Speaker system

Abstract

The present technology relates to a speaker system that can improve dustproofness and waterproofness. The speaker system comprises: a speaker unit that has a vibration plate and vibrates the vibration plate to output sound; and a vibration member, wherein a space surrounded by the vibration plate and the vibration member is sealed. The present technology can be applied to a vehicle-mounted subwoofer.

Description

Speaker system

[0001] The present technology relates to a speaker system, and particularly relates to a speaker system capable of improving dust resistance and waterproof performance.

[0002] For example, as an on-vehicle subwoofer, in addition to a general box-type subwoofer, one called a fresh air subwoofer (FAS (Fresh Air Subwoofer)) is known (see, for example, Patent Document 1).

[0003] The FAS is configured of a speaker unit, a small cabinet, and a duct that connects the cabinet and a vehicle, and acoustically has the same configuration as a double bass-reflex speaker. That is, a space inside the small cabinet located on the back side of the speaker unit serves as a first air chamber, infinite air outside the vehicle, that is, a space outside the vehicle serves as a second air chamber, and the first air chamber and the second air chamber are connected by the duct.

[0004] European Patent No. 3282714 Specification

[0005] Incidentally, in an on-vehicle FAS, the space inside the cabinet is the first air chamber, and the first air chamber communicates with the space outside the vehicle (outside air) via the duct. Therefore, there is a risk that water and dust may intrude into the first air chamber from outside the vehicle. That is, it cannot be said that the on-vehicle FAS has high waterproof performance and dust resistance.

[0006] The present technology has been made in view of such circumstances, and is intended to make it possible to improve dust resistance and waterproof performance.

[0007] A speaker system according to one aspect of the present technology includes a speaker unit that has a diaphragm and outputs sound by vibrating the diaphragm, and a vibrating member, wherein a space surrounded by the diaphragm and the vibrating member is hermetically sealed.

[0008] In one aspect of this technology, a speaker system is provided with a speaker unit having a diaphragm that vibrates the diaphragm to produce sound, and a vibrating member. Furthermore, the space enclosed by the diaphragm and the vibrating member is sealed.

[0009] This figure shows an example configuration of an in-vehicle FAS. This figure shows an example of the external configuration of an in-vehicle FAS. This figure shows an example of the acoustic configuration of an in-vehicle FAS. This figure shows the acoustic simulation results of an in-vehicle FAS. This figure shows the acoustic simulation results of an in-vehicle FAS. This figure shows an example configuration of a speaker system to which this technology is applied. This figure shows an example of the acoustic configuration of a speaker system. This figure shows the acoustic simulation results of a speaker system. This figure shows the acoustic simulation results of a speaker system. This figure shows an example of the TS / P of a speaker system. This figure shows measured data of the characteristics of a speaker system. This figure shows a comparison of the characteristics of a speaker system and a sealed subwoofer. This figure shows the change in the characteristics of a speaker system with respect to a change in the aperture ratio. This figure shows an example of the configuration of an opening. This figure shows an example of the configuration of an opening. This figure shows an example of the configuration of an opening. This figure shows an example of the installation of a speaker system.

[0010] The following describes embodiments to which this technology is applied, with reference to the drawings.

[0011] <First Embodiment> <About Automotive FAS> First, a general automotive FAS will be described.

[0012] Figure 1 shows a conceptual diagram of an in-vehicle FAS (Functional Automation System).

[0013] The FAS 11 includes a speaker unit 21 that has a voice coil, diaphragm (cone), magnet, etc., and outputs sound through vibration; a cabinet 22 that covers the speaker unit 21; and a duct 23 connected to the cabinet 22. The duct 23 is also connected to a vehicle sheet metal 24 that forms the floor portion of the vehicle.

[0014] In this example, the upper space in the diagram of the vehicle sheet metal 24 represents the space inside the vehicle's interior, while the lower space in the diagram of the vehicle sheet metal 24 represents the space outside the vehicle's interior, i.e., the space outside the vehicle.

[0015] Furthermore, the small space enclosed by the cabinet 22 on the back side of the speaker unit 21, i.e., on the right side in the diagram of the speaker unit 21, functions as the first air chamber (small air chamber), and the space outside the vehicle functions as the second air chamber. In addition, the space inside the cabinet 22, which becomes the first air chamber, and the space outside the vehicle, which becomes the second air chamber, are connected by a duct 23.

[0016] Figure 2 shows an example of the appearance of FAS11.

[0017] In Figure 2, the left side of the figure shows a cross-section of the FAS 11 viewed from the side, i.e., the same direction as in Figure 1, while the right side of the figure shows a view of the FAS 11 from the front. In Figure 2, the same reference numerals are used for parts corresponding to those in Figure 1, and their explanations are omitted as appropriate.

[0018] In this example, the diaphragm (cone) that makes up the speaker unit 21 is exposed to the outside at the front of the FAS 11, and sound is emitted from the diaphragm into the vehicle interior as it vibrates. In addition, a duct 23 provided at the end of the cabinet 22 is attached to the vehicle sheet metal 24 on the floor of the vehicle.

