Audio devices

Abstract

To provide an acoustic device capable of obtaining an excellent acoustic effect to normally emphasize a low-tone range even when a vertical position of ears of a listener is changed.SOLUTION: In an on-vehicle acoustic device 1, a left-side speaker unit and a right-side speaker unit 20R are stored inside a case 2 positioned behind a listener. Sound-producing opening parts 15L, 15R for outputting sound pressure issued forward from the speaker units and bass reflex ports 17L, 17R communicating with air chambers on which the backward sound pressure of the speaker units work are formed inside the case 2. An opening dimension H1 of the sound-producing opening parts 15L, 15R in a vertical direction is greater than an opening dimension W1 in a lateral direction. An opening dimension H2 of the bass reflex ports 17L, 17R in the vertical direction is greater than an opening dimension W2 in the lateral direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an acoustic device that applies sound pressure to a listener sitting on a seat such as in an automobile.

Background Art

[0002] Patent Document 1 describes a speaker device incorporated in a backrest portion or a headrest of a chair. In this speaker device, a housing portion having a space with a predetermined volume inside is incorporated in the backrest portion or the headrest, and a speaker unit that converts an electrical signal into sound is installed in a hole formed in front of the housing portion. A tubular duct is connected to the housing portion, and this tubular duct acts as a bass reflex duct, and functions as a bass reflex type speaker as a whole.

[0003] In what is shown in FIG. 3 of Patent Document 1, a tubular duct extends upward from the speaker unit, and the duct end is directed toward the listener's ear. In what is shown in FIG. 5, the speaker unit is located slightly below the listener's ear, and the duct ends of the tubular duct are located side by side on the outer side in the lateral direction of the speaker unit. In paragraph

[0031] and below, in the structure of FIG. 5, the path length of the mid-high frequency from the speaker unit to the external ear inlet and the path length of the bass from the duct end to the external ear inlet are substantially equal, whereas in the structure of FIG. 3, the path length from the duct end to the external ear inlet is shorter than the path length from the speaker unit to the external ear inlet, so it is explained that the sound pressure level of the bass can be increased.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] As described in paragraph

[0031] and subsequent paragraphs of Patent Document 1, in a bass reflex speaker, the audible bass sound pressure level changes depending on the path length from the sound pressure emitted from the duct end to the ear inlet. However, the speaker device described in Patent Document 1 has a circular opening at the duct end, and its opening area is small. Therefore, if the height of the ear inlet differs due to differences in the seating height of the listener or the position of the ear inlet on the listener's head, or if the listener changes their seating posture and changes the height of the ear inlet, the path length of the bass from the duct end to the ear inlet changes significantly. As a result, the audible bass sound pressure level will differ depending on the listener, or the bass sound pressure level will differ depending on the seating posture, making it impossible to obtain the best acoustics intended for a bass reflex speaker.

[0006] The present invention aims to solve the above-mentioned conventional problems and to provide an acoustic device that can effectively deliver sound as a bass reflex speaker even when the position of the listener's ears changes while seated in a car seat or the like. [Means for solving the problem]

[0007] The present invention comprises a case and a case installed in the case vinegar In an acoustic device having a speaker unit, When the direction the listener's face is facing is defined as the front, the opposite side as the back, the direction in which the listener's left and right ears are aligned is defined as the side, and the direction perpendicular to both the front and side is defined as the up and down direction, The case is located behind the listener, and the speaker unit is positioned with its sound-producing direction facing forward. And, The case is provided with an air chamber on which the air vibrations at the back of the speaker unit act, and a bass reflex port that opens forward and is connected to the air chamber. The speaker unit, the air chamber, and the bass reflex port are each provided in pairs so as to be symmetrical in the lateral direction. The case is provided with a head-facing section that faces the listener's head from behind, a sound-producing space section in front of each speaker unit where air vibrations act, and sound-producing openings that open to both sides of the head-facing section in the lateral direction, passing through the sound-producing space section, and each bass reflex port opens outward in the lateral direction of the sound-producing opening. The sound-producing opening has a vertical opening dimension that is larger than the horizontal opening dimension. The aforementioned bass reflex port too The vertical opening dimension is larger than the horizontal opening dimension. The difference between the vertical opening dimension of the sound-producing opening and the vertical opening dimension of the bass reflex port is 10% or less of the larger of the two. It is characterized by the following:

