CN220755030U - Acoustic output device - Google Patents

Acoustic output device Download PDF

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CN220755030U
CN220755030U CN202321538845.7U CN202321538845U CN220755030U CN 220755030 U CN220755030 U CN 220755030U CN 202321538845 U CN202321538845 U CN 202321538845U CN 220755030 U CN220755030 U CN 220755030U
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acoustic
sound
field
port
cavity
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王真
梁家宁
张磊
齐心
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Shenzhen Voxtech Co Ltd
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Shenzhen Voxtech Co Ltd
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Abstract

The embodiments of the present disclosure provide at least one acoustic driver, a first cavity and a second cavity acoustically coupled to the at least one acoustic driver, the first cavity having a first acoustic aperture and the second cavity having a second acoustic aperture, the at least one acoustic driver radiating sound having a phase difference to the outside through the first acoustic aperture and the second acoustic aperture, wherein near-field sound radiated from the first acoustic Kong Fu and near-field sound radiated from the second acoustic Kong Fu have a near-field sound pressure level difference of less than 6dB in a target frequency band, and the acoustic output device exhibits directivity to sound radiated to the far field in the target frequency band as if the sound radiated from the first acoustic aperture and the second acoustic Kong Fu have a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions.

Description

Acoustic output device
Cross reference
The present application claims priority from international application No. PCT/CN2023/083553 filed 24 at 3 month 2023, and international application No. PCT/CN2023/083554 filed 24 at 3 month 2023, the entire contents of which are incorporated herein by reference.
Technical Field
The present disclosure relates to the field of acoustics, and in particular, to an acoustic output device.
Background
During the process of outputting sound, most sound waves radiate to the auditory meatus of the user, and part of sound waves inevitably radiate in other directions (for example, in directions away from the auditory meatus), which causes certain leakage of sound from the acoustic output device. Thus, in order to reduce the leakage of the acoustic output device, the directional propagation of sound waves by the acoustic output device is of great importance. The existing acoustic output device generally adopts dipoles composed of two sound sources with the same amplitude and opposite phases to form a directional radiation sound field, so that the directional propagation of sound is realized. However, in this way, sound wave propagation in a specific direction is achieved, and a sound field intensity in the opposite direction to the specific direction is also large, which means that when a person is located directly in front of or beside the listener, a noticeable leak sound can be heard.
Therefore, it is necessary to design an acoustic output device to maximize the volume in the direction of the auditory meatus of the listener, and to have less leakage in other directions, so that sound privacy can be better achieved.
Disclosure of Invention
One of the embodiments of the present specification provides an acoustic output device, the device comprising: at least one acoustic driver; a first cavity and a second cavity acoustically coupled to the at least one acoustic driver, a first acoustic hole being provided in the first cavity, a second acoustic hole being provided in the second cavity, the at least one acoustic driver radiating sound having a phase difference to the outside through the first acoustic hole and the second acoustic hole, wherein, in a target frequency band, near-field sound radiated from the first acoustic Kong Fu and near-field sound radiated from the second acoustic Kong Fu have a near-field sound pressure level difference, the near-field sound pressure level difference being less than 6dB, and, in the target frequency band, the acoustic output device exhibits directivity to sound radiated to the far field, exhibiting that sound radiated from the first acoustic hole and the second acoustic Kong Fu have a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions. By controlling the two sounds generated by the acoustic output device to have a phase difference and controlling the near-field sound emitted from the first acoustic Kong Fu and the near-field sound emitted from the second acoustic Kong Fu to have a near-field sound pressure level difference of less than 6dB in the target frequency band and the sound emitted from the first acoustic orifice and the second acoustic Kong Fu to have a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions in the target frequency band, it is possible to make the volume in the direction of the auditory meatus larger, the leakage in the opposite direction of the auditory meatus direction and the leakage in other directions smaller, and it is possible to better compromise the auditory meatus opening and the auditory meatus privacy.
In some embodiments, the target frequency band is 200Hz-5000Hz. Since 200Hz-5000Hz is the primary frequency range to which the human ear is more sensitive, limiting the target frequency band to 200Hz-5000Hz may result in the acoustic output device having less leakage in the primary audible frequency band of the human ear.
In some embodiments, the near field sound pressure level difference is less than 3dB and/or the far field sound pressure level difference is not less than 6dB. By further defining the near-field sound pressure level difference and/or the far-field sound pressure level difference, it may be further ensured that the first sound and the second sound effectively interfere with each other in a specific direction of the far field, thereby effectively reducing the leakage sound of the acoustic output device in the far field.
In some embodiments, the rate of change of the phase difference is less than 30 °/oct over a frequency range of 1kHz-8 kHz. By controlling the rate of change of the near-field phase difference to be less than 30 °/oct, two sound sources can be made to form a more standard strong directional radiation sound field (for example, a heart-type or super-heart-type directional radiation sound field), and leakage sound in the opposite direction to the ear canal direction and leakage sound in other directions are made smaller, so that the ear canal opening and the listening privacy can be better considered.
In some embodiments, the absolute value of the difference between the phase difference at 1kHz and the phase difference at 2kHz of the near-field sound emitted from the first acoustic Kong Fu and the near-field sound emitted from the second acoustic Kong Fu is less than 30 °. Since the frequency range of 1000Hz to 2000Hz is in a frequency range where human ears are more sensitive, based on this, in this frequency range, by controlling the absolute value of the difference between the phase difference at 1000Hz between the sound emitted from the first acoustic Kong Fu and the sound emitted from the second acoustic Kong Fu and the phase difference at 2000Hz within 30 °, the effect of reducing far-field leakage sound can be further improved on the premise of forming a more standard strong directional sound field.
In some embodiments, the target frequency band comprises target frequencies of 500Hz, 1kHz, 2kHz, and 4 kHz. The target frequency band comprises a plurality of discrete frequency points, so that the sound of the acoustic output device at the frequency points can meet the aim of approaching near-field sound pressure and presenting directivity (for example, heart-shaped directivity) in a far-field.
In some embodiments, the ratio of the open area of the first acoustic port to the second acoustic port is in the range of 0.5-2. The ratio of the opening areas of the first acoustic holes to the second acoustic holes is controlled to be 0.5-2, so that acoustic resistances of the first acoustic holes and the second acoustic holes can be close to each other, the near-field sound pressure level difference between the first acoustic holes and the second acoustic holes is reduced, the far-field sound leakage cancellation is more remarkable, and the effect of reducing the far-field sound leakage is improved.
In some embodiments, the difference in acoustic load of the first acoustic port and the second acoustic port is less than 0.15. By controlling the difference value of the acoustic loads of the first acoustic hole and the second acoustic hole to be smaller than 0.15, the acoustic resistances of the first acoustic hole and the second acoustic hole can be close to each other, so that the far-field leakage can be more obviously eliminated, and the effect of reducing the far-field leakage is improved.
In some embodiments, the ratio of the surface acoustic load of the first acoustic port to the second acoustic port is in the range of 0.5-3.5. By controlling the ratio of the surface acoustic loads of the first acoustic hole to the second acoustic hole to be in the range of 0.5-3.5, the acoustic resistances of the first acoustic hole and the second acoustic hole can be close to each other, so that the far-field leakage can be eliminated more obviously, and the effect of reducing the far-field leakage is improved.
One of the embodiments of the present specification provides an acoustic output device, the device comprising: at least one acoustic driver; the first cavity and the second cavity are acoustically coupled with the at least one acoustic driver, a first acoustic hole is formed in the first cavity, a second acoustic hole is formed in the second cavity, the at least one acoustic driver radiates sound with a phase difference to the outside through the first acoustic hole and the second acoustic hole, wherein in a target frequency band, the acoustic output device presents directivity to the sound of far-field radiation, the sound emitted from the first acoustic hole and the second acoustic Kong Fu has a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions, and the difference of the sound loads of the first acoustic hole and the second acoustic hole is less than 0.15. By controlling the two sounds generated by the acoustic output device to have a phase difference and controlling the sounds emitted from the first acoustic port and the second acoustic Kong Fu to have a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions and controlling the difference in sound load of the first acoustic port and the second acoustic port to be less than 0.15, the volume in the direction of the auditory meatus opening of the listener can be made larger, and the leakage in the direction opposite to the direction of the auditory meatus opening of the listener and the leakage in other directions can be made smaller, so that the auditory meatus opening and the auditory privacy can be better considered.
One of the embodiments of the present specification provides an acoustic output device, the device comprising: at least one acoustic driver; the first cavity and the second cavity are acoustically coupled with the at least one acoustic driver, a first acoustic hole is formed in the first cavity, a second acoustic hole is formed in the second cavity, the at least one acoustic driver radiates sound with a phase difference to the outside through the first acoustic hole and the second acoustic hole, wherein in a target frequency band, the acoustic output device presents directivity to the sound of far-field radiation, the sound emitted from the first acoustic hole and the second acoustic Kong Fu has a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions, and the ratio of the surface acoustic load of the first acoustic hole to the surface acoustic load of the second acoustic hole ranges from 0.5 to 3.5. By controlling the two sounds generated by the acoustic output device to have a phase difference and controlling the sounds emitted from the first acoustic port and the second acoustic Kong Fu to have a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions and controlling the ratio of the surface acoustic loads of the first acoustic port and the second acoustic port to be in the range of 0.5 to 3.5, the volume in the direction of the auditory meatus of the listener can be made larger, and the leakage in the opposite direction of the auditory meatus of the listener can be made smaller, so that the auditory meatus openness and the auditory privacy can be better considered.
One of the embodiments of the present specification provides an acoustic output device, the device comprising: at least one acoustic driver; the first cavity and the second cavity are acoustically coupled with the at least one acoustic driver, a first acoustic hole is formed in the first cavity, a second acoustic hole is formed in the second cavity, the at least one acoustic driver radiates sound with a phase difference to the outside through the first acoustic hole and the second acoustic hole, the change rate of the phase difference is smaller than 30 DEG/oct in a frequency range of 1kHz-8kHz, and the sound radiated to the far field by the acoustic output device presents directivity in a target frequency band and is expressed as far-field sound pressure level difference of not smaller than 3dB in at least one pair of opposite directions. By controlling the two sounds generated by the acoustic output device to have a phase difference and to be controlled within a frequency range of 1kHz-8kHz, the rate of change of the near-field phase difference is less than 30 °/oct, and controlling the sound emitted from the first acoustic port and the second acoustic Kong Fu to have a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions, the volume in the direction of the auditory meatus of the listener can be made larger, and the leakage in the direction opposite to the direction of the auditory meatus of the listener and in other directions can be made smaller, so that the auditory meatus openness and the auditory privacy can be better considered.
One of the embodiments of the present specification provides an acoustic output device, the device comprising: at least one acoustic driver; the first cavity and the second cavity are acoustically coupled with the at least one acoustic driver, a first acoustic hole is formed in the first cavity, a second acoustic hole is formed in the second cavity, the at least one acoustic driver radiates sound with a phase difference to the outside through the first acoustic hole and the second acoustic hole, wherein in a target frequency band, the acoustic output device presents directivity to the sound of far-field radiation, the sound emitted from the first acoustic hole and the second acoustic Kong Fu has a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions, and the ratio range of the opening area of the first acoustic hole to the opening area of the second acoustic hole is 0.5-2. By controlling the two sounds generated by the acoustic output device to have a phase difference and controlling the sounds emitted from the first acoustic port and the second acoustic Kong Fu to have a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions and controlling the ratio of the opening areas of the first acoustic port and the second acoustic port to be in the range of 0.5-2, the volume in the direction of the auditory meatus opening of the listener can be made larger, and the leakage in the direction opposite to the direction of the auditory meatus opening of the listener and the leakage in other directions can be made smaller, so that the auditory meatus opening and the auditory meatus privacy can be better considered.
