in that the drop ring is substantially parallel to the central axis 825 of the subwoofer enclosure 800. However, the subwoofer enclosure 800 has a support sheet 815 that is connected to the drop ring 820 at a first end and to an interior portion 830 of the housing 805 at a second end. Connecting the support sheet 815 to the interior 830 of the cage 805 such that the support sheet 815 is positioned inside the drop ring 820 produces a different stiffness-displacement characteristic than when the support sheet is positioned outside the drop ring 820. In some embodiments, such a configuration provides a useful counterbalancing compared to when the support sheet is positioned outside the drop ring 820.

[0046] Fig. 9A A partial view of an acoustic transducer 900 of another embodiment is shown. Fig. 9A The acoustic transducer 900 shown in is a bass speaker 900. The following description of further embodiments focuses on the differences from the previously described embodiments. Therefore, it should be assumed that the features of the previously described embodiments are or at least can be implemented in these further embodiments, unless explicitly stated otherwise. The bass speaker 900 includes a housing or shell 905, a diaphragm 910, a first support sheet 915, a second support sheet 920 (e.g., to provide additional damping), a central axis 925 of the housing 905, and a motor 930. Fig. 9A The subwoofer 900 shown in the figure does not include a drop ring. Instead, the diaphragm 910 is curved inwardly to connect with the first support plate 915 and the second support plate 920. In other embodiments, the subwoofer 900 includes a drop ring to which both the first support plate 915 and the second support plate 920 are connected. Incorporating the first support plate 915 and the second support plate 920 provides design flexibility in achieving the target stiffness-cheapness characteristics of the subwoofer 900 (e.g., to improve the large signal performance of the motor 930).

[0047] Fig. 9B A partial view of acoustic transducer 900 is also shown. Fig. 9BThe acoustic transducer 900 includes a reinforced cover ring 935. The cover ring 935 functions as a support ring for the diaphragm 910 to increase the structural rigidity of the diaphragm 910. In some embodiments, the cover ring 935 is adhered (e.g., glued) to the diaphragm after the diaphragm is manufactured.

[0048] The embodiments described herein also include methods of manufacturing or constructing an acoustic transducer (e.g., a speaker, a subwoofer, etc.). The following description of further embodiments focuses on the differences from the previously described embodiments. Therefore, it should be assumed that the features of the previously described embodiments are or at least can be implemented in these further embodiments, unless explicitly stated otherwise. For example, with reference to Fig.10 In an embodiment of the acoustic transducer 1000, manufacturing the acoustic transducer includes providing a housing or shell 1005. The diaphragm 1010 is attached to the housing 1005. The support sheet 1015 is attached to the housing 1005 at a first periphery of the support sheet 1015. The support sheet 1015 is attached to a member or drop ring 1020 at a second periphery of the support sheet. The second periphery of the support sheet 1015 is spaced from the motor. In some embodiments, the drop ring 1020 is parallel to a central axis 1025 of the housing 1005. As previously described, the method of manufacturing the acoustic transducer 1000 includes determining a node location 1030 of the diaphragm 1010. The drop ring 1020 is then attached to the diaphragm 1010 at the node location 1030. Fig.10 The double-sided arrow in FIG. 1 shows that the node portion 1030 may be located at different positions of the diaphragm 1010 and the distance D to the node portion 1030 may vary according to the variation of the properties or characteristics of the acoustic transducer 1000 between different transducers. N Can vary from transducer to transducer.

[0049] Specifically, Fig.10 1025. The node locations 1030 are shown as being positioned relative to the central axis 1025. For example, the node locations 1030 can be located in a radial direction closer to or farther from the central axis 1025. Using numerical modeling tools (e.g., FEM) to determine where the node locations 1030 are located can take into account the distributed model behavior of the subwoofer 1000 and its structure. Using these numerical modeling techniques, the resonant behavior of the diaphragm 1010 (e.g., harmonic distortion), the stiffness of the diaphragm 1010, and the excursion characteristics of the subwoofer 1000 can all be balanced to achieve a desired performance level.