[0019] When the FAS 11 conceptually shown in Figure 1 is interpreted acoustically and illustrated, it becomes as shown in Figure 3. In Figure 3, the same reference numerals are used for parts corresponding to those in Figure 1, and their explanations are omitted as appropriate.

[0020] In Figure 3, as described above, the small space enclosed by the cabinet 22 on the back of the speaker unit 21 is the first air chamber A11 (small air chamber), and the large space outside the vehicle that communicates with the first air chamber A11 is the second air chamber A12. The space outside the vehicle containing outside air is infinitely large, but here the second air chamber A12 is depicted as a space of finite size.

[0021] Thus, since the FAS 11 has an acoustic configuration with two air chambers, namely the first air chamber A11 and the second air chamber A12, it can be said that the acoustic configuration of the FAS 11 is the same as that of a double bass reflex speaker.

[0022] Figures 4 and 5 show the acoustic simulation results of FAS11.

[0023] Figure 4 shows the simulation results of the Sound Pressure Level (SPL), i.e., the output sound pressure frequency response. In Figure 4, the vertical axis represents SPL, and the horizontal axis represents frequency.

[0024] In Figure 4, curve L11 shows the SPL at each frequency for FAS11, where the volume of the first air chamber A11 is 1 L (1 liter), and curve L12 shows the SPL at each frequency for the infinite box speaker. The infinite box speaker is a speaker in which the speaker unit 21 is provided with a cabinet of infinite size, that is, a speaker in which there is no second air chamber and the volume of the first air chamber is infinite.

[0025] Focusing on curve L11, a dip is observed around 400Hz, and the frequency of this dip corresponds to the resonant frequency of duct 23. Furthermore, it can be seen that FAS 11 achieves output sound pressure frequency characteristics equivalent to those of an infinite box speaker in the frequency band below 50Hz. In particular, below 40Hz, FAS 11 can achieve higher sound pressure than the infinite box speaker.

[0026] Figure 5 shows the simulation results for impedance (IMP). In Figure 5, the vertical axis represents impedance, and the horizontal axis represents frequency.

[0027] In Figure 5, curve L21 shows the impedance of the FAS 11 at each frequency, similar to the case in Figure 4, and curve L22 shows the impedance of the infinite box speaker at each frequency, similar to the case in Figure 4.

[0028] Focusing on curve L21, we can see that the frequency at which the impedance of FAS11 peaks is lower than the frequency at which the impedance of the infinite box speaker peaks. In other words, the lowest resonant frequency f0 of FAS11 is lower than the lowest resonant frequency f0 of the infinite box speaker, indicating that the reproducible frequency band is extended to the lower frequency side.

[0029] The operating principle of FAS11 will be explained.

[0030] A key feature of the FAS 11 is that the first air chamber A11 located on the back of the speaker unit 21 is made extremely small, causing the resonant frequency of the duct 23 to be higher than the operating frequency band of the FAS 11. For example, the resonant frequency of the duct 23 is said to be 300Hz to 400Hz.

[0031] In this way, at frequencies lower than the resonant frequency of the duct 23, i.e., in the operating frequency band of the FAS 11, the diaphragm of the speaker unit 21 and the air inside the duct 23 move in phase. In other words, the speaker unit 21 operates so that the air load mass is added to the vibration system mass (Mms).

[0032] As a result, the FAS 11 becomes an acoustic system equivalent to driving a speaker unit 21 with a large vibration system mass (Mms) with an infinitely large-capacity cabinet. Consequently, the lowest resonant frequency f0 of the FAS 11, i.e., the speaker system (acoustic system), becomes lower than the lowest resonant frequency f0 of the speaker unit 21 itself, expanding the reproducible frequency range to lower frequencies.

[0033] By the way, in the FAS 11 having the configuration shown in Figure 1, the first air chamber A11 is connected to the outside air of the vehicle, that is, the space outside the vehicle, via the duct 23. Therefore, there is a risk that water and dust may enter the first air chamber A11 from outside the vehicle via the duct 23. In other words, the waterproof and dustproof performance of the FAS 11 cannot be said to be high.

[0034] Furthermore, when the FAS 11 is installed in the vehicle, the interior of the vehicle is separated from the outside space (outside air) by only one diaphragm that makes up the speaker unit 21, so there is a concern that noise from outside the vehicle may enter the interior of the vehicle. In addition, because the FAS 11 requires the formation of a small-volume first air chamber A11 and a duct 23, the shape of the FAS 11 itself and the mounting part of the FAS 11 may become complex.

[0035] <Example of speaker system configuration> Therefore, in this technology, the waterproof and dustproof performance can be improved by replacing the duct portion of the FAS described above with a passive radiator from an acoustic perspective.

[0036] Furthermore, this technology can suppress the intrusion of noise from the outside into the vehicle interior, and it also allows for a relatively simple structure for the speaker system that functions as an in-car subwoofer (in-car audio output device).

[0037] For example, in this technology, a passive radiator with the same area and shape as the diaphragm of the driving speaker, i.e., the speaker unit, is used. In such a case, it is only necessary to place the diaphragm and the passive radiator apart and form a shape that seals the first air chamber, which is the space between the diaphragm and the passive radiator, thus making the structure of the speaker system relatively simple.