Drawings
The present application will be further illustrated by way of example embodiments, which will be described in detail with reference to the accompanying drawings. The embodiments are not limiting, in which like numerals represent like structures, wherein:
FIG. 1 is a schematic diagram of an exemplary directional radiated sound field of an acoustic output device according to some embodiments of the present description;
FIG. 2A is a block diagram of an exemplary acoustic output device shown in accordance with some embodiments of the present description;
FIG. 2B is a graph of near-field sound pressure level versus frequency for an exemplary first acoustic port and second acoustic port shown in accordance with some embodiments of the present description;
FIG. 3A is a schematic diagram of a directional radiated sound field of an exemplary acoustic output device according to some embodiments of the present description;
FIG. 3B is a schematic diagram of a directional radiated sound field of an exemplary acoustic output device according to other embodiments of the present disclosure;
FIG. 3C is a schematic diagram of a method of calculating distance between acoustic centers according to some embodiments of the present disclosure;
FIG. 4 is an exemplary dual source radiation schematic diagram shown in accordance with some embodiments of the present description;
FIG. 5 is a first sound source AS corresponding to equation (5) 1 And a second sound source AS 2 Phase difference betweenSchematic diagram of the relationship between the frequency f and the spacing l;
FIG. 6 is a schematic diagram of a directional radiated sound field at different frequencies according to some embodiments of the present disclosure;
FIG. 7A is a schematic diagram of an exemplary sounding portion shown according to some embodiments of the present disclosure;
FIG. 7B is a schematic diagram of an exemplary sounding portion according to further embodiments of the present disclosure;
FIG. 7C is a schematic diagram of an exemplary sounding portion according to further embodiments of the present disclosure;
FIG. 8 is another exemplary sounding portion schematic diagram shown in accordance with some embodiments of the present disclosure;
FIG. 9 is another exemplary sounding portion schematic diagram shown in accordance with some embodiments of the present disclosure;
FIG. 10A is another exemplary sounding portion schematic diagram according to some embodiments of the present disclosure;
FIG. 10B is a schematic diagram of the frequency response of the Helmholtz resonator;
FIG. 11 is an exemplary block diagram of a sound emitting portion having two acoustic drivers according to some embodiments of the present description;
fig. 12 is an exemplary block diagram of a sound emitting portion having two acoustic drivers according to other embodiments of the present description.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required to be used in the description of the embodiments will be briefly described below. It is apparent that the drawings in the following description are only some examples or embodiments of the present application, and it is obvious to those skilled in the art that the present application may be applied to other similar situations according to the drawings without inventive effort. Unless otherwise apparent from the context of the language or otherwise specified, like reference numerals in the figures refer to like structures or operations.
It will be appreciated that "system," "apparatus," "unit" and/or "module" as used herein is one method for distinguishing between different components, elements, parts, portions or assemblies of different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.
As used in this application and in the claims, the terms "a," "an," "the," and/or "the" are not specific to the singular, but may include the plural, unless the context clearly dictates otherwise. In general, the terms "comprises" and "comprising" merely indicate that the steps and elements are explicitly identified, and they do not constitute an exclusive list, as other steps or elements may be included in a method or apparatus.
Flowcharts are used in this application to describe the operations performed by systems according to embodiments of the present application. It should be appreciated that the preceding or following operations are not necessarily performed in order precisely. Rather, the steps may be processed in reverse order or simultaneously. Also, other operations may be added to or removed from these processes.
Fig. 1 is a schematic diagram of an exemplary directional radiated sound field of an acoustic output device according to some embodiments of the present description.
The acoustic output device outputs sound near the listener's ears so that the listener hears the sound while also radiating the sound to the surrounding environment, which results in a greater degree of leakage from the acoustic output device. In order to reduce leakage from the acoustic output device so that more sound can be transmitted to the ear canal orifice of the listener, in some embodiments, the acoustic output device may employ two sound sources of equal amplitude and opposite phase (e.g., the first sound source AS shown in FIG. 1) 1 And a second sound source AS 2 ) The dipole 1 is formed, and the dipole 1 can form a directional radiation sound field like an 8 shape as shown in fig. 1. The directional radiation sound field like the "8" shape may include two directions in which radiation is extremely strong, and it is also understood that the directional radiation sound field like the "8" shape has two main lobes. To enhance the listening effect of the listener, the sound that the acoustic output device propagates towards the ear canal opening of the listener can be made sufficiently loud by adjusting the positions of the two sound sources such that one main lobe is directed towards the ear canal opening of the listener. Meanwhile, as can be seen from the schematic diagram of the directional radiation sound field of the dipole 1 in fig. 1, when one main lobe is directed to the ear canal opening R1 of the listener, the other main lobe is generally directed directly in front of or to the side of the listener. This means that when the other person is located in front of or beside the listener, it is also clear The leakage of the acoustic output device is heard clearly.
Since the degree of cancellation of the sound output by the acoustic output device in the far field can be changed by adjusting the phase of the sound output by the acoustic output device, in order to further reduce the leakage of the acoustic output device, the embodiments of the present specification provide an acoustic output device that can radiate sound having a phase difference to the outside. The acoustic output device may include at least one acoustic driver, and first and second cavities coupled with the at least one acoustic driver. The first cavity is provided with a first acoustic hole, the second cavity is provided with a second acoustic hole, and at least one acoustic driver can radiate sound with phase difference to the outside through the first acoustic hole and the second acoustic hole. Further, when the phase difference satisfies a certain condition, it is possible to suppress leakage sound output by the acoustic output device in the opposite direction while maintaining the acoustic output device to output a large sound volume in a certain direction (for example, in the direction in which the user's ear canal is located). In some embodiments, the phase difference may be between 120 ° and 179 °. In some embodiments, the phase difference may be between 90 ° and 179 °.
In some embodiments, by adjusting the phase difference between the two sounds generated by the acoustic output device, the near-field sound emitted from the first acoustic Kong Fu and the near-field sound emitted from the second acoustic Kong Fu can have a near-field sound pressure level difference of less than 6dB in the target frequency band, and the acoustic output device can present directivity to the far-field radiated sound in the target frequency band (the directivity can be represented by the sound emitted from the first acoustic hole and the second acoustic Kong Fu having a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions), so that the volume in the direction of the auditory meatus R1 can be made larger, the leakage sound in the opposite direction of the auditory meatus R1 and the leakage sound in other directions can be made smaller, and the auditory meatus opening and the auditory meatus privacy can be better.
Fig. 2A is a block diagram of an exemplary acoustic output device according to some embodiments of the present description.
In some embodiments, the acoustic output device may include at least one acoustic driver. As shown in fig. 2A, the acoustic output device 100 may include an acoustic driver 121, a first cavity 122, and a second cavity 123. The first cavity 122 and the second cavity 123 are acoustically coupled to the acoustic driver 121, respectively. In some embodiments, the first cavity 122 of the acoustic output device 100 may be provided with a first acoustic hole, and the acoustic driver 121 may radiate sound (also referred to as a first sound) from the first acoustic hole to the outside through the first cavity 122; the second cavity 123 of the acoustic output device 100 may be provided with a second acoustic hole, and the acoustic driver 121 may radiate sound (also referred to as a second sound) from the second acoustic hole to the outside through the second cavity 123.
The acoustic driver 121 is a device capable of converting an electric signal into an acoustic signal and outputting the acoustic signal. Illustratively, the acoustic driver 121 may have a diaphragm and a driving member (e.g., a coil and magnetic circuit assembly) capable of driving the diaphragm into vibration. In some embodiments, the number of acoustic drivers 121 may be one. At this time, the acoustic driver 121 may have front and rear sides, and radiate sound from the front and rear sides to the first and second chambers 122 and 123, respectively. For example, taking the example that the driving member comprises a coil and magnetic circuit assembly, the front side of the acoustic driver 121 may be the side of the diaphragm facing away from the driving member (i.e. there is no driving member at the front side of the acoustic driver 121), and the rear side of the acoustic driver 121 may be the side of the diaphragm facing towards the driving member (i.e. there is a driving member at the rear side of the acoustic driver 121) or the side of the driving member facing away from the diaphragm. During vibration, sounds of equal amplitude and opposite phases are generated at the front and rear sides bounded by the diaphragm. By providing a sound transmission path of sound in the acoustic output device 100, a specific phase difference (for example, a phase difference of 120 ° -179 °) can be made between the first sound emitted from the first acoustic Kong Fu after passing through the first cavity 122 and the second sound emitted from the second acoustic Kong Fu after passing through the second cavity 123. In some embodiments, the first cavity 122 and the second cavity 123 are respectively located at two sides of the diaphragm, and the diaphragm can radiate sound to the first cavity 122 and the second cavity 123 when vibrating. Sound radiated from the diaphragm toward the first cavity 122 may be transferred to the first acoustic port in accordance with the first sound transfer path and radiated outward from the first acoustic port; sound radiated from the diaphragm to the second chamber 123 may be transferred to the second acoustic port in accordance with the second sound transfer path and radiated outward from the second acoustic port. In some embodiments, the phase of the first sound and the second sound may be regulated by providing an acoustic structure of the first cavity 122 and/or the second cavity 123.
In some embodiments, the number of acoustic drivers 121 may be two or more. The two acoustic drivers 121 may be driven by two sets of electrical signals, respectively. The two acoustic drivers 121 may radiate sound to the first and second cavities 122 and 123, respectively. In some embodiments, the amplitude and phase of the sound radiated by the two acoustic drivers 121 to the first and second cavities 122, 123 may be regulated by setting the amplitude and phase of the electrical signals driving the two acoustic drivers 121, thereby regulating the amplitude and phase of the first sound radiated from the first acoustic port via the first cavity 122 and the amplitude and phase of the second sound radiated from the second acoustic port via the second cavity 123. In some embodiments, the phase of the first sound and the second sound may also be regulated by providing an acoustic structure of the first cavity 122 and/or the second cavity 123.
The first and second cavities 122 and 123 may be cavities that are acoustically coupled with the acoustic driver 121. The first and second cavities 122 and 123 may be used to transfer sound generated by the acoustic driver 121. The sound in the first cavity 122 may radiate outward through the first acoustic port and the sound in the second cavity 123 may radiate outward through the second acoustic port. In some embodiments, the number of first acoustic holes and/or second acoustic holes may be one or more. The number of the acoustic holes can be reasonably set according to actual requirements, and the number of the acoustic holes is not particularly limited in the specification.