[0010] Furthermore, the sound device of the present invention comprises a case and a device installed in the case vinegar In an acoustic device having a speaker unit, When the direction the listener's face is facing is defined as the front, the opposite side as the back, the direction in which the listener's left and right ears are aligned is defined as the side, and the direction perpendicular to both the front and side is defined as the up and down direction, The case is located behind the listener, and the speaker unit is positioned with its sound-producing direction facing forward. And, The case is provided with an air chamber on which the air vibrations on the back of the speaker unit act, and a passive vibrator that operates in response to the pressure of the air chamber. The speaker unit, the air chamber, and the passive vibrator are each provided in pairs such that they are symmetrical in the lateral direction. The case is provided with a head-facing portion that faces the listener's head from behind, a sound-producing space portion on which the air vibrations in front of each speaker unit act, and sound-producing openings that open to both sides of the head-facing portion in the lateral direction, and each of the passive vibrators is located on the lateral side of the sound-producing openings. The sound-producing opening has a vertical opening dimension that is larger than the horizontal opening dimension. The aforementioned passive vibrator too The vertical dimension is larger than the horizontal dimension. The difference between the vertical opening dimension of the sound-producing opening and the vertical dimension of the passive vibrator is 10% or less of the larger of the two. It is characterized by the following: [Effects of the Invention]

[0013] The acoustic device of the present invention has a bass reflex port or passive vibrator that is elongated in the vertical direction. Therefore, even if the height of the ears differs due to differences in the sitting height of the listener or the position of the ears on the listener's head, or if the height of the ears changes when the listener changes their sitting posture, extreme changes in the sound pressure level of the bass being heard can be suppressed, and the best possible acoustics can always be obtained. [Brief explanation of the drawing]

[0014] [Figure 1] A perspective view of the listener's head and the in-vehicle sound device, which is a first embodiment of the sound device of the present invention, viewed from the front at an oblique angle. [Figure 2] A plan view showing the listener's head and the in-vehicle acoustic device of the first embodiment. [Figure 3] Figure 1 is a perspective view of the in-vehicle audio system, seen from the front at an oblique angle. [Figure 4]Partial cross-sectional perspective view of the in-vehicle audio device shown in FIG. 3 cut along a plane including the IV-IV line, [Figure 5] Partial longitudinal cross-sectional view of the in-vehicle audio device shown in FIG. 1 cut along a plane including the V-V line, [Figure 6] Perspective view of the in-vehicle audio device, which is the second embodiment of the audio device of the present invention, seen from the obliquely front, [Figure 7] Partial cross-sectional perspective view of the in-vehicle audio device shown in FIG. 6 cut along a plane including the VII-VII line, [Figure 8] Diagram for explaining the acoustic effect of the in-vehicle audio device of the first embodiment, [Figure 9] Diagram for explaining the acoustic effect of the comparative example,

Embodiments for Carrying Out the Invention

[0015] In FIGS. 1 to 5, an in-vehicle audio device 1 is shown as the first embodiment of the audio device of the present invention. The in-vehicle audio device 1 has a case 2. The case 2 is a headrest located at the upper part of the seat back of the seat in the automobile, or constitutes a part of the headrest by being embedded in the headrest or the like. In FIGS. 1 and 2, the head H of the listener, who is an occupant of the automobile, is shown. Note that the audio device of the present invention may be installed in a seat equipped in a vehicle such as a train other than an automobile, or may be installed in a seat equipped in a home, a theater, or the like.

[0016] In the in-vehicle audio device 1, the Z1-Z2 direction is the front-rear direction, the Z1 direction is the front, and the Z2 direction is the rear. The direction in which the face F of the listener faces is the front (Z1 direction), and the portion located in the rear (Z2 direction) is the back. The X1-X2 direction is the lateral direction, and the direction in which the left and right ears E, E of the listener are arranged is the lateral direction. The X1 direction is the left direction, and the X2 direction is the right direction. The Y1-Y2 direction is the vertical direction, the Y1 direction is the upper side, and the Y2 direction is the lower side. The Y1-Y2 direction is orthogonal to both the front-rear direction (Z1-Z2 direction) and the lateral direction (X1-X2 direction).