[0050] Figures 11A-11C A partial view of another embodiment of an acoustic transducer 1100 is shown with some components removed for illustration purposes. Figures 11A-11CThe acoustic transducer 1100 shown is, for example, a bass box 1100. The following description of further embodiments focuses on the differences from the previously described embodiments. Therefore, it should be assumed that the features of the previously described embodiments are or at least can be implemented in these further embodiments, unless explicitly stated otherwise. Fig.11A The acoustic transducer 1100 in the embodiment includes a diaphragm 1105 and a molded part 1110. Fig.11A The acoustic transducer 1100 is shown without a drop ring in order to illustrate the improved performance of the acoustic transducer 1100 when a drop ring is included in the acoustic transducer 1100 . Fig. 11B A drop ring 1115 is shown positioned at a node location of the diaphragm 1105. The drop ring 1115 is, for example, made of a lightweight foam plastic material and has a uniform width (eg, rectangular in shape) of approximately 2 mm. Fig. 11C A drop ring 1115 is shown positioned outside of the node region of the diaphragm 1105 (ie, further away from the center of the diaphragm than the node region).

[0051] Fig.11D It is shown Fig.11A , 11B and 11C are relationship graphs of the frequency response characteristics of the acoustic transducer 1100. When the frequency of the acoustic transducer 1100 reaches approximately 125 Hz (i.e., the resonant frequency of the acoustic transducer 1100), the embodiment of the acoustic transducer 1100 that does not include a drop ring shows a significant reduction in sound pressure. The bending associated with the resonance of the diaphragm assembly causes sound pressure loss and produces undesirable harmonic distortion in the output of the speaker. As such, the higher the frequency at which the diaphragm assembly resonance occurs, the better the performance of the acoustic transducer 1100. If the acoustic transducer 1100 is a subwoofer, it will not typically operate at frequencies greater than approximately 200 Hz, and allowing the sound pressure reduction to occur at frequencies greater than 200 Hz will significantly improve the overall performance of the acoustic transducer 1100. Fig.11D As shown, both embodiments of the acoustic transducer 1100 including the falling ring 1115 (at the node and outside the node of the acoustic transducer 1100) show a reduction in sound pressure at frequencies greater than about 200 Hz (e.g., about 250 Hz). Therefore, the falling ring 1115 significantly improves the frequency response characteristics of the acoustic transducer 1100.

[0052] Figures 12A-12C A partial view of another embodiment of an acoustic transducer 1200 is shown with some components removed for illustration purposes. Figures 12A-12C The acoustic transducer 1200 shown is, for example, a bass box 1200. The following description of further embodiments focuses on the differences from the previously described embodiments. Therefore, it should be assumed that the features of the previously described embodiments are or at least can be implemented in these further embodiments, unless explicitly stated otherwise. Fig. 12A The acoustic transducer 1200 in FIG. 1 includes a diaphragm 1205 and a molded part 1210. Fig. 12A The acoustic transducer 1200 is shown without a drop ring in order to illustrate the improved performance of the acoustic transducer 1200 when a drop ring is included in the acoustic transducer 1200 . Fig. 12B A drop ring 1215 is shown positioned at a node location of the diaphragm 1205 . Fig. 12C A drop ring 1215 is shown positioned outside of the node region of the diaphragm 1205 (ie, further away from the center of the diaphragm than the node region).

[0053] The drop ring 1215 is made of, for example, a lightweight foam plastic material and has a trapezoidal shape. Compared to a drop ring of a standard shape (such as a rectangle), the trapezoidal shape creates a larger adhesion area between the drop ring 1215 and the diaphragm 1205, but adds less mass. Limiting the mass of the drop ring 1215 helps to increase the resonant frequency of the acoustic transducer 1200. The first or smaller end of the trapezoidal drop ring 1215 will be connected to the support plate of the acoustic transducer 1200. The second or larger end of the trapezoidal drop ring 1215 is connected to the diaphragm 1205. Fig. 12B and 12C In the illustrated embodiment, the ratio of the larger end of the trapezoidal drop ring 1215 to the smaller end of the trapezoidal drop ring 1215 is approximately 4:2. In some embodiments, the smaller end of the trapezoidal drop ring 1215 has a width of approximately 2 mm, and the larger end of the trapezoidal drop ring 1215 has a width of approximately 4 mm. Fig. 12B In the illustrated embodiment, the node location of the acoustic transducer 1200 is located at the center of the larger end of the trapezoidal drop ring 1215 .