[0038] This technology has the following features in particular:

[0039] (Feature 1) The lowest resonant frequency f0 of the entire speaker system can be made lower than the lowest resonant frequency f0 of the speaker unit itself. (Feature 2) By making the passive radiator waterproof, dust and water from outside the vehicle can be prevented from entering. (Feature 3) When viewed from inside the vehicle, the separation from the space outside the vehicle (outside air) consists of a total of two components: one diaphragm and one passive radiator, thus reducing the intrusion of noise from outside the vehicle into the vehicle interior.

[0040] For example, regarding feature 1, the FAS 11 shown in FIG. 1 can obtain a lower minimum resonance frequency f0, but the speaker system of the present technology can also achieve expansion of the reproduction band toward the low frequency range.

[0041] Furthermore, for example regarding feature 3, in the above-mentioned FAS 11, when viewed from the vehicle interior, only one diaphragm constituting the speaker unit 21 provides separation from the space outside the vehicle (outside air). In contrast, in the speaker system of the present technology, separation from the space outside the vehicle (outside air) is provided by a total of two vibrating members (diaphragms): one diaphragm and one passive radiator. Therefore, compared with FAS 11, the present technology can further reduce the intrusion of noise from the outside.

[0042] In the following description, an in-vehicle speaker system will be taken as an example of a speaker system to which the present technology is applied. However, the present technology is not limited thereto, and is applicable to mobile object speaker systems mounted on various mobile objects such as trains.

[0043] FIG. 6 is a diagram (cross-sectional view) showing a configuration example of an embodiment of a speaker system to which the present technology is applied.

[0044] The speaker system 61 shown in FIG. 6 is an in-vehicle speaker system that functions as an in-vehicle subwoofer (low-frequency speaker).

[0045] The speaker system 61 includes a speaker unit 71, a frame 72, and a passive radiator 73.

[0046] Furthermore, the speaker system 61 is disposed in the vehicle interior of a vehicle (automobile) and attached to a vehicle sheet metal 74 that forms the space of the vehicle interior. The vehicle sheet metal 74 is a partitioning member that separates the space inside the vehicle (vehicle interior) from the space outside the vehicle. The vehicle sheet metal 74 is provided with an opening 75 that connects the vehicle interior space and the space outside the vehicle. In this example, the opening 75 is constituted by a plurality of holes (openings) formed in the vehicle sheet metal 74.

[0047] In FIG. 6, in the illustration of the vehicle sheet metal 74, the upper space is the space inside the vehicle (vehicle compartment), and the lower space in the illustration of the vehicle sheet metal 74 is the space outside the vehicle.

[0048] Therefore, in this example, in the speaker system 61, the speaker unit 71 is located in the vehicle compartment (the space inside the vehicle), and the passive radiator 73 is arranged adjacent to the opening 75 that connects the space inside the vehicle compartment and the space outside the vehicle in the vehicle compartment.

[0049] The speaker unit 71 is a driving speaker that outputs sound through vibration.

[0050] The speaker unit 71 includes a yoke 81, a magnet 82, a plate 83, a speaker frame 84, a voice coil bobbin 85, a voice coil 86, a damper 87, a diaphragm 88, and a surround 89.

[0051] An annular magnet 82 is fixed to the yoke 81, and a plate 83 made of metal such as iron is further arranged adjacent to the magnet 82. Further, the plate 83 is fixed to the speaker frame 84. In this example, by fixing the speaker frame 84 to the frame 72, the speaker unit 71 is in a fixed state relative to the vehicle sheet metal 74.

[0052] A voice coil 86 is wound around the outer circumference of the voice coil bobbin 85, and the voice coil 86 is arranged such that the voice coil 86 and the plate 83 face each other. The voice coil bobbin 85 is fixed to the speaker frame 84 by the damper 87. In particular, the voice coil bobbin 85 is fixed in a state capable of vibrating in the vertical direction in the drawing.

[0053] Further, a diaphragm 88, also called a cone, is fixed to the voice coil bobbin 85, and the diaphragm 88 is also connected to the speaker frame 84 via the surround 89 serving as a support member. That is, the diaphragm 88 is fixed to the speaker frame 84 in a vibratable state by the surround 89 connected to the outer circumference of the diaphragm 88. The diaphragm 88 is formed of, for example, paper (pulp), foamed mica, metal such as aluminum, fiber such as carbon, polypropylene, or the like.

[0054] For example, when the speaker unit 71 is driven, a current that serves as a drive signal is supplied to the voice coil 86 via a terminal. Due to the Lorentz force, the voice coil bobbin 85 and the diaphragm 88 attached to the voice coil bobbin 85 vibrate vertically in the diagram. In this way, the speaker unit 71 outputs sound corresponding to the drive signal by vibrating the diaphragm 88 based on the drive signal supplied from the outside.

