Mass loaded earplugs with ventilated chamber

Abstract

The present application relates to a mass-loaded earplug with a ventilated chamber. An intra-concha earphone is disclosed. In an embodiment, the intra-concha earphone includes a housing having a rear space, which is divided into a rear cavity volume, a bass duct, and a ventilated chamber between a driver and a rear wall. The ventilated chamber can be acoustically coupled to the rear cavity volume through both an acoustic port and a bass duct. In addition, the ventilated chamber can be acoustically coupled to the surrounding environment through a vent port, wherein the vent port can be the only acoustic opening in the rear wall. Therefore, the sound emitted by the driver can propagate through the acoustic port and the bass duct to meet in the ventilated chamber before being released to the surrounding environment through the vent port. Other embodiments are also described and claimed.

Description

[0001] This application is a divisional application of a divisional application with an application date of June 26, 2015, application number 201811085882.0, and invention name “Mass-loaded earplug with ventilation chamber”.

[0002] Divisional application 201811085882.0 is a divisional application of the invention patent application with application date of June 26, 2015, application number 201510362022.7 and invention name “Mass-loaded earplug with ventilation chamber”. Technical Field

[0003] Embodiments are disclosed that relate to headphones. More specifically, embodiments are disclosed that relate to an intra-concha earphone having a rear space divided into a back volume, a bass duct having an acoustic mass, and a ventilated chamber. In embodiments, the ventilated chamber may be acoustically coupled to the back volume and the bass duct and may be terminated to the surrounding environment through a single rear port. Background Art

[0004] Concha earphones, also known as earplugs, are headphones that are placed in the outer ear. During use, the concha earphones can face the ear canal, but are generally not inserted into the ear canal. Because concha earphones are generally not sealed within the ear canal, sound can leak out of the earphone without reaching the ear canal. In addition, sound from the surrounding environment can travel around the earphone into the ear canal, further degrading the acoustic performance. Because sound leakage can depend on the anatomical structure of the user's ear, the acoustic performance of concha earphones can be inconsistent in all usage scenarios. Summary of the invention

[0005] Embodiments of concha earphones are disclosed. In embodiments, the concha earphones include a housing that holds a driver that converts an electrical audio signal into sound. The housing may have a rear wall located behind the driver and may define a rear space between the driver and the rear wall. A chamber baffle may be located in the rear space and may divide the rear space into several spaces, including a rear cavity volume behind the driver, a ventilation chamber between the chamber baffle and the rear wall, and a bass duct. The chamber baffle may also define one or more ports or holes, such as an acoustic port that acoustically couples the rear cavity volume with the ventilation chamber, and a bass hole from which the bass duct at the rear cavity volume extends to a duct port at the ventilation chamber. The rear wall may include a ventilation port so that the ventilation chamber is acoustically coupled to the surrounding environment through the ventilation port. In addition, the ventilation port may be the only acoustic opening in the rear wall of the housing. Therefore, a first portion of the sound emitted by the driver may propagate through the acoustic port and a second portion of the sound may propagate through the bass duct so that the sound portions meet in the ventilation chamber before leaving the housing through the ventilation port.

[0006] The chamber baffle may include a front surface facing the driver and a rear surface facing the rear wall. The front surface may at least partially define the rear chamber and the rear surface may at least partially define the vent chamber. In addition, a duct profile in the rear surface may define a bass duct between the chamber baffle and the rear wall. In an embodiment, the duct profile follows a curvilinear path on the rear surface between the bass hole and the bass port. The bass port may be positioned across the vent chamber from the acoustic port, for example the ports may be separated by less than 1 mm so that sound passing through the acoustic port and the duct port enters the vent chamber at approximately the same location.

[0007] In an embodiment, one or more ports or holes in the earphone are covered with an acoustic material. For example, the acoustic port, the duct port and / or the ventilation port may be covered with a mesh material. Each port, covered or uncovered, may present an acoustic impedance based on the geometry of the port, the covering material, and the like. In an embodiment, the acoustic port has an acoustic impedance that is higher than the acoustic impedance of both the duct port and the ventilation port. For example, the acoustic port may have an acoustic impedance that is at least 25 times the acoustic impedance of the ventilation port. The acoustic impedance of the ventilation port may be lower than about 10Rayl, thereby substantially not hindering the propagation of sound toward the surrounding environment. However, due to the protective shield that covers the port and reduces the possibility of foreign matter invading the earphone from the surrounding environment, the ventilation port or any other port or hole may have a non-zero acoustic impedance relative to the open air.

[0008] In addition to providing an acoustic network within the earphone, the one or more chambers formed by the chamber baffles may also hold components for acoustic control. For example, a microphone may be located in the ventilated chamber to sense sound from the surrounding environment. Thus, the microphone may provide a signal that can be processed by the earphone to achieve effective noise control.