[0017] Figures 1 to 3 show the overall structure of the in-vehicle acoustic device 1. As shown in Figure 2, the inside of the case 2 is provided with left and right partition walls 3 that are formed parallel to the YZ plane at a position that divides the case in the left-right direction (X1-X2 direction). Figures 1 and 3 show a center line O that extends vertically through a portion of the left and right partition walls 3. The in-vehicle acoustic device 1 is divided into a left acoustic section 10L in the left half and a right acoustic section 10R in the right half, relative to the left and right partition walls 3. The left acoustic section 10L and the right acoustic section 10R have a structure that is line-symmetrical with respect to the center line O in the left-right direction and plane-symmetrical with respect to the left and right partition walls 3 in the left-right direction.

[0018] As shown in Figures 1 to 3, a head-facing portion 4 is formed at the front of Case 2, facing the listener's head H from the back. As shown in Figure 2, a cushion portion 5 is provided in front of the head-facing portion 4, allowing the listener to rest their head H against it.

[0019] Case 2 is assembled from multiple parts injection-molded from synthetic resin material, or from multiple parts die-cast from light metal material. As shown in Figures 3 and 4, in the left acoustic section 10L, a front-to-back partition wall 11L is provided inside Case 2, located to the left of the left-to-right partition wall 3, and a portion of the front-to-back partition wall 11L closest to the left-to-right partition wall 3 serves as a speaker support section 12L. The left speaker unit 20L is fixed to the speaker support section 12L.

[0020] As shown in Figure 4, the speaker unit 20L has a frame 21 fixed to a speaker support 12L. A magnetic circuit section 22 is fixed to the rear of the frame 21, and a cone-shaped diaphragm 23 is supported at the front by an edge member 24 and a damper member 25 so as to be able to vibrate freely in the front-rear direction. A bobbin 26 extending to the rear is fixed to the diaphragm 23, and a voice coil 27 wound on the bobbin 26 is located within the magnetic gap of the magnetic circuit section 22. In the speaker unit 20L, the diaphragm 23 is vibrated back and forth by the voice current supplied to the voice coil 27, generating sound pressure (air vibration) in front of (Z1 direction) and behind (Z2 direction) the diaphragm 23.

[0021] The right acoustic section 10R is also provided with front and rear partitions 11R, and a portion of the front and rear partitions 11R forms a speaker support section 12R. The frame 21 of the right speaker unit 20R is fixed to the speaker support section 12R. The right speaker unit 20R is the same as the left speaker unit 20L, and in the speaker unit 20R as well, the frame 21 supports the magnetic circuit section 22 and the diaphragm 23, etc.

[0022] As shown in Figures 2 and 4, in the left acoustic section 10L, the interior of the case 2 is divided into an air chamber 13L at the rear (Z2 direction) of the front-rear partition wall 11L and a sound-producing space 14L at the front (Z1 direction). Air vibrations emitted forward from the speaker unit 20L act on the sound-producing space 14L, and air vibrations emitted backward act on the air chamber 13L. In the right acoustic section 10R, the interior of the case 2 is also divided into a rear air chamber 13R and a front sound-producing space 14R by the front-rear partition wall 11R.

[0023] As shown in Figure 2, the speaker support 12L in the left acoustic section 10L is tilted clockwise in a plan view, and the sound generation direction (direction of air vibration generation) VL of the speaker unit 20L is slightly tilted to the left (X1 direction) relative to the front (Z1 direction). The speaker support 12R of the right acoustic section 10R is tilted counterclockwise in a plan view, and the sound generation direction VR of the speaker unit 20R is slightly tilted to the right (X2 direction) relative to the front (Z1 direction). Even when the sound generation directions VL and VR are directed slightly diagonally from the front, this direction is described as "forward." In other words, "forward" in this specification includes not only the state where it is precisely directed in the Z1 direction, but also directions that are tilted to either the left or right from the Z1 direction.

[0024] As shown in Figures 2, 3, and 4, in the left acoustic section 10L, the sound-producing opening 15L leading to the sound-producing space section 14L opens forward, and in the right acoustic section 10R, the sound-producing opening 15R leading to the sound-producing space section 14R also opens forward. The sound-producing opening 15L opens to the left and outward of the head-facing section 4 of case 2, and the sound-producing opening 15R opens to the right and outward of the head-facing section 4 of case 2.