[0055] The frame 72 is attached to the vehicle sheet metal 74 so as to surround the entire opening 75. The passive radiator 73 is positioned between the diaphragm 88 and the opening 75 and is fixed to the frame 72 in a vibrating manner. For example, in this example, the passive radiator 73 is positioned opposite the diaphragm 88 and also opposite the opening 75.

[0056] The passive radiator 73 has a vibrating member 101 and an edge 102. The passive radiator 73, i.e., the vibrating member 101 and the edge 102, also has a waterproof function.

[0057] Similar to the case of the diaphragm 88, the vibrating member 101 is fixed to the frame 72 in a state where it can vibrate by an edge 102, which is a support member connected to the outer circumference of the vibrating member 101.

[0058] For example, the vibrating member 101 may be a diaphragm made of paper (pulp), foamed mica, metal such as aluminum, fiber such as carbon, polypropylene, etc. The vibrating member 101 may be made of the same material as the diaphragm 88, or it may be made of a different material than the diaphragm 88.

[0059] In this example, the shape of the vibrating member 101 is the same as or approximately the same as the shape of the diaphragm 88, and the area (surface area) of the vibrating member 101 is the same as or approximately the same as the area of ​​the diaphragm 88. However, the shape and area of ​​the vibrating member 101 do not necessarily have to be the same as the shape and area of ​​the diaphragm 88; any shape and area are acceptable.

[0060] Furthermore, the passive radiator 73 (vibrating member 101) is positioned opposite the diaphragm 88. More specifically, in this example, the passive radiator 73 is positioned parallel or approximately parallel to the diaphragm 88. Similarly, the passive radiator 73 (vibrating member 101) is positioned opposite the opening 75 in the vehicle sheet metal 74.

[0061] The passive radiator 73 (vibrating member 101) may be positioned at an angle to the diaphragm 88 and the opening 75.

[0062] In the speaker system 61, the space enclosed by the diaphragm 88, edge 89, frame 72, and passive radiator 73 is a sealed, hollow, closed space, and this closed space functions as the first air chamber, which will be described later. In addition, the space on the opposite side of the diaphragm 88 from the passive radiator 73 (vibrating member 101), that is, the space on the side of the opening 75, functions as the second air chamber, which will be described later.

[0063] In the speaker system 61 with the above configuration, when viewed from inside the vehicle, the separation from the space outside the vehicle (outside air) consists of a total of two components: one diaphragm 88 and one passive radiator 73.

[0064] Therefore, the speaker system 61 can further reduce the intrusion of dust, water, and noise from outside the vehicle compared to the case of the FAS 11 described with reference to Figure 1. In other words, the speaker system 61 can improve dustproof performance, waterproof performance, and the effect of suppressing the intrusion of noise into the vehicle interior. Moreover, since the passive radiator 73 provided adjacent to the opening 75 in the speaker system 61 has a waterproof function, dustproof performance and waterproof performance can be further improved.

[0065] Furthermore, in the speaker system 61, the speaker unit 71 and the passive radiator 73 are placed side by side, and the space between the diaphragm 88 and the passive radiator 73 is sealed. Therefore, the structure of the speaker system 61 can be made relatively simpler compared to the FAS.

[0066] When the speaker system 61 shown in Figure 6 is interpreted acoustically and illustrated, it becomes as shown in Figure 7. In Figure 7, the same reference numerals are used for parts corresponding to those in Figure 6, and their explanations are omitted as appropriate. Also, in Figure 7, reference numerals have been omitted for some parts that make up the speaker system 61 in order to make the figure easier to read.

[0067] In Figure 7, the small space enclosed by the speaker unit 71 and the passive radiator 73 is the first air chamber 131 (small air chamber) (functions as the first air chamber 131). Additionally, the larger space adjacent to the first air chamber 131 on the passive radiator 73 side is the second air chamber 132 (functions as the second air chamber 132).

[0068] In reality, the yoke 81 and voice coil 86 of the speaker unit 71 are positioned on the opposite side from the passive radiator 73 when viewed from the diaphragm 88, and the sealed space surrounded by the diaphragm 88 and the passive radiator 73 (vibrating member 101) becomes the first air chamber 131.

[0069] Furthermore, the second air chamber 132 is an infinitely large space adjacent to the first air chamber 131, located on the side of the opening 75 when viewed from the passive radiator 73 (vibrating member 101). In this example, the second air chamber 132 includes not only the space outside the vehicle (the space with air outside the vehicle) but also the space inside the vehicle on the side of the opening 75 when viewed from the passive radiator 73 (vibrating member 101). Note that the space outside the vehicle with outside air is an infinitely large space, but here the second air chamber 132 is depicted as a space of finite size.

[0070] The speaker system 61 has an acoustic configuration that includes two air chambers, namely a first air chamber 131 and a second air chamber 132. In particular, the volume of the first air chamber 131 is smaller than the volume of the second air chamber 132.

[0071] From an acoustic perspective, comparing the configuration of speaker system 61 with the configuration of FAS 11 shown in Figure 1, the configuration of speaker system 61 is the same as that of FAS 11, but with the duct 23 replaced by a passive radiator 73.

[0072] The operating principle of the speaker system 61 will now be explained.