In some embodiments, the acoustic structures in the cavities (first 122, second 123) may change the phase of sound radiated from the acoustic holes of the cavities. In some embodiments, the acoustic structure of the first cavity 122 and/or the second cavity 123 may be configured to regulate the phase of the first sound radiated by the acoustic driver 121 at the first acoustic port and/or the phase of the second sound radiated by the second acoustic port, thereby regulating the phase difference between the first sound and the second sound and further improving the leakage of the acoustic output device 100. For example, in the case where the front side and the rear side of the acoustic driver 121 generate sounds of opposite phases, respectively, a baffle may be provided in the first cavity 122 and/or the second cavity 123 so that the sound path of the sound propagating in the two cavities is different, so that the change in phase when the first sound propagates in the cavity is different from the second sound, thereby adjusting the phase difference of the first sound and the second sound (i.e., the difference between the phase of the first sound at the first acoustic hole and the phase of the second sound at the second acoustic hole). For another example, a specific acoustic structure may be provided in the first and/or second cavities 122 and 123 to change propagation speeds of the first and second sounds in the cavities, thereby adjusting a phase difference of the first and second sounds. Exemplary specific acoustic structures may include slow acoustic structures that slow the propagation of sound, such as acoustic gauzes, acoustic porous materials, and the like. For another example, an expanding acoustic structure (e.g., an expanding cavity) may be provided in the first and/or second cavities 122, 123 to change the speed of equivalent propagation of the first and second sounds in the cavities, thereby adjusting the phase difference of the first and second sounds. As another example, a sound absorbing structure (e.g., a resonant cavity) may be provided in the first and/or second cavities 122, 123 to adjust the phase difference of the first and second sounds using modulation of the sound around the resonant frequency of the sound absorbing structure. For a specific description of the regulation of the phase difference of the first sound and the second sound by providing the acoustic structure of the first cavity 122 and/or the second cavity 123, see elsewhere in this specification, as shown in fig. 7A-10B and the related description thereof.
In some embodiments, when the number of acoustic drivers 121 is two, the phase difference of the first sound and the second sound may also be adjusted by setting the phase of the electrical signals driving the two acoustic drivers 121.
In some embodiments, when the phase difference between the first sound and the second sound is within a specific range (for example, 120 ° -179 °), even if the near-field sound emitted from the first acoustic Kong Fu and the near-field sound emitted from the second acoustic Kong Fu are close in sound pressure within the target frequency band, the sound radiated to the far field by the acoustic output device 100 can exhibit directivity, so that the radiation field of the sound at the far field has at least one strong directivity direction (the sound pressure in the strong directivity direction and the vicinity thereof is sufficiently large), while the radiation intensities in the other directions are relatively small. For example, the near-field sound radiated from the first and second cavities 122 and 123 has a near-field sound pressure level difference of less than 6dB, and the sound radiated from the first and second cavities 122 and 123 has a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions (for example, a direction toward the ear canal opening R1 and a direction away from the ear canal opening R1 when the acoustic output device 100 is worn by the user). As another example, near-field sound radiated from the first and second cavities 122 and 123 has a near-field sound pressure level difference of less than 3dB, and sound radiated from the first and second cavities 122 and 123 has a far-field sound pressure level difference of not less than 6dB in at least one pair of opposite directions. It can be understood that the smaller the near-field sound pressure level difference is, the more remarkable the sound wave with the same amplitude and opposite phase is counteracted in the far field, and the better the effect of reducing the leakage sound is; further, the greater the far-field sound pressure level difference, the stronger the far-field sound directivity, and the smaller the leakage in the direction away from the ear canal opening (for example, the direction away from the ear canal opening R1) and the leakage in the other directions, that is, the better the effect of reducing the far-field leakage. In some embodiments, the strong directivity direction may be oriented toward the ear canal opening R1 of the user when the acoustic output device 100 is worn by the user. As such, when the acoustic output device 100 is worn by a user, the sound delivered to the user's ear canal orifice R1 may be sufficiently loud, while also reducing leakage in other directions (e.g., away from the ear canal orifice), thereby improving the user's listening experience and privacy.
It should be noted that the phase of the sound radiated from the acoustic holes (including the first acoustic hole and the second acoustic hole) described in the embodiments of the present specification may refer to a phase measured 4mm from the acoustic hole (or the geometric center of the acoustic hole) (for example, 4mm in front of the acoustic hole). In some embodiments, the method of testing the phase difference may be to measure the phases of the sounds (the first sound and the second sound, respectively) emitted from the first acoustic orifice and the second acoustic Kong Fu, respectively, and then calculate the phase difference of the first sound and the second sound. When testing the sound of the first acoustic port (or the second acoustic port), a baffle may be used to separate the first acoustic port from the second acoustic port to avoid the second acoustic port (or the first acoustic port) interfering with the test. Further, the sound collection device can be placed on the connecting line of the first acoustic hole and the second acoustic hole and collect the first sound at a position 4mm away from the first acoustic hole (or the second acoustic hole), so that the second acoustic hole (or the first acoustic hole) is further prevented from interfering with the test. By way of example only, the dimensions of the barrier plate may be selected to be standard. For example, the length, width and height dimensions of the mask may be 1650mm, 1350mm and 30mm, respectively. It should be further noted that when the number of the first acoustic holes (or the second acoustic holes) is two or more, one of the first acoustic holes (or the second acoustic holes) may be selected for testing. For example, a first acoustic port and a second acoustic port located at specific relative positions (e.g., at minimum or maximum relative distances) may be selected, the phases of the sounds emitted by each of them may be tested, and the phase difference calculated. In addition, sound measurement in a specific frequency band (for example, 1000Hz-8000 Hz) is not necessarily realized through exhaustion, but sound of each sampling point can be measured by setting a plurality of (for example, 20-30) frequency sampling points with equal step sizes and end points being frequency band end points.
In some embodiments, the acoustic output device 100 may include a support structure 110 and a sound emitting portion 120, and an acoustic driver 121 and first and second cavities 122 and 123 acoustically coupled to the acoustic driver 121 may be disposed in the sound emitting portion 120.
The sound emitting part 120 may be used to generate and radiate sound outwards. In some embodiments, the acoustic output device 100 may secure the sound emitting portion 120 in a position near the user's ear without occluding the user's ear canal through the support structure 110. In some embodiments, the projection of the sound emitting portion 120 onto the user's ear plane may partially or fully cover but not occlude the user's ear canal. In some embodiments, the projection of the sound emitting portion 120 onto the user's ear plane may also not cover the user's ear canal, thereby enabling the user's ear to remain open. The user's ears are kept in an open state, and the user can hear the sound outputted from the sound emitting part 120 and acquire the sound of the external environment.
The support structure 110 may be used to carry the sound emitting portion 120. In some embodiments, the support structure 110 may be mounted to the user's ear, head, or upper torso while the user wears the acoustic output device 100. In some embodiments, the support structure 110 may include an arc structure that fits the pinna R2 of the user. By way of example only, the arc structure may include, but is not limited to, a hook, a C-shape, and the like. The support structure 110 may be mounted or clamped to the pinna R2 of the user while the user is wearing the acoustic output device 100, thereby enabling the acoustic output device 100 to be worn. In some embodiments, the support structure 110 may also include an ear-hanging structure that fits with the head or upper torso of the user. When the acoustic output device 100 is worn by a user, the ear-hanging structure may be hung on the auricle R2 of the user through the head or neck of the user to realize the wearing of the acoustic output device 100.
In some embodiments, the support structure 110 may be made of a softer material, a harder material, the like, or a combination thereof. A softer material refers to a material having a hardness (e.g., shore hardness) less than a first hardness threshold (e.g., 15A, 20A, 30A, 35A, 40A, etc.). For example, the softer material may have a Shore hardness of 45-85A,30-60D. A harder-textured material refers to a material having a hardness (e.g., shore hardness) greater than a second hardness threshold (e.g., 65D, 70D, 80D, 85D, 90D, etc.). The softer-textured material may include, but is not limited to, polyurethane (PU) (e.g., thermoplastic polyurethane elastomer rubber (Thermoplastic Polyurethanes, TPU)), polycarbonate (PC), polyamide (PA), acrylonitrile-butadiene-styrene copolymer (Acrylonitrile Butadiene Styrene, ABS), polystyrene (PS), high impact Polystyrene (High Impact Polystyrene, HIPS), polypropylene (PP), polyethylene terephthalate (Polyethylene Terephthalate, PET), polyvinyl chloride (Polyvinyl Chloride, PVC), polyurethane (PU), polyethylene (PE), phenolic resin (Phenol Formaldehyde, PF), urea-Formaldehyde resin (UF), melamine-Formaldehyde resin (MF), silica gel, and the like, or combinations thereof. The harder-textured material may include, but is not limited to, polyethersulfone resin (Poly (estersulfones), PES), polyvinylidenechloride (PVDC), polymethyl methacrylate (Polymethyl Methacrylate, PMMA), polyetheretherketone (PEEK), or the like, or combinations thereof, or mixtures thereof with reinforcing agents such as glass fibers, carbon fibers, and the like. In some embodiments, the material of the support structure 110 may be selected according to the specific situation. For example, a softer material may increase the comfort of the user wearing the acoustic output device 100 and the fit to the user's ear, and a harder material may increase the strength of the acoustic output device 100.
In some embodiments, the acoustic output device 100 may also include only the sound emitting portion 120. For example, when the acoustic output device 100 is worn, the sound generating portion 120 may be directly clamped in the ear cavity at a position where the ear canal is not blocked, and the acoustic output device 100 does not need to be provided with the support structure 110 to carry the sound generating portion 120.
In some embodiments of the present disclosure, the phase difference between two sounds generated by the sound generating portion is regulated by the acoustic output device, so that in the target frequency band, the near-field sound emitted by the first acoustic Kong Fu and the near-field sound emitted by the second acoustic Kong Fu are ensured to have a smaller sound pressure level difference, and meanwhile, the directivity of the sound emitted by the acoustic output device to far-field radiation is ensured, so that the sound emitted to the outside through the first acoustic hole and the second acoustic hole can be cancelled in the far field in a specific direction, and therefore, the leakage sound of the far field can be reduced.
The target frequency band may be a frequency range to which the human ear is more sensitive. In some embodiments, the target frequency band may be 200Hz-5000Hz or a portion of the frequency range, as the human ear is more sensitive in the 200Hz-5000Hz frequency band. For example, the target frequency band may be 200Hz-800Hz in order for the acoustic output device 100 to have less leakage in the human ear to primarily hear the audio segment. For another example, the target frequency band may be the frequency band 2000Hz-4000Hz where the human ear is most sensitive. As another example, the target frequency band may also be 500Hz-4000Hz, 500Hz-3000Hz, 500Hz-2000Hz, 500Hz-1000Hz, 1000Hz-4000Hz, 1500Hz-3000Hz, 1500Hz-2000Hz, and so forth. In some embodiments, the target frequency band may include a continuous frequency range, or may be composed of a plurality of discrete frequency points. For example, the target frequency band may include target frequency points of 500Hz, 1000Hz, 2000Hz, 4000Hz, and the like, so that the sound of the acoustic output apparatus 100 at the frequency points can meet the purposes of near-field sound pressure approaching and far-field directivity (for example, heart directivity).
Because the frequency range of 200Hz-5000Hz is sensitive to human ears, far-field sound leakage can be effectively reduced in the frequency range by setting the target frequency band to the frequency range, so that the actual requirement is met.
The near-field sound pressure level difference refers to a difference in sound pressure level of sound radiated to the near-field position by each of the two or more sound sources formed by the acoustic output device 100. In this application, the near field location of a sound source may refer to a location within 5mm from the sound source (e.g., a first acoustic port or a second acoustic port). For ease of understanding, the near-field sound pressure level difference may be expressed as a difference in sound pressure level at the first acoustic port and the second acoustic port of the acoustic output device 100.