[0025] As shown in Figures 2 and 4, in the left acoustic section 10L, a duct 16L is provided that extends along the inside of the left wall 2L of case 2 to the inside of the rear wall 2B, and the rear opening 18L of the duct 16L leads to the air chamber 13L. On the front of case 2, the duct 16L opens forward, and this opening serves as the left bass reflex port 17L. In the right acoustic section 10R, a duct 16R is also formed that extends along the inside of the right wall 2R of case 2 to the inside of the rear wall 2B. The rear opening 18R of the duct 16R leads to the air chamber 13R. The duct 16R opens forward, and this opening serves as the right bass reflex port 17R.

[0026] As shown in Figure 3, the left sound-producing opening 15L and the right sound-producing opening 15R have a vertical opening dimension H1 that is larger than the horizontal opening dimension W1. The bass reflex port 17L, located to the left and outside of the sound-producing opening 15L, and the bass reflex port 17R, located to the right and outside of the sound-producing opening 15R, have a vertical opening dimension H2 that is larger than the horizontal opening dimension W2. The vertical opening dimensions H1 of the sound-producing openings 15L and 15R and H2 of the bass reflex ports 17L and 17R are approximately equal. Here, "approximately equal" means that the difference between dimension H1 and dimension H2 is 10% or less of the larger of H1 and H2 (H1 is larger in Figure 3), and preferably 5% or less.

[0027] The in-vehicle audio device 1 functions as a so-called bass reflex speaker by providing bass reflex ports 17L and 17R. The duct 16L of the left acoustic section 10L and the duct 16R of the right acoustic section 10R have a constant cross-sectional area along their entire length in the depth direction. In a bass reflex speaker, the resonant frequency in the low-frequency range is determined by the cross-sectional area and depth of the ducts 16L and 16R and the volume of the air chambers 13L and 13R, allowing the bass reflex ports 17L and 17R to emit air vibrations that emphasize bass frequencies forward. The lateral opening dimension W2 of the bass reflex ports 17L and 17R is determined by setting the cross-sectional area of ​​the ducts 16L and 16R to a desired value, but the lateral opening dimension W2 can be made considerably narrower by increasing the vertical opening dimension H2. As a result, the lateral opening dimension W1 of the sound-producing openings 15L and 15R, which are formed further inward, can be widened, allowing sound pressure (air vibration) from the speaker units 20L and 20R to be effectively delivered to the listener's ears E and E at a high level.

[0028] Next, the operation of the in-vehicle sound device 1 will be explained. Separate drive signals generated based on a stereo sound source are applied to the left speaker unit 20L and the right speaker unit 20R, causing the diaphragms 23 of speaker unit 20L and speaker unit 20R to vibrate in the front-back direction. The sound pressure (air vibration) emitted in the sound-producing direction VL by the vibration of the diaphragm 23 of speaker unit 20L acts on the listener's left ear E through the sound-producing space 14L and the sound-producing opening 15L. Similarly, the sound pressure emitted in the sound-producing direction VR by the vibration of the diaphragm 23 of speaker unit 20R acts on the listener's right ear E through the sound-producing space 14R and the sound-producing opening 15R.

[0029] In the air chamber 13L from the speaker unit 20R, air vibrations are generated in the direction of sound production VR and air vibrations that become back pressure with inverted phase. Due to the vibrations of the air in the air chamber 13L and the air in the duct 16L, a sound pressure with inverted phase and emphasized low frequencies is emitted forward from the left bass reflex port 17L and delivered to the left ear E. Similarly, in the right acoustic section 10R, a sound pressure with emphasized low frequencies emitted from the right bass reflex port 17R is delivered to the right ear E.