[0073] In the speaker system 61, the first air chamber 131, which is formed by being surrounded by the diaphragm 88 and the passive radiator 73 (vibrating member 101), is made into a small-volume space so that the resonant frequency of the passive radiator 73 is higher than the operating frequency band of the speaker system 61.

[0074] In this way, at frequencies lower than the resonant frequency of the passive radiator 73, i.e., in the operating frequency band of the speaker system 61, the diaphragm 88 of the speaker unit 71 and the passive radiator 73 (vibrating member 101) will move (vibrate) in the same phase.

[0075] Specifically, for example, when the vibration frequencies of the diaphragm 88 and the vibrating member 101 are lower than the resonant frequency of the passive radiator 73, the diaphragm 88 and the vibrating member 101 will move (vibrate) in the same direction as shown in Figure 6.

[0076] This operation can be described as the speaker unit 71 operating in such a way that the vibration system mass of the passive radiator 73 (vibrating member 101) is added to the vibration system mass (Mms) of the speaker unit 71.

[0077] Therefore, the speaker system 61 becomes an acoustic system equivalent to driving a speaker unit 71 with a large vibration system mass (Mms) with an infinitely large-capacity cabinet. Consequently, the lowest resonant frequency f0 of the speaker system 61 becomes lower than the lowest resonant frequency f0 of the speaker unit 71 itself, expanding the reproducible frequency range to lower frequencies.

[0078] Figures 8 to 10 show the acoustic simulation results of the speaker system 61. Here, the diameter of the part consisting of the diaphragm 88 and edge 89, i.e., the diameter of the speaker unit 71, is assumed to be 200 mm, and the effective area of ​​the part consisting of the diaphragm 88 and edge 89 is assumed to be equal to that of the passive radiator 73. The volume of the first air chamber 131 is assumed to be 1.5 L (1.5 liters), and the volume of the second air chamber 132 is assumed to be infinite.

[0079] Figure 8 shows the simulation results of the output sound pressure frequency response (SPL). In Figure 8, the vertical axis represents SPL, and the horizontal axis represents frequency.

[0080] In Figure 8, curve L41 shows the SPL of the speaker system 61 at each frequency, and curve L42 shows the SPL of the infinite box speaker at each frequency.

[0081] An infinite box speaker is a speaker in which the speaker unit 71 is provided with a cabinet of infinite size, that is, a speaker in which there is no second air chamber and the volume of the first air chamber is infinite. In the cases shown in Figures 9 and 10 described below, the infinite box speaker is the same infinite box speaker as in the case of Figure 8.

[0082] In the example shown in Figure 8, a dip occurs around 350 Hz in curve L41, and the frequency of this dip is the resonant frequency of the passive radiator 73. Furthermore, from curves L41 and L42, it can be seen that the speaker system 61 achieves output sound pressure frequency characteristics that are almost equivalent to those of an infinite box speaker in the frequency band below 80 Hz, and especially below 40 Hz.

[0083] Figure 9 shows the simulation results of the amplitude characteristics. In Figure 9, the vertical axis represents amplitude, and the horizontal axis represents frequency.

[0084] In Figure 9, curve L51 shows the amplitude of the diaphragm 88 of the speaker system 61 at each frequency, and curve L52 shows the amplitude of the passive radiator 73 of the speaker system 61 at each frequency. Curve L53 also shows the amplitude of the diaphragm of the infinite box speaker at each frequency.

[0085] Comparing these curves L51 to L53, it can be seen that at each frequency, the amplitudes of the diaphragm 88 of the speaker system 61, the passive radiator 73, and the diaphragm of the infinite box speaker are approximately the same.

[0086] Figure 10 shows the simulation results for impedance (IMP). In Figure 10, the vertical axis represents impedance, and the horizontal axis represents frequency.

[0087] In Figure 10, curve L61 shows the impedance of the speaker system 61 at each frequency, and curve L62 shows the impedance of the infinite box speaker at each frequency.

[0088] Focusing on curve L61, we can see that the frequency at which the impedance of speaker system 61 peaks is lower than the frequency at which the impedance of the infinite box speaker peaks. In other words, the lowest resonant frequency f0 of speaker system 61 is lower than the lowest resonant frequency f0 of the infinite box speaker, indicating that the reproducible frequency range of speaker system 61 is extended to the lower frequency side.

[0089] From the simulation results shown in Figures 8 to 10 above, it can be seen that the speaker system 61 has sufficient characteristics as a subwoofer (low-frequency speaker).

[0090] In the simulations shown in Figures 8 to 10, the parameters shown in Figure 11 are used as the TS / P (Thiele Small Parameter) of the speaker unit 71. Note that these TS / P values ​​are merely examples, and the TS / P values ​​are not limited to those shown in Figure 11.

[0091] In the example shown in Figure 11, the effective vibration area of ​​the speaker unit 71 is 213.82 cm². 2 It is stated that the electrical resistance "Re" of the voice coil 86 is 0.97Ω, the inductance "Le" of the voice coil 86 is 0.381mH, and the lowest resonant frequency "Fs" is 41.6Hz.