[0054] Fig.12D It is shown Fig. 12A , 12B and 12C are relationship graphs of the frequency response characteristics of the acoustic transducer 1200. When the frequency of the acoustic transducer 1200 reaches approximately 125 Hz (i.e., the resonant frequency of the acoustic transducer 1200), the embodiment of the acoustic transducer 1200 that does not include a drop ring again shows a significant reduction in sound pressure. The bending associated with the resonance of the diaphragm assembly results in sound pressure loss and produces undesirable harmonic distortion in the output of the speaker. As such, the higher the frequency at which the diaphragm assembly resonance occurs, the better the performance of the acoustic transducer 1200. If the acoustic transducer 1200 is a subwoofer, it will not typically operate at frequencies greater than approximately 200 Hz, and allowing the sound pressure reduction to occur at frequencies greater than 200 Hz will significantly improve the overall performance of the acoustic transducer 1200. Fig.12DAs shown, both embodiments of the acoustic transducer 1200 including the falling ring 1215 (at the node and outside the node of the acoustic transducer 1200) show a reduction in sound pressure at frequencies greater than about 200 Hz (e.g., about 250 Hz outside the node for the falling ring and about 290 Hz at the node for the falling ring). Thus, the falling ring 1215 significantly improves the frequency response characteristics of the acoustic transducer 1200.

[0055] Figures 13A-13D A partial view of another embodiment of an acoustic transducer 1300 is shown with some components removed for illustration purposes. Figures 13A-13D The acoustic transducer 1300 shown is, for example, a bass box 1300. The following description of further embodiments focuses on the differences from the previously described embodiments. Therefore, it should be assumed that the features of the previously described embodiments are or at least can be implemented in these further embodiments, unless explicitly stated otherwise. Fig.13A The acoustic transducer 1300 in FIG. 1 includes a diaphragm 1305 and a molded part 1310. Fig.13A The acoustic transducer 1300 is shown without a drop ring in order to illustrate the improved performance of the acoustic transducer 1300 when a drop ring is included in the acoustic transducer 1300 . Fig. 13B , 13C 13D shows a drop ring 1315 positioned at a node location of the diaphragm 1305 .

[0056] The drop ring 1315 is made of, for example, a foam plastic material and has a trapezoidal shape. Compared to a drop ring of a standard shape (such as a rectangle), the trapezoidal shape creates a larger adhesion area between the drop ring 1315 and the diaphragm 1305, but adds less mass. Limiting the mass of the drop ring 1315 helps to increase the resonant frequency of the acoustic transducer 1300. The first or smaller end of the trapezoidal drop ring 1315 will be connected to the support plate of the acoustic transducer 1300. The larger second end of the trapezoidal drop ring 1315 is connected to the diaphragm 1305. Fig. 13B In the illustrated embodiment, the ratio of the larger end of the trapezoidal drop ring 1315 to the smaller end of the trapezoidal drop ring 1315 is approximately 6:2. In some embodiments, the smaller end of the trapezoidal drop ring 1315 has a width of approximately 2 mm, and the larger end of the trapezoidal drop ring 1315 has a width of approximately 6 mm. Fig. 13C In the illustrated embodiment, the ratio of the larger end of the trapezoidal drop ring 1315 to the smaller end of the trapezoidal drop ring 1315 is approximately 8:2. In some embodiments, the smaller end of the trapezoidal drop ring 1315 has a width of approximately 2 mm, and the larger end of the trapezoidal drop ring 1315 has a width of approximately 8 mm. Fig.13DIn the illustrated embodiment, the ratio of the larger end of the trapezoidal drop ring 1315 to the smaller end of the trapezoidal drop ring 1315 is approximately 10:2. In some embodiments, the smaller end of the trapezoidal drop ring 1315 has a width of approximately 2 mm, and the larger end of the trapezoidal drop ring 1315 has a width of approximately 10 mm. Fig. 13B , 13C In the embodiment shown in FIG. 13 and FIG. 13D , the node of the acoustic transducer 1300 is located at the center of the larger end of the trapezoidal drop ring 1315 .

[0057] Fig.13E It shows Fig.13A , 13B , 13C and 13D are relationship graphs of the frequency response characteristics of the acoustic transducer 1300. When the frequency of the acoustic transducer 1300 reaches about 125 Hz, which is the resonant frequency of the diaphragm assembly, the embodiment of the acoustic transducer 1300 that does not include a drop ring again shows a significant reduction in sound pressure. The bending associated with the resonance of the diaphragm assembly causes sound pressure losses and produces undesirable harmonic distortion in the output of the speaker. As a result, the higher the frequency at which the diaphragm assembly resonance occurs, the better the performance of the acoustic transducer 1300. If the acoustic transducer 1300 is a subwoofer, it will not typically operate at frequencies greater than about 200 Hz, and allowing the sound pressure reduction to occur at frequencies greater than 200 Hz will significantly improve the overall performance of the acoustic transducer 1300. Fig.13E As shown, each embodiment of the acoustic transducer 1300 including the drop ring 1315 exhibits a reduction in sound pressure at frequencies greater than about 200 Hz (e.g., at least 300 Hz for each embodiment and at least 100 Hz for each embodiment). Fig.13D Therefore, the drop ring 1315 significantly improves the frequency response characteristics of the acoustic transducer 1300.