[0030] The bass-reflex type speaker's bass-emphasizing acoustic effect is influenced by the balance between the distance L1 from the center of the diaphragm 23 of the speaker units 20L, 20R to the sound-sensing part of the ear E, and the distance L2 from the bass-reflex ports 17L, 17R to the sound-sensing part of the ear E (see Figure 2 for L1 and L2). The in-vehicle acoustic device 1 is designed to produce an optimal acoustic effect that emphasizes the low-frequency range by appropriately balancing the resonant frequency, which is determined by the cross-sectional area and depth of the ducts 16L, 16R and the volume of the air chambers 13L, 13R, with the aforementioned distances L1 and L2 in the lateral direction (X1-X2 direction). Moreover, as shown in Figure 3, the vertical opening dimensions H1 of the sound-producing openings 15L, 15R and the vertical opening dimensions H2 of the bass-reflex ports 17L, 17R are both elongated in the vertical direction, and the opening dimensions H1 and H2 are approximately equal. Therefore, even if the height of ear E changes vertically, the relationship between distance L1 and distance L2 on the plane shown in Figure 2 can always be maintained, allowing for emphasis on the low-frequency range regardless of the height of ear E, and furthermore, a well-balanced acoustic effect can be obtained across all frequency bands.

[0031] Figure 5 shows the relative position of the in-vehicle sound device 1 and the left ear E of the listener when the position of the listener's ear E changes in the vertical direction (Y1-Y2 direction). In Figure 5, (i) indicates the position of the right ear E, which is opposite the center of the vertical opening dimension H1 of the sound-producing opening 15R. When ear E is in position (i), B is the shortest distance from the center of the diaphragm 23 of the speaker unit 20R to the sound-sensing part of the right ear E. (ii) indicates the position of ear E when the straight line connecting the center of the diaphragm 23 to the sound-sensing part of ear E passes the upper end of the sound-producing opening 15R. When ear E is in position (ii), A is the shortest distance from the center of the diaphragm 23 to the sound-sensing part of ear E.

[0032] If D is the vertical distance between ear positions (i) and (ii), then A = √(B 2 +D 2 ) The surface area of ​​the sphere with radius B that includes the sound-sensing part of ear E at position (i) is SB = 4πB 2 Therefore, the surface area of ​​the sphere with radius A that includes the sound-sensing part of ear E at position (ii) is SA = 4πA 2 Therefore, the difference x between the level of sound pressure emitted forward from speaker unit 20R at position (i) and the level at position (ii) can be obtained by the following equation. [Mathematics 1] x = log(4πA) 2 )-log(4πB 2 )

[0033] Generally, when the difference in sound pressure levels exceeds 1.5 dB, the human ear becomes more likely to perceive that difference. If the vertical opening dimension H1 of the sound-producing openings 15L and 15R is 12 cm (D=6 cm), then if B is 10 cm or more, the difference in sound pressure level between position (i) and position (ii) can be kept to 1.5 dB or less. In this embodiment, H1 and H2 are 12 cm (H1 ≈ H2 = 12 cm), and B is 14 cm.

[0034] Figure 8 shows the changes in sound pressure levels at positions (i), (ii), and (iii), where position (iii) is defined as ear E when the straight line connecting the center of the diaphragm 23 to the sound-sensing part of ear E passes the lower end of the sound-producing opening 15R. Figure 8 is a logarithmic graph, with the horizontal axis representing the frequency (Hz) of the sound pressure (air vibration) emitted from the speaker unit, and the vertical axis representing the sound pressure level (dB) measured at positions (i), (ii), and (iii). The in-vehicle acoustic device 1 used for the measurement has H1 and H2 at 12 cm and B at 14 cm.

[0035] As shown in Figure 8, if H1 and H2 are 12 cm and B is 14 cm, then even if the position of ear E moves to any of positions (i), (ii), or (iii), the difference in the level of sound pressure perceived by ear E is almost negligible. Furthermore, since the bass reflex ports 17L and 17R have a large vertical opening dimension H2, and the sound-producing openings 15L and 15R have a large vertical opening dimension H1, the relative positions of the speaker units 20L and 20R and the bass reflex ports 17L and 17R, as viewed in the plane of Figure 2, do not change even if the position of ear E moves to any of positions (i), (ii), or (iii). In other words, the ratio of the straight-line distance L1 from the speaker units 20L and 20R to ear E and the straight-line distance L2 from the bass reflex ports 17L and 17R to ear E, as viewed in the plane, does not change. Therefore, as shown in Figure 8, regardless of the position of ear E (i), (ii), or (iii), it is possible to obtain sound with emphasized low frequencies.