[0092] Furthermore, the vibration system mass "Mms" is assumed to be 40.1g, the force coefficient "Bl" is assumed to be 4.185, the equivalent flexible air volume "Vas" is assumed to be 23.548l, the mechanical resonance sharpness "Qms" is assumed to be 12.3, the electrical resonance sharpness "Qes" is assumed to be 0.58, and the overall resonance sharpness "Qts" is assumed to be 0.554. In addition, the calculated output sound pressure "Lnom" is assumed to be 86.86dB.

[0093] Figure 12 shows the actual measured data obtained when the speaker system 61 was prototyped under the same conditions as the TS / P-based simulation shown in Figure 11.

[0094] In Figure 12, the vertical axis represents sound pressure or impedance, and the horizontal axis represents frequency. In other words, in Figure 12, the graph of impedance at each frequency is superimposed on the graph of output sound pressure frequency characteristics.

[0095] Curve L81 shows the sound pressure at each frequency measured in the front direction of the speaker system 61, and curve L82 shows the THD (Total Harmonic Distortion).

[0096] For example, curve L81 shows that the sound pressure decreases around 300 Hz, which is the resonant frequency of the passive radiator 73. Furthermore, it can be seen that a relatively flat output sound pressure frequency response is obtained at frequencies below the resonant frequency of the passive radiator 73.

[0097] Curve L83 shows the impedance when the volume of the second air chamber 132 is 100 L (100 liters), and curve L84 shows the impedance when the second air chamber 132 is a sufficiently large anechoic chamber.

[0098] Comparing these measured results (measured data) with the simulation results shown in Figures 8 and 10, it can be seen that the actual speaker system 61 exhibits characteristics that are approximately equivalent to those of the simulation results.

[0099] The speaker system 61 described above, in principle, has output sound pressure frequency characteristics similar to those of existing FAS. In addition to FAS, existing subwoofers include sealed subwoofers, or box-type subwoofers.

[0100] Figure 13 shows the characteristics of speaker system 61 and a typical sealed subwoofer.

[0101] In Figure 13, the vertical axis represents sound pressure or impedance, and the horizontal axis represents frequency. That is, in Figure 13, as in Figure 12, the graphs of impedance at each frequency are superimposed on the graph of the output sound pressure frequency characteristics.

[0102] In the example shown in Figure 13, the speaker system 61 has a speaker unit 71 with a diameter of 20 cm, that is, the diameter of the part consisting of the diaphragm 88 and edge 89, and the volume of the first air chamber 131 is 1 L (1 liter). The sealed subwoofer has a diaphragm diameter including the edge of 20 cm, and the volume of the air chamber is 10 L (10 liters).

[0103] Curve L91 shows the sound pressure (output sound pressure frequency characteristics) of the speaker system 61 at each frequency, and curve L92 shows the sound pressure of the sealed subwoofer at each frequency.

[0104] Generally, subwoofers are used for frequencies between 50Hz and 80Hz. Therefore, for example, the operating frequency range of a subwoofer is approximately 20Hz to 80Hz, as shown in frame R11 in Figure 13.

[0105] Comparing the sound pressure in this frequency band using curves L91 and L92, it can be seen that the sound pressure of speaker system 61 is higher than that of the sealed subwoofer at most frequencies. In other words, speaker system 61 achieves a good output sound pressure frequency response.

[0106] Furthermore, curve L93 represents the impedance of the speaker system 61, and curve L94 represents the impedance of the sealed subwoofer.

[0107] Comparing these curves L93 and L94, the speaker system 61 has a lower impedance peak frequency than the sealed subwoofer. In other words, the speaker system 61 has a lower lowest resonant frequency f0 than the sealed subwoofer, and its reproducible frequency range is extended to the lower frequencies.

[0108] Thus, with the speaker system 61, compared to a sealed subwoofer, it is possible to enjoy deeper bass (lower frequency sounds) at higher sound pressure levels within the typical frequency range used by subwoofers.

[0109] <Modification> However, when installing the speaker system 61 in a vehicle, it is conceivable that, due to vehicle design and other circumstances, the opening area of ​​the opening 75 facing the passive radiator 73 may not be the same as the area of ​​the passive radiator 73.

[0110] Here, in Figure 6, when viewed from top to bottom, the ratio of the opening area of ​​the opening 75 portion to the area of ​​the passive radiator 73 (vibrating member 101) on the plane is called the opening ratio. For example, the opening ratio is considered to be 100% when the opening area of ​​the opening 75 is equal to the area of ​​the passive radiator 73.

[0111] Figure 14 shows the output sound pressure frequency characteristics and impedance of the speaker system 61 when the aperture ratio is changed.

[0112] In Figure 14, the vertical axis represents sound pressure or impedance, and the horizontal axis represents frequency. Specifically, in Figure 14, graphs of impedance at each frequency for each aperture ratio are superimposed on graphs of the output sound pressure frequency characteristics for each aperture ratio.