In some embodiments, the near-field sound pressure level may be measured by measuring the sound pressures of the sound (the first sound and the second sound) emitted from the first acoustic port and the second acoustic port Kong Fu, respectively, at a specific frequency point (for example, 1000 Hz), and calculating (for example, taking the ratio of the sound pressure to be measured to the reference sound pressure as a common logarithm, and multiplying by 20 to obtain the sound pressure level) to obtain the difference between the sound pressure levels of the first sound and the second sound. In some embodiments, when testing the sound of the first acoustic port (or the second acoustic port), a baffle may be used to separate the first acoustic port from the second acoustic port to avoid interference with the test by the second acoustic port (or the first acoustic port). The sound pressure at the first acoustic port may be understood as the sound pressure at a location proximate to the first acoustic port, and the sound pressure at the second acoustic port may be understood as the sound pressure at a location proximate to the second acoustic port. For example, the sound collection device may be disposed 4mm from the first acoustic hole (or the second acoustic hole) to collect the first sound (or the second sound) as the sound pressure at the first acoustic hole (or the second acoustic hole).
In some embodiments, when testing the sound of the first and second acoustic holes, the locations 4cm from the first and second acoustic holes (i.e., the acquisition locations) may be in a pair of opposite directions of the acoustic output device 100, respectively (e.g., the location 4cm from the first acoustic hole is in the direction that the second acoustic hole points toward the first acoustic hole, and the location 4cm from the second acoustic hole is in the direction that the first acoustic hole points toward the second acoustic hole). The sound collecting devices are respectively arranged at two collecting positions to collect the sound pressure levels of the acoustic output device 100, and the difference value of the two sound pressure levels is calculated, namely the near-field sound pressure level difference of the first acoustic hole and the second acoustic hole.
For a detailed description of acoustic centers, reference may be made to fig. 3A-3C and their associated descriptions.
In some embodiments of the present disclosure, by controlling the near-field sound pressure levels of the sounds radiated at the first acoustic port and the second acoustic port to be similar, it may be ensured that the first sound and the second sound effectively interfere with each other in a specific direction of the far field, thereby effectively reducing the leakage of sound from the acoustic output device 100 in the far field.
Illustratively, fig. 2B is a graph of near-field sound pressure levels of a first acoustic port and a second acoustic port as a function of frequency, according to some embodiments of the present description. As shown in fig. 2B, the near-field sound pressure level variation trend of the first acoustic port and the second acoustic port of the acoustic output device 100 in the frequency range of 200Hz-20kHz is substantially consistent, and the difference is less than 5dB, so as to effectively reduce the leakage sound of the far field of the acoustic output device 100 in the frequency range of 200Hz-20 kHz.
The near field sound pressure level difference may be adjusted in a number of ways. In some embodiments, the near-field sound pressure level difference may be adjusted by adjusting the ratio of the open areas of the first acoustic port and the second acoustic port.
The open area ratio refers to the area S of the first acoustic holes 1 Area S with second acoustic aperture 2 Ratio of (2), i.e. open area ratio is equal to S 1 /S 2 . It will be appreciated that when the number of first acoustic holes (or second acoustic holes) is two or more, the open area ratio may refer to the first soundTotal area of learning holes (S 1 ＝S 11 +S 12 +S 13 …+S 1n ) Total area with second acoustic aperture (S 2 ＝S 21 +S 22 +S 23 …+S 2m ) Is a ratio of (2). Wherein n and m are integers greater than 1.
In some embodiments, the ratio of the open area of the first acoustic port to the second acoustic port (i.e., the open area ratio) may be 0.2, 0.5, 1, 1.5, 2, 2.5, etc. In some embodiments, the ratio of the open area of the first acoustic port to the second acoustic port may range from 0.5 to 2. By controlling the range of the opening area ratio of the first acoustic hole to the second acoustic hole, the opening areas of the first acoustic hole and the second acoustic hole are close, and the acoustic resistance of the first acoustic hole and the acoustic resistance of the second acoustic hole are close, so that the near-field sound pressure level difference of the first acoustic hole and the second acoustic hole is reduced, the far-field sound leakage is more obvious, and the effect of reducing the far-field sound leakage is improved.
Further, the ratio of the opening areas of the first acoustic port to the second acoustic port may range from 0.8 to 1.25,0.9 to 1.1, or from 0.95 to 1.1. By further reducing the ratio range of the opening areas of the first acoustic holes and the second acoustic holes, the sound pressure level difference of the near field is reduced, and the effect of reducing far-field leakage can be further improved.
In some embodiments, the near-field sound pressure level difference may also be adjusted by adjusting the difference in acoustic loads of the first acoustic port and the second acoustic port.
The acoustic load refers to the sound pressure value P after passing through the first acoustic port (or the second acoustic port) 1 And the sound pressure value P not passing through the first acoustic hole (or the second acoustic hole) 0 Is equal to P 1 /P 0 . The larger the acoustic load (or, the closer to 1) is to the acoustic load of a certain acoustic port, the smaller the acoustic resistance is.
In some embodiments, the acoustic load may be based on the sound pressure value (corresponding to P) when the first acoustic port (or second acoustic port) is respectively measured at a particular distance to cover the gauze 1 ) And the sound pressure value when the gauze is not covered (corresponding to P 0 ) By calculating P 1 And P 0 And determines the acoustic load of the first acoustic port (or the second acoustic port). Specifically, when testing the sound of the first acoustic port (or the second acoustic port), the sound collecting device may be disposed at a distance of 4-5mm from the first acoustic port (or the second acoustic port), and then collect the sound pressure value (equivalent to P) when the first acoustic port (or the second acoustic port) covers the gauze 1 ) And the sound pressure value when the gauze is not covered (corresponding to P 0 ) Finally, the acoustic load of the first acoustic port (or the second acoustic port) is calculated. It should be noted that the test signal of the acoustic load may be a single frequency signal, wherein one or more frequency points may be selected, including but not limited to 100Hz, 200Hz, 300Hz, 500Hz, 1000Hz, 2000Hz, 5000Hz, and the resonant frequency f of the acoustic output device 100 0 Dots, etc.; the test signal can also select white noise, pink noise and sweep frequency signals. It should be noted that in some embodiments, the measured sound pressure level needs to be converted to a sound pressure value and then calculated to obtain the sound load. Alternatively, the sound pressure level measured before and after the first acoustic hole (or the second acoustic hole) covers the gauze may be differenced, and then the sound load value of the first acoustic hole (or the second acoustic hole) may be reversely calculated by a logarithmic formula.
In some embodiments, the difference in acoustic loads of the first acoustic port and the second acoustic port may include 0.1, 0.15, 0.2, etc. In some embodiments, the difference in acoustic load of the first acoustic port and the second acoustic port may be less than 0.15. It can be appreciated that the smaller the difference between the acoustic loads of the first acoustic port and the second acoustic port, the closer the acoustic resistances of the first acoustic port and the second acoustic port are, so that the smaller the near-field sound pressure level difference between the first acoustic port and the second acoustic port is, the more remarkable the effect of reducing far-field leakage.
Further, the difference in acoustic load of the first acoustic port and the second acoustic port may be less than 0.1. By further narrowing the range of the difference between the acoustic loads of the first acoustic port and the second acoustic port, the near-field sound pressure level difference between the first acoustic port and the second acoustic port can be further reduced, thereby further improving the effect of reducing far-field leakage.
In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 200Hz-5000Hz small, the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.05. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 500Hz-4000Hz small, the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.07. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 1000Hz-3000Hz small, the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.1. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 1500Hz-2500Hz small, the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.12.
In some embodiments, the near-field sound pressure level difference may also be adjusted by adjusting a ratio of the surface acoustic loads of the first acoustic port to the second acoustic port.
The surface acoustic load refers to the sound pressure value P after passing through the first acoustic port (or the second acoustic port) 1 And the sound pressure value P not passing through the first acoustic hole (or the second acoustic hole) 0 The ratio of (2) to the area S of the first acoustic port (or the second acoustic port), i.e. the surface acoustic load is equal to S P 1 /P 0 。
In some embodiments, the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may be 0.5, 1, 2.5, etc. In some embodiments, the ratio of the surface acoustic load of the first acoustic port to the second acoustic port may range from 0.5 to 3.5. The ratio of the surface acoustic loads of the first acoustic hole to the second acoustic hole is adjusted to be kept within a proper ratio range, so that the acoustic resistances of the first acoustic hole and the second acoustic hole are closer to each other, the near-field sound pressure level difference of the first acoustic hole and the second acoustic hole is reduced, and the effect of reducing far-field leakage is improved.
Further, the ratio of the surface acoustic load of the first acoustic port to the second acoustic port may range from 0.8 to 2. It can be appreciated that the effect of reducing far-field leakage can be made more pronounced by further narrowing the ratio range of the surface acoustic loads of the first acoustic port to the second acoustic port.
In some embodiments, to make the far field leakage of the acoustic output device 100 in the range of 200Hz-5000Hz small, the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may be in the range of 0.9-1.2. In some embodiments, to make the far field leakage of the acoustic output device 100 in the range of 500Hz-4000Hz small, the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may be in the range of 0.8-1.5. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 1000Hz-3000Hz small, the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may be in the range of 0.7-2. In some embodiments, to make the far field leakage of the acoustic output device 100 in the range of 1500Hz-2500Hz small, the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may be in the range of 0.6-2.7. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 1500Hz-2000Hz small, the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may be in the range of 0.5-3.5.
The far-field sound pressure level difference refers to a difference in sound pressure level of sound radiated in the far field by the first acoustic port and the second acoustic port, respectively. In this application, the far field of the first acoustic port (or second acoustic port) may refer to a location that is outside 10cm from the first acoustic port (or second acoustic port). For ease of understanding, the far-field sound pressure level difference for the first acoustic port and the second acoustic port may be expressed as the difference in sound pressure level at a greater distance (or symmetrical location) from the same or substantially the same, respectively, direction of the first acoustic port and the second acoustic port connection.
It should be noted that, the testing method of the far-field sound pressure level difference is similar to the testing method of the near-field sound pressure level difference, and the same points are not repeated. In contrast, when measuring the far-field sound pressure level, for example, when collecting the sound of the first acoustic port (or the second acoustic port), the sound collecting device may be disposed at a distance of 30cm from the first acoustic port (or the second acoustic port) for collection.
In some embodiments, the at least one pair of opposing directions may include two opposing directions in a direction of a line connecting the first acoustic port and the second acoustic port. For example, when the acoustic output device 100 is worn by a user, the direction toward the ear canal opening R1 and the direction away from the ear canal opening R1 are a pair of opposite directions.
In some embodiments, at least one pair of opposite directions may also include two directions that meet a predetermined range of angles relative to a point in position. For example, two points in the far field, which are respectively close to the first acoustic hole and the second acoustic hole, are connected with the connecting line of the connecting points of the first acoustic hole and the second acoustic hole, and the two directions are formed by connecting lines of the two points and the connecting points of the first acoustic hole and the second acoustic hole, and the two directions meet the preset included angle range. The preset included angle range can include, but is not limited to, 150 ° -180 ° and the like. Therefore, various situations possibly occurring in the practical application process can be comprehensively considered, and the effect of eliminating far-field leakage sounds can be ensured. For example, in a practical product, a strong directional radiation sound field, for example, a heart-shaped directional radiation sound field may be inclined or distorted, and in this case, due to the inclination or distortion of the heart-shaped directional radiation sound field, leakage sound of the acoustic output device 100 in multiple directions may be strong, thereby affecting performance of the acoustic output device 100. At this time, a relative set of directions may be given for possible tilt or distortion to make the strongly directive radiation sound field a more standard strongly directive radiation sound field. For example, when the strongly directive radiation sound field is tilted or distorted, one direction of the at least one pair of opposite directions may still be the direction of the connection line of the first acoustic hole and the second acoustic hole, and the other direction forms an angle of 10 ° with the opposite direction of the connection line of the first acoustic hole and the second acoustic hole; alternatively, each of the at least one pair of opposite directions may be at an angle (e.g., 5 °, 10 °, 15 °, 20 °) to the first acoustic port and second acoustic port connection direction, etc.