[0058] Fig.13F It is shown Fig.13D Graphs of frequency response characteristics of acoustic transducer 1300 with and without a low pass filter ("LPF"), such as a fourth order Butterworth LPF, which may be generally applicable to acoustic transducers, such as acoustic transducer 1300, when implemented in a system. Fig.13F As shown, the frequency response characteristic of the acoustic transducer 1300 without LPF undergoes an acoustic output step due to bending resonance at a frequency of about 350 Hz. However, this artifact occurs at a sound pressure level of about 70 dB. The frequency response characteristic of the acoustic transducer 1300 with LPF again undergoes an acoustic output step due to bending resonance at a frequency of about 350 Hz. However, this artifact occurs at a sound pressure level of about 40 dB, which is inaudible when, for example, a mid-frequency transducer is crossed over to reproduce frequencies in this range.

[0059] The systems, methods and devices disclosed herein may take any one or more of the following configurations. Therefore, the present invention may be embodied in any form described herein, including but not limited to the following enumerated embodiments (EEE), which describe the structure, features and functions of certain parts of the present invention.

[0060] (EEE1) A bass speaker comprising:

[0061] case;

[0062] Diaphragm;

[0063] a support sheet; and

[0064] a motor, the motor comprising a back plate, a front plate, a magnet and a voice coil,

[0065] A drop ring connects the diaphragm to the support sheet at a periphery of the support sheet, the drop ring extending parallel to a central axis of the housing.

[0066] wherein the periphery of the support sheet is spaced apart from the motor, and

[0067] Wherein the drop ring is connected to the diaphragm at a resonance node of the diaphragm.

[0068] (EEE2) The bass speaker of (EEE1), wherein the periphery of the support sheet is spaced apart from the motor.

[0069] (EEE3) A bass speaker as described in (EEE1) or (EEE2), wherein the diameter of the outer support plate is larger than the diameter of the outer diaphragm.

[0070] (EEE4) The bass speaker according to any one of (EEE1) to (EEE3), further comprising:

[0071] a first gap offset corresponding to a first distance between the backplate and a base of the voice coil; and

[0072] A second gap offset corresponding to a second distance between the support sheet and the rear portion of the housing.

[0073] (EEE5) The bass speaker of (EEE4), wherein the first distance of the first gap offset is greater than the second distance of the second gap offset.

[0074] (EEE6) The bass speaker of (EEE4) or (EEE5), further comprising:

[0075] A third gap offset corresponds to a third distance between the diaphragm and the front plate.

[0076] (EEE7) The bass enclosure of (EEE6), wherein the third distance of the third gap offset is approximately equal to the second distance of the second gap offset.

[0077] (EEE8) The bass enclosure of any one of (EEE1) to (EEE7), wherein:

[0078] The support plate comprises an outer support plate diameter; and

[0079] The diaphragm includes an outer diaphragm diameter.

[0080] (EEE9) The bass speaker of (EEE8), wherein:

[0081] The outer support sheet has a diameter greater than the outer diaphragm diameter.

[0082] (EEE10) The bass enclosure of any one of (EEE1) to (EEE9), wherein the support sheet is configured to be connected to the housing at a second periphery of the support sheet.

[0083] (EEE11) The bass speaker enclosure according to any one of (EEE3) to (EEE10), further comprising:

[0084] A molded member is configured to connect the voice coil to the diaphragm, the molded member extending parallel to the central axis of the housing.

[0085] (EEE12) The bass enclosure of (EEE1), wherein the support sheet is configured to be connected to the motor at a second periphery of the support sheet.

[0086] (EEE13) A bass speaker as described in (EEE12), wherein the diameter of the outer support plate is smaller than the diameter of the outer diaphragm.

[0087] (EEE14) The bass enclosure of any one of (EEE1) to (EEE13), wherein the diaphragm is a flat diaphragm.

[0088] (EEE15) The bass enclosure of any one of (EEE1) to (EEE14), wherein the drop ring is trapezoidal in shape.

[0089] (EEE16) The bass speaker of (EEE15), wherein a ratio of a length of the first end of the drop ring to a length of the second end of the drop ring is at least 4:2.