[0113] Figure 14 shows the output sound pressure frequency characteristics and impedance for cases where the aperture ratio is 100%, 60%, 40%, and 30%. For example, curve L101 shows the output sound pressure frequency characteristics when the aperture ratio is 30%. Also, for example, curve L102 shows the impedance when the aperture ratio is 30%.

[0114] Focusing on the output sound pressure frequency characteristics at frequencies below 80Hz for each aperture ratio, we see that the sound pressure decreases as the aperture ratio decreases. However, the difference in sound pressure at each frequency is not very large, so it can be seen that there are no practical problems as long as an aperture ratio of 30% or more can be secured.

[0115] Furthermore, focusing on the impedance peaks at each aperture ratio, we can see that the peak frequencies are approximately the same for each aperture ratio. In other words, there is almost no effect on the lowest resonant frequency f0.

[0116] Based on the above, the configuration of the opening 75 can be any configuration as long as it ensures a sufficient opening ratio for the opening 75 relative to the passive radiator 73 (vibrating member 101). A sufficient opening ratio, in this context, is, for example, an opening ratio of 30% or more.

[0117] For example, the configuration of the opening can be as shown in Figures 15 to 17.

[0118] In Figures 15 to 17, the same reference numerals are used for parts corresponding to those in Figure 6, and their explanations are omitted as appropriate. Also, in Figures 15 to 17, reference numerals have been omitted for some parts that make up the speaker system 61 in order to make the figures easier to read.

[0119] Furthermore, in Figures 15 to 17, the upper part of the vehicle sheet metal 74 represents the space inside the vehicle, and the lower part of the vehicle sheet metal 74 represents the space outside the vehicle.

[0120] The example shown in Figure 15 is one in which an opening 181 is provided instead of the opening 75 in Figure 6. In this example, the opening 181 is made up of one large opening. In this example, the opening ratio can be adjusted to the desired size by adjusting the size (area) of the opening portion that becomes the opening 181, and this adjustment can be easily performed.

[0121] The example shown in Figure 16 is the same as the example shown in Figure 6. In this example, multiple openings (small openings) are provided periodically in the portion of the vehicle sheet metal 74 facing the passive radiator 73, and the portion consisting of these multiple openings constitutes the opening 75.

[0122] In the example shown in Figure 16, the opening ratio can be adjusted to the desired size by adjusting the size (area) and number of each small opening. Furthermore, this example provides higher dustproof and waterproof performance compared to the example shown in Figure 15.

[0123] The example shown in Figure 17 is a combination of the examples shown in Figure 15 and Figure 16. In this example, when viewed from top to bottom in the figure, there are no openings in the vehicle sheet metal 74 near the outer circumference of the passive radiator 73, and multiple openings (small openings) are periodically provided only in the area near the center of the passive radiator 73. The area consisting of these multiple openings constitutes the opening 191.

[0124] As described above, when installing the speaker system 61, the opening ratio of the opening provided in the vehicle sheet metal 74 for forming the second air chamber 132 can be adjusted. In particular, even if it is not possible to secure a 100% opening ratio for the speaker system 61, if an opening ratio of 30% or more can be secured, the speaker system 61 can be operated with sufficient characteristics.

[0125] Furthermore, as shown in Figure 18, possible installation locations for the speaker system 61 described above include, for example, the front center console or the floor of the luggage compartment inside the vehicle 211.

[0126] The front center console is the space located at the bottom of the space between the seats on the left and right sides at the front of the vehicle interior. In this example, the speaker system 61 is positioned in the front center console area such that the passive radiator 73 is at the bottom of the diagram, facing an opening in the floor of the vehicle interior.

[0127] Similarly, in this example, in the luggage compartment located at the rear of the vehicle, the speaker system 61 is positioned so that the passive radiator 73 faces the opening located at the bottom of the luggage compartment, i.e., the floor portion of the luggage compartment.

[0128] When the speaker system 61 is installed in these locations, the volume of space required for the installation of the speaker system 61 is generally 10L (10 liters) or less.

[0129] For example, in a sealed subwoofer with an air chamber volume of 10 liters, it is difficult to ensure a sufficiently wide reproducible frequency range on the low-frequency side. Furthermore, when installing a FAS (Functional Air Supply System) in a vehicle, it is difficult to obtain sufficient waterproofing and dustproofing performance, as the waterproofing function from under the floor may be compromised.

[0130] In contrast, the speaker system 61 of this technology can secure a sufficient reproducible frequency range in the low-frequency range even in a small installation space, while also achieving sufficient waterproof and dustproof performance. In other words, this technology makes it possible to obtain a speaker system with a sufficiently wide reproducible frequency range in the low-frequency range and sufficient waterproof and dustproof performance, even in a compact configuration.

[0131] In Figure 18, an example was shown in which the speaker system 61, particularly the passive radiator 73, is installed facing downwards, i.e., towards the floor. However, the speaker system 61 can be installed in any orientation.

[0132] For example, the speaker system 61, particularly the passive radiator 73, may be arranged horizontally in the figure. In this case, the passive radiator 73 will be installed facing the wall surface that forms the passenger compartment of the vehicle 211. In this case, an opening 75 will be provided in the wall surface of the vehicle 211.