[0036] Figure 9 shows the acoustic effects of the comparative example. In the comparative example, the same in-vehicle acoustic device 1 used to measure the acoustic effects shown in Figure 8 was used, but the lower half (Y2 side) of both the sound-producing openings 15L, 15R and the bass reflex ports 17L, 17R was blocked. Ear E was positioned at the upper position (ii) shown in Figure 5, and at the lower position (iii), where the straight line connecting the center of the diaphragm 23 to the sound-sensing part of ear E passes the lower end of the sound-producing opening 15R. The sound pressure levels at positions (ii) and (iii) were measured. As shown in Figure 9, in the comparative example, the sound pressure level at position (iii) is affected by a change in the timing of phase inversion in the low-frequency range, resulting in an imbalance between the low-frequency and mid-high-frequency ranges. Furthermore, even in the high-frequency range, there is a difference of about 10 dB in sound pressure levels between position (ii) and position (iii).

[0037] In contrast, in the in-vehicle sound device 1 of the embodiment of the present invention, as shown in Figure 8, there is almost no difference in sound pressure level regardless of whether the position of the ear E is (i), (ii), or (ii). Moreover, regardless of whether the position is (i), (ii), or (ii), the bass reflex speaker can effectively perform its function and obtain an acoustic effect that emphasizes the low frequency range. Therefore, even if there are differences in the sitting height of the seated listener or the position of the ears on the head, or even if the listener changes their sitting posture and the height of the ears changes, good acoustics that emphasize the low frequency range can always be obtained.

[0038] Figures 6 and 7 show an in-vehicle sound device 101, a second embodiment of the sound device of the present invention. The case 102 of the in-vehicle sound device 101 is provided with a head-facing section 104 in the front center. Similar to the interior of case 2 of the in-vehicle sound device 1 shown in Figure 2, the interior of case 102 is divided into a left sound section 110L and a right sound section 110R. Figure 7 shows a part of the left sound section 110L, and the left sound section 110L and the right sound section 110R have a structure that is symmetrical laterally with respect to the center line O.

[0039] As shown in Figure 7, in the left acoustic section 110L, a front and rear partition wall 111L is provided inside the case 102, and a part of the front and rear partition wall 111L forms a speaker support section 112L. The frame 21 of the left speaker unit 20L is fixed to this speaker support section 112L. The speaker unit 20L shown in Figure 7 is the same as the speaker unit 20L shown in Figure 4. In the left acoustic section 110L, the inside of the case 102 is divided by the front and rear partition wall 111L into a rear air chamber 113L and a front sound-producing space section 114L. In the left acoustic section 110L, a sound-producing opening 115L leading to the sound-producing space section 114L opens forward on the side of the head-facing section 104.

[0040] An opening 116L extending in the vertical direction (Y1-Y2 direction) is formed in the front (Z1 direction) portion of the front and rear partition wall 111L. A passive vibrator (passive diaphragm) 117L is provided in the opening 116L. The passive vibrator 117L is located inside the sound-producing space 114L. A damper member 118L is provided between the outer periphery of the passive vibrator 117L and the inner periphery of the opening 116L. The passive vibrator 117L is made of a resin sheet or paper material, and the damper member 118L is made of a thin resin sheet or elastomer sheet, etc., and is configured to have a predetermined modulus of elasticity so that the front and rear positions of the passive vibrator 117L can be restored. The opening 116L is completely closed by the passive vibrator 117L and the damper member 118L. As shown in Figure 6, in the right acoustic section 110R, a passive vibrator 117R and a damper member 118R are provided in an opening 116R formed in the front and rear partition wall 115R inside the sound-producing opening 115R.

[0041] In this in-vehicle acoustic device 101, a sound pressure with inverted phase is applied from the speaker unit 20L to the rear air chamber 113L, and this sound pressure causes a passive vibrator 117L having a predetermined resonant frequency to vibrate. The vibration of the passive vibrator 117L causes a sound pressure with emphasized bass to be emitted forward. From the sound-producing opening 115L, the sound pressure emitted forward from the speaker unit 20L and the sound pressure with emphasized bass due to the vibration of the passive vibrator 117L are emitted forward and delivered to the left ear E. This operation is the same for the right acoustic unit 110R.