In some embodiments, to make the far-field leakage of the acoustic output device 100 in the 200Hz-5000Hz range small, the near-field sound pressure level difference may be less than 6dB, and the far-field sound pressure level difference may be not less than 12dB. In some embodiments, to make the far field leakage of the acoustic output device 100 in the range of 500Hz-4000Hz small, the near field sound pressure level difference may be less than 5dB and the far field sound pressure level difference may be not less than 10dB. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 1000Hz-3000Hz small, the near-field sound pressure level difference may be less than 4dB, and the far-field sound pressure level difference may be not less than 8dB. In some embodiments, to make the far field leakage of the acoustic output device 100 in the 1500Hz-2500Hz range small, the near field sound pressure level difference may be less than 3dB and the far field sound pressure level difference may be not less than 4dB. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the 1500Hz-2000Hz range small, the near-field sound pressure level difference may be less than 2dB, and the far-field sound pressure level difference may be not less than 3dB.
In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 200Hz-5000Hz small, the far-field sound pressure level difference is not less than 12dB, where the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.03. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 500Hz-4000Hz small, the far-field sound pressure level difference is not less than 10dB, where the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.05. In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 1000Hz-3000Hz, the far-field sound pressure level difference is not less than 6dB, where the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.1. In some embodiments, to make the far-field leakage of the acoustic output device 100 in the range of 1500Hz-2500Hz small, the far-field sound pressure level difference is not less than 4dB, where the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.12. In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 1500Hz-2000Hz, the far-field sound pressure level difference is not less than 3dB, where the difference in acoustic loading of the first acoustic port and the second acoustic port may be 0-0.15.
In some embodiments, to provide a small far-field leakage of the acoustic output device 100 in the 200Hz-5000Hz range, the far-field sound pressure level difference is not less than 12dB, where the ratio of the open areas of the first and second acoustic holes may be 0.75-1.1. In some embodiments, to provide a small far-field leakage of the acoustic output device 100 in the range of 500Hz-4000Hz, the far-field sound pressure level difference is not less than 10dB, where the ratio of the open areas of the first acoustic port and the second acoustic port may be 0.7-1.2. In some embodiments, to provide a small far-field leakage of the acoustic output device 100 in the range of 1000Hz-3000Hz, the far-field sound pressure level difference is not less than 6dB, where the ratio of the open areas of the first acoustic port and the second acoustic port may be 0.6-1.5. In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 1500Hz-2500Hz, the far-field sound pressure level difference is not less than 4dB, where the ratio of the open areas of the first acoustic port and the second acoustic port may be 0.6-1.7. In some embodiments, to provide a small far-field leakage of the acoustic output device 100 in the 1500Hz-2000Hz range, the far-field sound pressure level difference is not less than 3dB, where the ratio of the open areas of the first acoustic port and the second acoustic port may be 0.5-1.9.
In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 200Hz-5000Hz, the far-field sound pressure level difference is not less than 12dB, where the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may range from 0.9 to 1.2. In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 500Hz-4000Hz, the far-field sound pressure level difference is not less than 10dB, where the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may range from 0.8-1.5. In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 1000Hz-3000Hz, the far-field sound pressure level difference is not less than 6dB, where the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may range from 0.7-2. In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 1500Hz-2500Hz, the far-field sound pressure level difference is not less than 4dB, where the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may range from 0.6-2.7. In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 1500Hz-2000Hz, the far-field sound pressure level difference is not less than 3dB, where the ratio of the surface acoustic loads of the first acoustic port to the second acoustic port may range from 0.5 to 3.5.
FIG. 3A is a schematic diagram of a directional radiated sound field of an exemplary acoustic output device according to some embodiments of the present description; FIG. 3B is a schematic diagram of a directional radiated sound field of an exemplary acoustic output device according to other embodiments of the present disclosure; fig. 3C is a schematic diagram of a method of calculating distance between acoustic centers according to some embodiments of the present disclosure.
AS shown in fig. 3A-3B, AS 1 And AS (application server) 2 Respectively representing a first sound source AS and a second sound source formed by the sound emitting part 120 of the acoustic output device 100, the first sound source AS 1 First and second sound source AS 2 When the generated second sound source AS has a specific phase difference (120-179 DEG, for example) 1 And a second sound source AS 2 A strong directional radiation sound field, for example, a heart-type directional radiation sound field (as shown in fig. 3A), or an ultrasonic heart-type directional radiation sound field (as shown in fig. 3B) may be formed. The first acoustic port may constitute a first acoustic source AS 1 A first sound source AS 1 Can be considered to be located in the acoustic center of the first acoustic aperture, and the second acoustic aperture can constitute the second acoustic source AS 2 Second sound source AS 2 Can be considered to be located at the acoustic center of the second acoustic port.
The acoustic center of an acoustic port (e.g., a first acoustic port or a second acoustic port) refers to the equivalent sound emitting location of the acoustic port, which may be determined based on the shape, size, and number of acoustic ports. When the number of acoustic holes is one, the acoustic center may be a geometric center of the acoustic hole (e.g., the acoustic hole has an outer opening and an inner opening in a depth direction, the geometric center of the acoustic hole refers to a centroid of the outer opening). When the number of acoustic holes is two, the acoustic center may be the midpoint of the line connecting the geometric centers of the two acoustic holes. When the number of the acoustic holes is three, the acoustic center may be the center of a circumcircle of the geometric centers of the three acoustic holes, or the acoustic center may be the centroid of a triangle surrounded by the geometric center lines of the three acoustic holes. When the number of acoustic holes is four (or more), the acoustic center may be the centroid of a quadrangle (or polygon) surrounded by the geometric center lines of the four (or more) acoustic holes.
The spacing between the first acoustic port and the second acoustic port refers to the spacing of the acoustic center of the first acoustic port from the acoustic center of the second acoustic port. Taking the example that the number of the first acoustic holes is one and the number of the second acoustic holes is two as an illustration, one first acoustic hole and two second acoustic holes may be constructedThe triangle with three definite sides can be obtained by measurement, and the distance from the acoustic center of the first acoustic hole to the acoustic center of the second acoustic hole (when the number of the second acoustic holes is two, the acoustic center can be the midpoint of the connecting line of the geometric centers of the two acoustic holes), namely the first sound source AS 1 And a second sound source AS 2 Is a pitch of (c).
As shown in fig. 3C, the geometric center a of the first acoustic port, the geometric center B1 of the second acoustic port, and the geometric center B2 of the second acoustic port may form a triangle 300, and the side lengths of three sides of the triangle 300 may be measured as a, B, and C, respectively. The acoustic center of the first acoustic hole is the geometric center a of the first acoustic hole, and the equivalent acoustic centers of the two second acoustic holes are the midpoints B3 of the connecting lines of the geometric centers (i.e., the geometric centers B1 and B2) of the two second acoustic holes. The distance from the acoustic center of the first acoustic port to the equivalent acoustic center of the second acoustic port is the length of the line segment AB3 (denoted as x), and the value of x can be calculated according to the following formula:
cosβ＝-cos(180°-β) (1)
Wherein, β represents the angle formed by the line segment AB3 and the line segment B1B 3.
From equation (1) -equation (3) can be derived:
as shown in fig. 3A and 3B, it can be seen from the figures that the heart-shaped (fig. 3A) or ultrasonic-shaped (fig. 3B) directional radiation sound field has only one main lobe, the main lobe and the vicinity thereof radiate stronger, and the other directions radiate weaker (the sound field intensity in the opposite direction of the main lobe is also relatively weaker). When the user wears the acoustic output device 100, the main lobe can be directed to the ear canal opening R1 of the listener, and only radiation directed to the ear canal opening R1 and the vicinity thereof is strong, and other directions are all weak directivity directions, so that leakage sound of the acoustic output device 100 can be reduced. It will be appreciated that the first sound and the second sound in fig. 3A and 3B differ in phase difference (but are all within a specific range), and thus the radiated sound fields presented in fig. 3A and 3B also differ. The principle of forming a strong directional radiation sound field (for example, a heart-type or an ultrasonic-type directional radiation sound field) with a specific phase difference between a first sound and a second sound will be described below.
Fig. 4 is an exemplary dual source radiation schematic diagram shown in accordance with some embodiments of the present description.
AS shown in fig. 4, a first sound source AS 1 And a second sound source AS 2 Can represent two equivalent sound sources formed by the first acoustic aperture and the second acoustic aperture of the sound emitting portion 120 of the acoustic output device 100, respectively, P is a point in the far field, and l represents the first sound source AS 1 And a second sound source AS 2 Spacing, r 1 Representing a first sound source AS 1 Distance to point P, r 2 Representing a second sound source AS 2 Distance to point P, r represents the first sound source AS 1 And a second sound source AS 2 The distance from the midpoint O to the point P of the connecting line, θ represents the first sound source AS 1 And a second sound source AS 2 An included angle is formed between the connecting line of the (C) and the connecting line of the midpoint O and the point P.
First sound source AS 1 And a second sound source AS 2 The sound pressures at the positions can be respectively:
wherein A represents the intensity of the point sound source, ω represents the angular frequency, j represents the imaginary part, t represents the time,representing a first sound source AS 1 And a second sound source AS 2 Phase difference, k tableOscillometric vectors. In far field conditions (r>>l，kl<<1) Distance r 1 、r 2 Can be expressed as: />
Therefore, the sound pressure amplitude |p| of the far-field point P can be expressed AS the first sound source AS 1 And a second sound source AS 2 Superposition of sound fields:
when a heart-shaped directional radiation sound field is required, that is, θ=180°, there is a minimum value of the sound pressure amplitude |p| of the far-field point P. Derivative of |p| is:
Solving the above equation (7) can obtain the information about the first sound source AS 1 And a second sound source AS 2 Phase difference betweenThe relation to be satisfied:
from equation (8), it can be seen that the first sound source AS is 1 And a second sound source AS 2 Can form heart-shaped directional radiation sound field, and phase difference between two sound sourcesA certain relation with kl needs to be satisfied. Since the wave vector k is related to the frequency f, the phase difference between two sound sources is +.>As well as frequency.
FIG. 5 is a first sound source AS corresponding to equation (8) 1 And a second sound source AS 2 Phase difference betweenSchematic diagram of the relationship between the frequency f and the spacing l.
As shown in fig. 5, the horizontal axis represents frequency f in Hz; the vertical axis represents the spacing l, in mm, between two sound sources, and the respective curves represent the phase difference required under different conditions (i.e. different frequencies f and different spacings l)AS can be seen from comparing the curves in fig. 5, when the distance l is the same, the first sound source AS is within the preset frequency range 1 And a second sound source AS 2 The phase difference between them is inversely related to the magnitude of the frequency. For example, in the range of 200Hz-2000Hz, the higher the frequency, the desired first sound source AS 1 And a second sound source AS 2 The smaller the phase difference between them; the lower the frequency, the required first sound source AS 1 And a second sound source AS 2 The greater the phase difference therebetween. Similarly, when the frequencies are the same, the first sound source AS 1 And a second sound source AS 2 The phase difference between them is inversely related to the magnitude of the separation between the two sound sources. The larger the spacing, the more first sound source AS is required 1 And a second sound source AS 2 The smaller the phase difference between them; the smaller the spacing, the required first sound source AS 1 And a second sound source AS 2 The greater the phase difference therebetween. It is to be appreciated that in actual measurement, when the phase difference is inversely related to the magnitude of a plurality of consecutive frequencies within a certain frequency range and/or a plurality of consecutive pitches within a certain range of dual sound source pitches, the phase difference can be considered as inversely related to the magnitude of the frequency and/or the pitch between two sound sources. By way of example only, a plurality of (e.g., 5, 10, etc.) frequencies and their corresponding phase differences may be measured at equal step frequencies (e.g., every 1Hz, 10Hz, 50Hz, 100Hz, 200Hz, etc.), where the plurality of frequencies and their corresponding phase differences satisfy a negative correlation relationshipThe phase difference is considered to be inversely related to the magnitude of the frequency.