[0133] In this specification, a system means one component or a collection of multiple components (devices, modules (parts), etc.). In the case of a collection of multiple components, it is not necessary whether all components are housed in the same enclosure. Therefore, a device or the like that houses multiple modules within a single enclosure is a system.

[0134] The components (blocks) of the apparatus illustrated in this specification are functional conceptual blocks, and the actual apparatus does not need to have the illustrated configuration. That is, the apparatus can have any configuration in which the functions of the illustrated components are divided into any units and / or integrated, for example, a configuration having one block in which the functions of all components are integrated.

[0135] Furthermore, the embodiments of this technology are not limited to those described above, and various modifications are possible without departing from the spirit of this technology.

[0136] Furthermore, this technology can also be configured as follows:

[0137] (1) A speaker system comprising a speaker unit having a diaphragm and vibrating the diaphragm to produce sound, and a vibrating member, wherein the space surrounded by the diaphragm and the vibrating member is sealed. (2) The speaker system according to (1), wherein the space surrounded by the diaphragm and the vibrating member functions as a first air chamber, and a space adjacent to the first air chamber and on the opposite side of the diaphragm from the vibrating member functions as a second air chamber. (3) The speaker system according to (2), wherein the volume of the first air chamber is smaller than the volume of the second air chamber. (4) The speaker system according to any one of (1) to (3), wherein the vibrating member has a waterproof function. (5) The speaker system according to any one of (1) to (4), wherein the vibrating member vibrates in phase with the diaphragm in a predetermined frequency band. (6) The area of ​​the vibrating member is the same as or substantially the same as the area of ​​the diaphragm, the speaker system according to any one of (1) to (5). (7) The shape of the vibrating member is the same as or substantially the same as the shape of the diaphragm, the speaker system according to any one of (1) to (6). (8) The vibrating member is fixed in a state in which it can vibrate by a support member connected to the outer circumference of the vibrating member, the speaker system according to any one of (1) to (7). (9) The diaphragm and the vibrating member are formed of the same material, the speaker system according to any one of (1) to (8). (10) The speaker system according to (2), wherein the speaker unit is located in a predetermined space, and the vibrating member is arranged in the predetermined space adjacent to an opening that connects the predetermined space to another space. (11) The speaker system according to (10), wherein the other space functions as the second air chamber. (12) The speaker system according to (10) or (11), wherein the predetermined space is a space inside the vehicle and the other space is a space outside the vehicle. (13) The speaker system according to any one of (10) to (12), wherein the opening ratio of the opening to the vibrating member is greater than or equal to a predetermined value. (14) The speaker system according to (13), wherein the predetermined value is 30%.(15) The speaker system is an in-vehicle speaker system as described in any one of (1) to (14). (16) The speaker system functions as a subwoofer as described in any one of (1) to (15).

[0138] 61 Speaker system, 71 Speaker unit, 72 Frame, 73 Passive radiator, 74 Vehicle sheet metal, 75 Opening, 88 Diaphragm, 101 Vibrating member, 102 Edge

Claims

1. A speaker system comprising a speaker unit having a diaphragm and vibrating the diaphragm to produce sound, and a vibrating member, wherein the space enclosed by the diaphragm and the vibrating member is sealed.

2. The speaker system according to claim 1, wherein the space enclosed by the diaphragm and the vibrating member functions as a first air chamber, and the space adjacent to the first air chamber and on the opposite side from the diaphragm as viewed from the vibrating member functions as a second air chamber.

3. The speaker system according to claim 2, wherein the volume of the first air chamber is smaller than the volume of the second air chamber.

4. The speaker system according to claim 1, wherein the vibrating member has a waterproof function.

5. The speaker system according to claim 1, wherein the vibrating member vibrates in phase with the diaphragm in a predetermined frequency band.

6. The speaker system according to claim 1, wherein the area of ​​the vibrating member is the same as or substantially the same as the area of ​​the diaphragm.

7. The speaker system according to claim 1, wherein the shape of the vibrating member is the same as or substantially the same as the shape of the diaphragm.

8. The speaker system according to claim 1, wherein the vibrating member is fixed in a state in which it can vibrate by a support member connected to the outer circumference of the vibrating member.

9. The speaker system according to claim 1, wherein the diaphragm and the vibrating member are formed of the same material.

10. The speaker system according to claim 2, wherein the speaker unit is located in a predetermined space, and the vibrating member is arranged in the predetermined space adjacent to an opening that connects the predetermined space to another space.

11. The speaker system according to claim 10, wherein the other space functions as the second air chamber.

12. The speaker system according to claim 10, wherein the predetermined space is a space inside the vehicle, and the other space is a space outside the vehicle.

13. The speaker system according to claim 10, wherein the opening ratio of the opening with respect to the vibrating member is greater than or equal to a predetermined value.

14. The speaker system according to claim 13, wherein the predetermined value is 30%.

15. The speaker system according to claim 1, wherein the speaker system is an in-vehicle speaker system.

16. The speaker system according to claim 1, wherein the speaker system functions as a subwoofer.

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