[0090] (EEE17) A method of manufacturing a bass speaker, comprising:

[0091] Determine the node location of the diaphragm;

[0092] attaching the diaphragm to the housing;

[0093] attaching the support sheet to a drop ring at a periphery of the support sheet;

[0094] The drop ring is attached to the diaphragm at the node location.

[0095] (EEE18) The method according to (EEE17), wherein:

[0096] The drop ring is parallel to the central axis of the housing.

[0097] (EEE19) The method according to (EEE17) or (EEE18), wherein:

[0098] The periphery of the support sheet is spaced apart from the motor.

[0099] (EEE20) The method according to any one of (EEE17) to (EEE19), further comprising:

[0100] The support sheet is attached to the housing at a second periphery of the support sheet.

[0101] Thus, embodiments described herein provide, among other things, a subwoofer having reduced depth and improved performance near the upper end of the frequency range produced by the subwoofer.

[0102] The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in different embodiments for the purpose of simplifying the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the claimed embodiments include more features than are expressly defined in each claim. On the contrary, as the following claims reflect, the inventive subject matter lies in less than all the features of a single disclosed embodiment. Therefore, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate claim subject.

Claims

1. A bass speaker, comprising: case; Diaphragm; Supporting sheet; as well as a motor, the motor comprising a back plate, a front plate, a magnet and a voice coil, a drop ring connecting the diaphragm to the support sheet at the periphery of the support sheet, the drop ring extending parallel to the central axis of the housing, wherein the periphery of the support sheet is spaced apart from the motor, and wherein the drop ring is connected to the diaphragm at a node location corresponding to a vibration resonance node of the diaphragm, wherein the node location corresponds to a minimum motion region around which the diaphragm undergoes bending, and Among others, physical or numerical modeling techniques have been used to locate the nodal sites and manipulate the bending resonance of the diaphragm.

2. The bass speaker of claim 1, wherein: The periphery of the support sheet is spaced apart from the motor.

3. The bass speaker of claim 2, wherein: The outer support plate diameter is larger than the outer diaphragm diameter.

4. The bass speaker box according to claim 1, further comprising: a first gap offset corresponding to a first distance between the backplate and a base of the voice coil; as well as A second gap offset corresponding to a second distance between the support sheet and the rear portion of the housing.

5. The bass speaker box according to claim 4, wherein: The first distance of the first gap offset is greater than the second distance of the second gap offset.

6. The bass speaker box according to claim 5, further comprising: A third gap offset corresponds to a third distance between the diaphragm and the front plate.

7. The bass speaker box according to claim 6, wherein: The third distance of the third gap offset is approximately equal to the second distance of the second gap offset.

8. The bass enclosure of claim 1, wherein: The support plate comprises an outer support plate diameter; and The diaphragm includes an outer diaphragm diameter.

9. The bass speaker enclosure according to claim 1, wherein: The support sheet is configured to be connected to the housing at a second periphery of the support sheet.

10. The bass speaker enclosure according to claim 9, further comprising: A molded member is configured to connect the voice coil to the diaphragm, the molded member extending parallel to the central axis of the housing.

11. The bass speaker enclosure according to claim 1, wherein: The support plate is configured to be connected to the motor at a second periphery of the support plate.

12. The bass speaker enclosure according to claim 11, wherein: The outer support plate diameter is smaller than the outer diaphragm diameter.

13. The bass speaker enclosure of claim 1, wherein: The diaphragm is a flat diaphragm.

14. The bass speaker enclosure of claim 1, wherein: The drop ring is trapezoidal in shape.

15. The bass speaker enclosure of claim 14, wherein: The ratio of the length of the first end of the drop ring to the length of the second end of the drop ring is at least 4:

2.

16. A method of manufacturing an acoustic transducer, comprising: Determine the node location of the diaphragm; attaching the diaphragm to the housing; attaching the support sheet to a drop ring at a periphery of the support sheet; The drop ring is attached to the diaphragm at the node location, wherein: The drop ring is parallel to the central axis of the housing, Wherein, the node portion corresponds to the vibration resonance node of the diaphragm, wherein the node location corresponds to a minimum motion region around which the diaphragm undergoes bending, and The method further comprises using physical or numerical modeling techniques to locate the node location and manipulate the bending resonance of the diaphragm.

17. The method of claim 16, wherein: The acoustic transducer comprises a motor; and The periphery of the support sheet is spaced apart from the motor.

18. The method according to claim 16, further comprising: The support sheet is attached to the housing at a second periphery of the support sheet.

Images