[0042] As shown in Figure 6, the left sound-producing opening 115L and the right sound-producing opening 115R have a larger vertical opening dimension H3 (Y1-Y2 direction) than the horizontal opening dimension W3 (X1-X2 direction). The left passive vibrator 117L and the right passive vibrator 117R have a larger vertical dimension H4 than the horizontal dimension W4. The preferred values ​​for the opening dimensions W3 and H3 of the sound-producing openings 115L and 115R of the in-vehicle acoustic device 101 are the same as the opening dimensions W1 and H1 of the sound-producing openings 15L and 15R of the in-vehicle acoustic device 1 shown in Figure 3, and the preferred values ​​for the dimensions W4 and H4 of the passive diaphragms 117L and 117R of the in-vehicle acoustic device 101 are the same as the opening dimensions W2 and H2 of the bass reflex ports 17L and 17R of the in-vehicle acoustic device 1 shown in Figure 3.

[0043] In the in-vehicle acoustic device 101 shown in Figures 6 and 7, the vertical opening dimensions H3 of the sound-producing openings 115L and 115R and the vertical dimensions H4 of the passive vibrators 117L and 117R are almost the same, and both extend considerably in the vertical direction. Therefore, even if the position of the listener's ear E changes vertically, a well-balanced sound pressure effect with an emphasis on the low-frequency range can always be obtained. [Explanation of symbols]

[0044] 1 In-vehicle audio equipment 2 cases 10L left side acoustic section 10R Right side acoustic unit 11L,11R Front and rear walls 12L, 12R Speaker support section 13L, 13R air chamber 14L, 14R Pronunciation Space 15L, 15R sound opening 16L, 16R duct 17L, 17R Bass reflex port 20L, 20R Speaker Unit 101 In-vehicle audio equipment 110L left side acoustic section 110R Right side acoustic section 114L air chamber 115L, 115R sound opening 117L, 117R Passive Vibrator 118L, 118R damper components O center line

Claims

1. In an acoustic device having a case and a speaker unit installed in the case, When the direction the listener's face is facing is defined as the front, the opposite side as the back, the direction in which the listener's left and right ears are aligned is defined as the side, and the direction perpendicular to both the front and side is defined as the up and down direction, The case is located behind the listener, the speaker unit is installed with its sound-producing direction facing forward, the case is provided with an air chamber through which the air vibrations from the back of the speaker unit act, and a bass reflex port that opens forward and is connected to the air chamber, and the speaker unit, the air chamber, and the bass reflex port are each provided in pairs so as to be symmetrical in the lateral direction. The case is provided with a head-facing section that faces the listener's head from behind, a sound-producing space section in front of each speaker unit where air vibrations act, and sound-producing openings that open to both sides of the head-facing section in the lateral direction, passing through the sound-producing space section, and each bass reflex port opens outward in the lateral direction of the sound-producing opening. The sound-producing opening has a vertical opening dimension greater than its horizontal opening dimension, the bass reflex port also has a vertical opening dimension greater than its horizontal opening dimension, and the difference between the vertical opening dimension of the sound-producing opening and the vertical opening dimension of the bass reflex port is 10% or less of the larger of the two.

2. In an acoustic device having a case and a speaker unit installed in the case, When the direction the listener's face is facing is defined as the front, the opposite side as the back, the direction in which the listener's left and right ears are aligned is defined as the side, and the direction perpendicular to both the front and side is defined as the up and down direction, The case is positioned behind the listener, the speaker unit is installed with its sound-producing direction facing forward, and the case is provided with an air chamber on which the air vibrations from the back of the speaker unit act, and a passive vibrator that operates in response to the pressure of the air chamber, and the speaker unit, the air chamber, and the passive vibrator are each provided in pairs so as to be symmetrical in the lateral direction. The case is provided with a head-facing portion that faces the listener's head from behind, a sound-producing space portion on which the air vibrations in front of each speaker unit act, and sound-producing openings that open to both sides of the head-facing portion in the lateral direction, and each of the passive vibrators is located on the lateral side of the sound-producing openings. The sound-producing opening has a vertical opening dimension greater than its horizontal opening dimension, the passive vibrator also has a vertical dimension greater than its horizontal dimension, and the difference between the vertical opening dimension of the sound-producing opening and the vertical dimension of the passive vibrator is 10% or less of the larger of the two.

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