In practice, the pitch l is usually fixed, the phase differenceThe correspondence with kl can be reduced to a correspondence of frequency and phase difference. That is, when the first sound source AS is provided that the distance l is constant 1 And a second sound source AS 2 When the phase difference and the frequency meet a certain corresponding relation, a first sound source AS 1 And a second sound source AS 2 A radiation sound field with heart directivity can be formed. For example only, the following table shows a spacing l of 3mm, in order to make the first sound source AS 1 And a second sound source AS 2 Can form heart-shaped directional radiation sound field, and the required phase difference is +.>The correspondence table of (and can be understood as being the optimum phase difference that can achieve the heart-shaped directional radiation sound field) and the frequency f may be:
it can be seen from the table that at different frequencies, the first sound source AS is intended 1 And a second sound source AS 2 Forming a heart-shaped directional radiation sound field, a first sound source AS 1 And a second sound source AS 2 Phase difference required betweenIs different. It can also be seen from the table that even the phase differences corresponding to the different frequencies are +.>Different, but not so different. For example, 200Hz shown in the table corresponds to a phase difference of 179 °,2000Hz corresponds to a phase difference of 173 °, and the two phase differences differ only by 6 °. Thus, when a fixed phase difference is determined +.>(e.g., 176 °) or a phase difference range (e.g., 120 ° -179 °), a heart-like directional radiation sound field, such as the ultra-heart directional radiation sound field shown in fig. 3B, can be formed in a wide frequency range (e.g., 200Hz-2000 Hz) even if a heart-like directional radiation sound field (shown in fig. 3A) cannot be formed at some frequencies.
Fig. 6 is a schematic diagram of a directional radiated sound field at different frequencies according to some embodiments of the present description. It should be noted that fig. 6 corresponds to a pitch l=3 mm, and a phase differenceAnd when the sound field is radiated under the far field condition of 0.5m from the sound source, the sound field corresponding to different frequencies is radiated. As shown in fig. 6, curves 610, 620, 630, 640 are directional radiation sound field curves corresponding to frequencies of 200Hz, 500Hz, 1000Hz, 2000Hz, respectively, under far field conditions. As can be seen from fig. 6, the radiation sound field of curve 630 has a main lobe (the sound field intensity is the largest) with the smallest sound field intensity in the opposite direction (the 180 direction), therefore, the sound field radiation directivity (heart-type directivity) of the curve 630 is optimal with respect to the other three curves (i.e., phase differenceThe directional radiation sound field at a frequency of 1000Hz is optimal). The sound field intensity in the opposite direction of the main lobe of the radiated sound field corresponding to the curves 610, 620, 640 is larger than that of the curve 630, which forms a heart-like directivity. From this, it can be seen that the phase difference +.>In the frequency range of 200 Hz-2000 Hz, the two sound sources can form a strong directive radiation sound field. At the same time, as can be seen from the above description (the difference of the optimal phase differences corresponding to different frequencies is not large), the phase difference is within a certain range, for example, 120-179 degrees, and the frequency range is 200-2000 Hz, and both sound sources can also be used Forming a strongly directive radiation sound field.
The leakage reduction effect of the acoustic output device 100 in the far field may be affected by the rate of change of the near-field phase difference of the sound radiated from the sound source. The rate of change of the phase difference may refer to the rate of change of the phase difference with frequency of the sound emitted from the first acoustic Kong Fu and the sound emitted from the second acoustic Kong Fu. In some embodiments, the rate of change of the phase difference may be represented based on the phase difference and octave. Wherein octave (oct) refers to the interval between two frequencies with a ratio of 2 or 1/2 on the frequency response curve. For example, 1000Hz-2000Hz is an octave, 2000Hz-4000Hz is an octave; for another example, 1500Hz-3000Hz is an octave, 3000Hz-6000Hz is an octave, etc.
When the change rate of the control near-field phase difference shows a tendency to slowly change, it is possible to avoid distortion of the sound radiated by the far field of the acoustic output device, thereby enabling the two sound sources to tend to form a strongly directive radiation sound field (for example, a heart-shaped or super-heart-shaped directive radiation sound field) in a wider frequency range. In some embodiments, the rate of change of the phase difference of the sound emitted from the first acoustic Kong Fu and the sound emitted from the second acoustic Kong Fu may be less than 30 °/oct over a frequency range of 1000Hz-8000 Hz.
In some embodiments, the rate of change of the near field phase difference may be less than 20 °/oct over a frequency range of 1000Hz-8000 Hz. By further controlling the rate of change of the near-field phase difference, two sound sources can be further formed into a more standard strong directional radiation sound field (for example, a heart-type or super-heart-type directional radiation sound field), and leakage sound in the opposite direction of the ear canal direction and leakage sound in other directions are smaller, so that the opening of the ear canal and the privacy of listening can be better considered.
Further, in some embodiments, the rate of change of the near-field phase difference may be less than 25 °/oct in order for the acoustic output device 100 to form a relatively standard intense directional radiated sound field in the range of 1000Hz-5000 Hz. In some embodiments, the rate of change of the near-field phase difference may be less than 20 °/oct in order for the acoustic output device 100 to form a relatively standard intense directional radiated sound field in the 3000Hz-4000Hz range. In some embodiments, the rate of change of the near-field phase difference may be less than 15 °/oct in order for the acoustic output device 100 to form a relatively standard intense directional radiated sound field in the 2000Hz-3000Hz range. In some embodiments, the rate of change of the near-field phase difference may be less than 10 °/oct in order for the acoustic output device 100 to form a relatively standard intense directional radiated sound field in the 1000Hz-2000Hz range.
In some embodiments, the absolute value of the difference between the phase difference at 1000Hz and the phase difference at 2000Hz of the sound emitted from the first acoustic Kong Fu and the sound emitted from the second acoustic Kong Fu may be less than 30 °. For example, the phase difference between the sound emitted from the first acoustic Kong Fu and the sound emitted from the second acoustic Kong Fu at 1000Hz is 159 ° -178 °, the phase difference between the sound emitted from the first acoustic Kong Fu and the sound emitted from the second acoustic Kong Fu at 2000Hz is 149 ° -176 °, and the absolute value of the difference between the phase difference between the sound emitted from the first acoustic Kong Fu and the sound emitted from the second acoustic Kong Fu at 1000Hz and the phase difference at 2000Hz is between 2 ° -29 °, which is less than 30 °. Because the frequency range of 1000Hz-2000Hz is in the frequency range where the human ear is more sensitive, based on this, by controlling the absolute value of the difference between the phase difference at 1000Hz between the sound emitted from the first acoustic Kong Fu and the sound emitted from the second acoustic Kong Fu and the phase difference at 2000Hz within 30 °, the effect of reducing far-field leakage sound can be further improved on the premise of forming a more standard strong directional sound field.
In some embodiments, to make the far-field leakage of the acoustic output device 100 in the 200Hz-5000Hz range small, the far-field sound pressure level difference is not less than 12dB, at which time the near-field phase difference rate of change is less than 29 °/oct. In some embodiments, to make the far field leakage of the acoustic output device 100 in the range of 500Hz-4000Hz small, the far field sound pressure level difference is not less than 10dB, at which time the near field phase difference rate of change is less than 25 °/oct. In some embodiments, to make the far-field leakage of the acoustic output device 100 small in the range of 1000Hz-3000Hz, the far-field sound pressure level difference is not less than 6dB, at which time the near-field phase difference rate of change is less than 20 °/oct. In some embodiments, to make the far field leakage of the acoustic output device 100 in the 1500Hz-2500Hz range small, the far field sound pressure level difference is not less than 4dB, at which time the near field phase difference rate of change is less than 15 °/oct. In some embodiments, to make the far field leakage of the acoustic output device 100 small in the 1500Hz-2000Hz range, the far field sound pressure level difference is not less than 3dB, at which time the near field phase difference rate of change is less than 10 °/oct.
FIG. 7A is a schematic diagram of an exemplary sounding portion shown according to some embodiments of the present disclosure; FIG. 7B is a schematic diagram of an exemplary sounding portion according to further embodiments of the present disclosure; fig. 7C is a schematic diagram of an exemplary sounding portion according to further embodiments of the present disclosure.
As shown in fig. 7A, the sound emitting part 700 may include a first cavity 722 and a second cavity 723 to which at least one acoustic driver 721 is acoustically coupled. In some embodiments, the at least one acoustic driver 721 may include a diaphragm, and the at least one acoustic driver 721 has front and rear sides distinguished by the diaphragm and radiates sound to the first and second cavities 722 and 723 through the front and rear sides, respectively. In some embodiments, the at least one acoustic driver 721 may also include two acoustic drivers (i.e., the acoustic driver 721 of fig. 7A may be replaced with two parallel acoustic drivers) that are driven by two sets of electrical signals to radiate sound to the first and second cavities 722, 723, respectively. The sound in the first cavity 722 may radiate to the outside through the first acoustic port 724, i.e., the first acoustic port 724 radiates the first sound V to the outside 1 The method comprises the steps of carrying out a first treatment on the surface of the The sound in the second cavity 723 may radiate to the outside through the second acoustic port 725, i.e., the second acoustic port 725 radiates the second sound V to the outside 2 。
In some embodiments, in order to enable the sound radiating to the far field of the sound generating section 700 within the target frequency band (e.g., 200Hz to 5000 Hz) to exhibit strong directivity (e.g., heart-shaped or super-heart-shaped), it is necessary to cause the first sound V radiated from the first acoustic hole 724 to be 1 And a second sound V radiated from the second sound hole 725 2 Is within a specific range (e.g., 120 ° -179 °). Since the acoustic drivers 721 are directed to the first chambers respectivelyThe initial value of the phase difference of the two acoustic waves radiated from the body 722 and the second cavity 723 is 180 deg., and therefore, the acoustic structures in the first cavity 722 and/or the second cavity 723 may be arranged such that the first sound V 1 And a second sound V 2 The phase difference of (2) satisfies the condition. In some embodiments, the sound emitting portion 700 may include an acoustic structure 726 disposed within the first cavity 722 and/or the second cavity 723. Acoustic structure 726 may be for regulating the first sound V 1 And/or a second sound V 2 To adjust the actual output phase of the first sound V 1 With a second sound V 2 Is a phase difference of (a) and (b). In some embodiments, the acoustic structure 726 may cause the first sound V to 1 First acoustic path and second acoustic V propagating in first cavity 722 2 Having a difference in sound path between the second sound paths propagating in the second cavity 723, thereby changing the first sound V radiated from the first acoustic hole 724 1 And from the second acoustic port 725 radiated second sound V 2 Phase difference between them. In this embodiment, the acoustic structure 726 is illustrated as being disposed in the second cavity 723, but it is understood that in other alternative embodiments, the acoustic structure 726 may be disposed in the first cavity 722 or different acoustic structures may be disposed in the first and second cavities 722 and 723.
In some embodiments, the acoustic structure 726 may include a baffle having one end connected to an inner wall of the second cavity 723 and the other end of the baffle being a free end. In some embodiments, as shown in fig. 7A, 4 baffles may be disposed in the second cavity 723, two baffles being disposed on a first inner wall 7231 of the second cavity 723, the remaining two baffles being disposed on a second inner wall 7232 (the second inner wall 7232 being disposed opposite the first inner wall 7231), and free ends of the baffles on the two inner walls being disposed opposite each other. At this time, there is a gap between the free ends of the two opposing baffles, and sound can bypass the baffles and pass from the gap to the second acoustic port 725. In some embodiments, other arrangements of the number and/or positions of baffles in the second cavity 723 are possible. For example, as shown in fig. 7B, a baffle may be provided on only one inner wall (e.g., the second inner wall 7232) of the second cavity 723, one end of the baffle being connected to the second inner wall 7232, a free end of the baffle extending to the vicinity of the first inner wall 7231 (a space is formed between the free end of the baffle and the first inner wall 7231), and sound being able to bypass the baffle and pass from the space between the free end of the baffle and the first inner wall 7231 to the second acoustic hole 725. For another example, as shown in fig. 7C, two ends of the baffle may be connected to the first inner wall 7231 and the second inner wall 7232, respectively, and at this time, the baffle may be perforated, and sound may bypass the baffle and be transmitted to the second acoustic port 725 through the perforation. The path that sound travels (i.e., the sound path) through the baffle as it passes around to the second acoustic port 725 is altered relative to if the baffle were not present. The sound wave radiated from the front side of the acoustic driver 721 is radiated from the first acoustic port 724 to the outside through the first cavity 722, the path travelled by the sound wave is a first sound path L1, the sound wave radiated from the rear side of the acoustic driver 721 is radiated from the second acoustic port 725 to the outside through the second cavity 723 and the acoustic structure 726, the path travelled by the sound wave is a second sound path L2, and a sound path difference exists between the first sound path L1 and the second sound path L2.
First sound V radiated from first acoustic hole 724 1 And a second sound V radiated from the second sound hole 725 2 The phase difference delay of (2) may be:
where c represents the speed of sound. Thus, the first sound V 1 And a second sound V 2 Is of the phase difference of (2)The method comprises the following steps:
it is thus understood that the first sound V can be controlled by controlling the first sound path L1 and the second sound path L2 sound path difference (for example, the sound path difference can be made to lie in the range of 1mm to 57 mm) 1 And a second sound V 2 Is set so that the first sound V 1 With a second sound V 2 The phase difference of (a) is located at 120 ° -179 °, thereby enabling the sound emitting portion 700 to exhibit strong directivity (e.g., heart-type or super-heart-type) of sound radiated toward the far field.
It will be appreciated that the number, location, size, and arrangement of baffles, etc. may affect the second sound path L2 that the sound waves travel in the second cavity 723 and thus the first sound V 1 With a second sound V 2 Thus, according to the first sound V 1 With a second sound V 2 The number, position, size, setting mode, etc. of the baffles are reasonably set.
Furthermore, in the present embodiment, it can be seen that the first sound V is in the case that other parameters (e.g., the first sound path, the second sound path) are the same 1 With a second sound V 2 Is inversely related to frequency. The higher the frequency is, the first sound V 1 With a second sound V 2 The smaller the phase difference of (2); the lower the frequency is, the first sound V 1 And second sound Sound V 2 The greater the phase difference of (c).
Fig. 8 is another exemplary sounding portion schematic diagram shown in accordance with some embodiments of the present disclosure.
As shown in fig. 8, an acoustic structure that changes the propagation speed of sound may be provided in the first cavity 822 and/or the second cavity 823 of the sound emitting portion 800. For example, the acoustic structure may be a slow acoustic structure capable of slowing down the speed of sound as it passes in itself. The sound speed of sound wave propagation in air is faster than the sound speed of sound wave propagation in a slow acoustic structure. In some embodiments, the slow acoustic structure may include at least one of an acoustic gauze, an acoustic porous material, and the like. When the sound wave passes through the micropores in the gauze or the porous material, the speed of the sound wave is slowed down when the sound wave passes through the micropores due to the viscous action of the micropores on the air, so that the slow action is achieved. Specifically, the sound velocity of sound wave propagating in air (also referred to as normal sound velocity) is c, the sound velocity of sound wave propagating in a slow acoustic structure (also referred to as equivalent sound velocity) is c ', and as is known from the above description, there is c' <c. Thus, by providing a slow acoustic structure in the cavity to alter the propagation velocity of soundDegree of the first sound V can be regulated and controlled 1 And/or a second sound V 2 To adjust the actual output phase of the first sound V 1 With a second sound V 2 Is a phase difference of (a) and (b).
In this embodiment, taking the example that the slow acoustic structure 826 is disposed in the second cavity 823 as shown in fig. 8, a slow acoustic structure 826 may be disposed in the second cavity 823, the sound wave radiated from the front side of the acoustic driver 821 radiates from the first acoustic hole 824 to the outside, the sound wave travels along a path that is a first sound path L1, the sound wave radiated from the rear side of the acoustic driver 821 radiates from the second acoustic hole 825 to the outside, and the sound wave may travel along a path that includes a second sound path L2 that propagates through the air and a third sound path L3 that propagates through the slow acoustic structure 826.
First sound V radiated from first acoustic hole 824 1 And a second sound V radiated from the second sound hole 825 2 The phase difference delay of (2) may be:
where c represents the normal sound velocity and c' represents the equivalent sound velocity in the slow acoustic structure 826. Thus, the first sound V 1 And a second sound V 2 Is of the phase difference of (2)The method comprises the following steps:
it can be appreciated that the first sound V can be controlled by controlling the equivalent sound velocity and/or the third sound path L3 of the sound wave propagating in the slow acoustic structure 826 (e.g., the ratio of the equivalent sound velocity to the normal sound velocity in the slow acoustic structure can be in the range of 0.02-0.5) 1 And a second sound V 2 Is set so that the first sound V 1 With a second sound V 2 The phase difference of the sound generating part is 120-179 degreesThe sound radiated to the far field 800 can exhibit strong directivity (e.g., heart-type or hypercardioid-type).
Further, in the present embodiment, it can also be seen that the first sound V is in the case where other parameters (e.g., equivalent sound velocity, first sound path, second sound path, third sound path) are the same 1 With a second sound V 2 Is inversely related to frequency. The higher the frequency is, the first sound V 1 With a second sound V 2 The smaller the phase difference of (2); the lower the frequency is, the first sound V 1 With a second sound V 2 The greater the phase difference of (c).
Fig. 9 is another exemplary sounding portion schematic diagram shown in accordance with some embodiments of the present disclosure.
As shown in fig. 9, an expanding acoustic structure 926 may be disposed within the first cavity 922 and/or the second cavity 923 of the sound emitting portion 900. Expanding the acoustic structure 926 may change (e.g., expand) the cross-sectional area of the first cavity 922 or the second cavity 923 at different locations along the sound transmission path. When the acoustic wave propagates in the waveguide (i.e., the air waveguide formed by the first cavity 922 or the second cavity 923), if the cross-sectional area of the waveguide at different positions on the propagation path of the acoustic wave changes, the acoustic wave is reflected at the position where the cross-sectional area changes, which means that the equivalent impedance of the medium changes. Accordingly, parameters related to the equivalent impedance (such as equivalent sound velocity, equivalent density, etc.) will also change accordingly, so that the phase of the sound wave will change. For example, the effect of the change in equivalent acoustic velocity of the expanded acoustic structure 926 is primarily related to the ratio of the cross-sectional area of the second cavity 923 after expansion of the expanded acoustic structure 926 to the original cross-sectional area of the second cavity 923. In some embodiments, the actual equivalent sound velocity may be obtained by means of simulation or experimental testing, or the like.
In the present embodiment, taking the example that the expanded acoustic structure 926 is disposed in the second cavity 923 as shown in fig. 9, the expanded acoustic structure 926 may be disposed on two opposite sidewalls of the second cavity 923, and the expanded acoustic structure 926 causes abrupt changes in the cross-sectional area of the second cavity 923 before and after a specific position on the sound transmission path. In some embodiments, expanding acoustic structure 926 may be expandingZhang Qiang a. The invention relates to a method for producing a fibre-reinforced plastic composite. The expansion chamber may have a rectangular configuration as shown in fig. 9, and in other embodiments the cross-sectional area of the expansion acoustic structure 926 may have other shapes, such as triangular, trapezoidal, etc. The structural shape of the expansion chamber can be based on the first sound V 1 With a second sound V 2 Is reasonably set.
As shown in fig. 9, the sound wave radiated from the front side of the acoustic driver 921 radiates from the first acoustic hole 924 to the outside, and the sound wave travels along the first acoustic path L1, and the sound wave radiated from the rear side of the acoustic driver 921 radiates from the second acoustic hole 925 to the outside through the expanded acoustic structure 926 and the second cavity 923, and travels along the second acoustic path L2. The sound velocity in the first sound path L1 is the normal sound velocity c, and the sound velocity in the second sound path L2 is the equivalent sound velocity c'. First sound V radiated from first acoustic hole 924 1 The phase difference delay from the second sound radiated from the second acoustic port 925 is:
where c represents the normal sound velocity and c' represents the equivalent sound velocity in the expanded acoustic structure 926. Thus, the first sound V 1 And a second sound V 2 Is of the phase difference of (2)The method comprises the following steps:
it can be seen that the first sound V can be controlled by providing a flared acoustic structure 926 in the cavity to control the equivalent speed of sound of the sound wave propagating in the cavity 1 And a second sound V 2 Is set so that the first sound V 1 With a second sound V 2 The phase difference of (a) is located at 120 ° to 179 °, thereby enabling the sound emitting portion 900 to exhibit strong directivity (e.g., heart-shaped or super-heart-shaped) of sound radiated to the far field.
Furthermore, in the present embodiment, it can also be seen that the first sound V, in the case where other parameters (e.g., first sound path, second sound path, equivalent sound velocity) are the same 1 With a second sound V 2 Is inversely related to frequency. The higher the frequency is, the first sound V 1 With a second sound V 2 Is of the phase difference of (2) the smaller; the lower the frequency is, first sound V 1 With a second sound V 2 The greater the phase difference of (c).
Fig. 10A is another exemplary sounding portion schematic diagram shown in accordance with some embodiments of the present disclosure.
The sound emitting part 1000 shown in fig. 10A has a structure similar to that of the sound emitting part 700 shown in fig. 7A, for example, the sound emitting part 1000 may include at least one acoustic driver 1021, a first cavity 1022, and a second cavity 1023. The first cavity 1022 may have at least one first acoustic aperture 1024 and the second cavity 1023 may have at least one second acoustic aperture 1025. For details of the acoustic driver 1021, the first cavity 1022, the second cavity 1023, the first acoustic aperture 1024, and the second acoustic aperture 1025, see the associated description of fig. 7A. The sounding part 1000 is different from the sounding part 700 in the acoustic structure. As shown in fig. 10A, a sound absorbing structure 1026 may be provided within the first cavity 1022 and/or the second cavity 1023 of the sound emitting portion 1000. In some embodiments, the sound absorbing structure 1026 may have a resonant frequency. Modulation of sound (e.g., phase modulation) near the resonant frequency of the sound absorbing structure 1026 may be utilized to control the actual output phase difference of the two sound waves. In some embodiments, the sound absorbing structure 1026 may be a helmholtz resonator. In some embodiments of the present invention, in some embodiments, the sound absorbing structure 1026 may be a microperforated panel resonator. In some embodiments, the sound absorbing structure 1026 may be a 1/4 wavelength tube resonator.
In this embodiment, the sound absorbing structure 1026 is disposed in the second cavity 1023, and the sound absorbing structure 1026 may be disposed on a side wall of the second cavity 1023 and be in acoustic communication with the second cavity 1023. Taking a Helmholtz resonant cavity as an example, the resonant frequency f 0 The method comprises the following steps:
where M represents the acoustic mass (mainly related to the orifice parameters of the Helmholtz resonator), C represents the sound volume (mainly related to the cavity parameters at the back end of the helmholtz resonator).
Fig. 10B is a schematic diagram of the frequency response of the helmholtz resonator.
Where the horizontal axis represents frequency in Hz and the vertical axis represents amplitude response (in dB) or phase response (in deg). The solid line is the amplitude response of the frequency response and the dashed line is the phase response of the frequency response. As shown in fig. 10B, when the resonance frequency f of the helmholtz resonator is 0 At=2000 Hz, the amplitude response appears as a formant at 2000Hz, while the phase response is around 2000Hz, with the phase gradually changing from 180 ° to eventually approach 0 ° as the frequency increases. It is understood that the phase difference varies from 179 ° to 150 ° in the low frequency range (e.g., between 40Hz and 1000 Hz), which substantially meets the phase difference requirements required to achieve the heart-type directivity or the super-heart-type directivity described in the embodiments of the present specification. Accordingly, the actual output phase difference of the first sound and the second sound can be controlled by providing the sound absorbing structure 1026 in the cavity to regulate the phase of the sound radiated from the corresponding acoustic hole of the cavity, so that the sound radiated to the far field by the sound emitting portion 900 can exhibit strong directivity (for example, heart type or super heart type).
In some embodiments, when at least one acoustic driver of the sound emitting portion is a single driver or includes two acoustic drivers, the first sound V may be adjusted in the manner described in FIGS. 7A-10A 1 With a second sound V 2 Is a phase difference of (a) and (b). In this manner, the acoustic driver radiates sound into the first and second chambers with a phase difference of 180 ° to change the first sound V by providing different types of acoustic structures (e.g., baffle, slow acoustic structure, expanded acoustic structure, sound absorption structure) in the chambers 1 Or a second sound V 2 Thereby realizing the first sound V 1 With a second sound V 2 Is of the phase difference of (a)And (5) adjusting. In some embodiments, when the at least one acoustic driver includes two acoustic drivers, the first sound V may also be adjusted by modulating the electrical drive signals corresponding to the two acoustic drivers 1 With a second sound V 2 Is a phase difference of (a) and (b). In some embodiments, the phases of the two electrical drive signals may be set, respectively, such that the phase of sound radiated by one acoustic driver to the first cavity is not exactly opposite to the phase of sound radiated by the other acoustic driver to the second cavity.
FIG. 11 is an exemplary block diagram of a sound emitting portion having two acoustic drivers according to some embodiments of the present description; fig. 12 is an exemplary block diagram of a sound emitting portion having two acoustic drivers according to other embodiments of the present description.
As shown in fig. 11, the sound emitting part 1100 may include a first acoustic driver 1121A, a second acoustic driver 1121B, a first cavity 1122, and a second cavity 1123. The first cavity 1122 may be provided with a first acoustic hole 1124, and the first acoustic driver 1121A may radiate the first sound V to the outside through the first cavity 1122 and the first acoustic hole 1124 1 The method comprises the steps of carrying out a first treatment on the surface of the The second cavity 1123 is provided with a second acoustic hole 1125, and the second acoustic driver 1121B can radiate the second sound V to the outside through the second cavity 1123 and the second acoustic hole 1125 2 . In some embodiments, the first acoustic driver 1121A and the second acoustic driver 1121B may be driven by two sets of electrical signals, and the first sound V may be caused by setting the phases of the two sets of electrical driving signals to be different 1 With a second sound V 2 The phase difference of (2) is between 120 deg. -179 deg.. For example, as shown in FIG. 11, the phase difference between the electrical driving signal driving the first acoustic driver 1121A and the electrical driving signal driving the second acoustic driver 1121B may be set to 120-179, in which case no other acoustic structures may be provided in the first and second chambers 1122 and 1123, and the sound propagation paths of the sound in the respective chambers may be substantially the same, thereby realizing the first sound V 1 With a second sound V 2 The phase difference of (2) is 120 DEG to 179 deg. For another example, as shown in FIG. 12, an electrical driving signal for driving the first acoustic driver 1121A may be providedThe phase difference between the driving electrical signals of the first and second acoustic drivers 1121B is not 120 ° -179 °, in which case the first sound V may be generated by providing an acoustic structure in the first and/or second chambers 1122, 1123 (e.g., a slow acoustic structure 1126 is provided in the second chamber 1123 as shown in fig. 12) 1 With a second sound V 2 The phase difference of (2) is 120 DEG to 179 deg.
The acoustic output device according to the embodiments of the present disclosure may have beneficial effects including, but not limited to: (1) The phase difference of two sounds generated by the sound generating part is regulated, so that the near-field sound pressure level difference of the first acoustic hole and the second acoustic hole is smaller, the far-field sound pressure level difference is larger, and the sound emitted by the acoustic output device to the far field in a target frequency band can show stronger directivity, so that the volume of the acoustic output device in the direction of the auditory canal opening is maximum when a listener wears the acoustic output device, and the leakage in the opposite direction of the auditory canal opening direction and the leakage in other directions are smaller, and further the openness of the auditory canal and the privacy of the auditory canal can be better considered; (2) The phase difference of two sounds generated by the sound generating part is regulated and controlled by arranging various acoustic structures (such as a baffle, a slow acoustic structure, an expanded acoustic structure and a sound absorbing structure) on the sound generating part of the acoustic output device, so that the regulation and control of the phase difference are more flexible and more accurate, and the practicability of the acoustic output device is improved; (3) When at least one acoustic driver in the sound generating part comprises two acoustic drivers, the two paths of electric driving signals are directly regulated to realize the regulation and control of the phase difference of the two paths of sound, so that the structure of the acoustic output device is simpler and the cost is lower.
While the basic concepts have been described above, it will be apparent to those skilled in the art that the foregoing detailed disclosure is by way of example only and is not intended to be limiting. Although not explicitly described herein, various modifications, improvements, and adaptations to the present disclosure may occur to one skilled in the art. Such modifications, improvements, and modifications are intended to be suggested within this specification, and therefore, such modifications, improvements, and modifications are intended to be included within the spirit and scope of the exemplary embodiments of the present invention.

Claims (13)

1. An acoustic output device comprising:
at least one acoustic driver;
a first cavity and a second cavity acoustically coupled to the at least one acoustic driver, the first cavity having a first acoustic port and the second cavity having a second acoustic port, the at least one acoustic driver radiates sound having a phase difference to the outside through the first acoustic port and the second acoustic port, wherein,
the near-field sound emitted from the first acoustic Kong Fu and the near-field sound emitted from the second acoustic Kong Fu have a near-field sound pressure level difference of less than 6dB in a target frequency band, and the acoustic output device exhibits directivity to sound of far-field radiation in the target frequency band as if the sound emitted from the first acoustic aperture and the second acoustic Kong Fu have a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions.
2. The acoustic output device of claim 1, wherein the target frequency band is 200Hz-5000Hz.
3. The acoustic output device of claim 1, wherein the near-field sound pressure level difference is less than 3dB and/or the far-field sound pressure level difference is not less than 6dB.
4. The acoustic output device according to claim 1, wherein the rate of change of the phase difference is less than 30 °/oct over a frequency range of 1kHz-8 kHz.
5. The acoustic output device of claim 4, wherein an absolute value of a difference between a phase difference at 1kHz and a phase difference at 2kHz of the near-field sound emitted from the first acoustic Kong Fu and the near-field sound emitted from the second acoustic Kong Fu is less than 30 °.
6. The acoustic output device of claim 1, wherein the target frequency band comprises target frequencies of 500Hz, 1kHz, 2kHz, and 4 kHz.
7. The acoustic output device of claim 1, wherein a ratio of an open area of the first acoustic port to the second acoustic port is in a range of 0.5-2.
8. The acoustic output device of claim 1, wherein the difference in acoustic load of the first acoustic port and the second acoustic port is less than 0.15.
9. The acoustic output device of claim 1, wherein a ratio of a surface acoustic load of the first acoustic port to the second acoustic port is in the range of 0.5-3.5.
10. An acoustic output device comprising:
at least one acoustic driver;
a first cavity and a second cavity acoustically coupled to the at least one acoustic driver, the first cavity having a first acoustic port formed therein, the second cavity having a second acoustic port formed therein, the at least one acoustic driver radiating sound having a phase difference to the outside through the first acoustic port and the second acoustic port, wherein,
within a target frequency band, the acoustic output device exhibits directivity to far-field radiated sound as represented by sound emitted from the first acoustic port and the second acoustic Kong Fu having a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions, an
The difference in acoustic load of the first acoustic port and the second acoustic port is less than 0.15.
11. An acoustic output device comprising:
at least one acoustic driver;
a first cavity and a second cavity acoustically coupled to the at least one acoustic driver, the first cavity having a first acoustic port formed therein, the second cavity having a second acoustic port formed therein, the at least one acoustic driver radiating sound having a phase difference to the outside through the first acoustic port and the second acoustic port, wherein,
Within a target frequency band, the acoustic output device exhibits directivity to far-field radiated sound as represented by sound emitted from the first acoustic port and the second acoustic Kong Fu having a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions, an
The ratio of the surface acoustic load of the first acoustic port to the second acoustic port is in the range of 0.5-3.5.
12. An acoustic output device comprising:
at least one acoustic driver;
a first cavity and a second cavity acoustically coupled to the at least one acoustic driver, the first cavity having a first acoustic port and the second cavity having a second acoustic port, the at least one acoustic driver radiating sound having a phase difference to the outside through the first acoustic port and the second acoustic port, the rate of change of the phase difference being less than 30 DEG/oct in a frequency range of 1kHz-8kHz, wherein,
within a target frequency band, the acoustic output device exhibits directivity to far-field radiated sound as if the sound emitted from the first acoustic port and the second acoustic Kong Fu has a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions.
13. An acoustic output device comprising:
At least one acoustic driver;
a first cavity and a second cavity acoustically coupled to the at least one acoustic driver, the first cavity having a first acoustic port formed therein, the second cavity having a second acoustic port formed therein, the at least one acoustic driver radiating sound having a phase difference to the outside through the first acoustic port and the second acoustic port, wherein,
within a target frequency band, the acoustic output device exhibits directivity to far-field radiated sound as represented by sound emitted from the first acoustic port and the second acoustic Kong Fu having a far-field sound pressure level difference of not less than 3dB in at least one pair of opposite directions, an
The ratio of the open area of the first acoustic port to the second acoustic port is in the range of 0.5-2.
CN202321538845.7U 2023-03-24 2023-06-15 Acoustic output device Active CN220755030U (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
CNPCT/CN2023/083554 2023-03-24
CN2023083553 2023-03-24
CN2023083554 2023-03-24
CNPCT/CN2023/083553 2023-03-24

Publications (1)

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CN220755030U true CN220755030U (en) 2024-04-09

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CN202321538845.7U Active CN220755030U (en) 2023-03-24 2023-06-15 Acoustic output device

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CN (1) CN220755030U (en)

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