[0009] The above summary does not include an exhaustive list of all aspects of the invention. It is contemplated that the invention includes systems and methods that can be practiced in all suitable combinations of the various aspects summarized above and disclosed in the following detailed description and especially those aspects claimed in the claims filed with this application. Such combinations have specific advantages not specifically set forth in the above summary. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a perspective view of an earphone having multiple acoustic openings in a rear portion of a housing according to an embodiment of the present invention.

[0011] Figure 2 is a cross-sectional view of an earphone having a plurality of acoustic openings in a rear portion of a housing according to an embodiment of the present invention.

[0012] Figure 3 is a schematic diagram of an earphone having multiple acoustic openings in a rear portion of a housing according to an embodiment of the present invention.

[0013] Figure 4 is a perspective view of an earphone having a single acoustic opening in a rear portion of a housing according to an embodiment of the present invention.

[0014] Figure 5 is an exploded view of an earphone having a single acoustic opening in the rear portion of the housing according to an embodiment of the present invention.

[0015] Figure 6 is a cross-sectional view of an earphone having a single acoustic opening in a rear portion of a housing according to an embodiment of the present invention.

[0016] Figure 7 is a front perspective view of a chamber baffle according to an embodiment of the present invention.

[0017] Figure 8 is a rear perspective view of a chamber baffle according to an embodiment of the present invention.

[0018] Fig. 9 is a schematic diagram of an earphone having a single acoustic opening in a rear portion of a housing according to an embodiment of the present invention.

[0019] Fig.10 is a schematic diagram of an earphone having a single acoustic opening in a rear portion of a housing according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] Embodiments of the present invention describe headphones for playing externally generated audio signals received from an external audio source. However, while some embodiments are described specifically with respect to concha earphones, the embodiments are not limited thereto, and some embodiments may also be applicable to other uses. For example, one or more embodiments described below may be integrated into other devices or apparatuses that direct sound into the ear, such as an in-ear canal earphone that is typically sealed relative to the ear canal.

[0021] In various embodiments, description is made with reference to the accompanying drawings. However, some embodiments may be implemented without one or more of these specific details, or may be combined with other known methods and configurations. In the following description, various specific details, such as specific configurations, dimensions, and processes, are described to provide a thorough understanding of the embodiments. In other cases, well-known processes and manufacturing techniques are not described in specific details to avoid unnecessarily obscuring the description. Throughout this specification, references to "one embodiment", "one embodiment", etc. refer to specific features, structures, configurations, or characteristics described that are included in at least one embodiment. Therefore, the appearance of phrases "one embodiment", "one embodiment", etc. throughout this specification in various locations does not necessarily refer to the same embodiment. In addition, specific features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments.

[0022] In one aspect, the concha earphone includes a housing having a rear space that is divided into a rear cavity volume, a bass duct, and a ventilation chamber located between a driver and a rear wall. The ventilation chamber can be acoustically coupled to the rear cavity volume through both an acoustic port and a bass duct. In addition, the ventilation chamber can be acoustically coupled to the surrounding environment through the ventilation port. Sound emitted by the driver can propagate through the acoustic port and the bass duct so as to meet in the ventilation chamber when released to the surrounding environment through the same ventilation port. Because the ventilation port may be the only opening in the rear wall, such as a single externally visible opening in the rear wall, the possibility of foreign matter intruding into the earphone can be reduced.

[0023] On the one hand, the chamber baffle in the housing can define the geometry of the rear cavity volume, the bass duct, and the ventilation chamber. Therefore, the chamber baffle can control the acoustic quality of the volume in the earphone by size design and configuration. In addition, the chamber baffle can define an acoustic path for acoustic coupling of the driver with the surrounding environment. The acoustic path can include an acoustic port between the rear cavity volume and the ventilation chamber, a bass hole between the rear cavity volume and the bass duct, a bass port between the bass duct and the ventilation chamber, or a ventilation port that exits to the surrounding environment. Therefore, the chamber baffle can control the acoustic impedance of each acoustic path by size design and configuration. The acoustic impedance of the ports and holes in the earphone can be changed by one or more acoustic materials covering the ports, such as a mesh. Therefore, the chamber baffle and other acoustic elements of the earphone can be configured to achieve the desired resonance of the driver and tune the frequency response and bass response of the earphone to the desired level. Because the desired acoustic performance can be achieved using an acoustic network assembled in the rear space of the earphone, the bass duct radiating from the rear space can be eliminated, and the earphone can be compactly packaged.

[0024] refer to Figure 1 , shows a perspective view of an earphone having multiple acoustic openings in the rear portion of the housing according to an embodiment of the present invention. The earphone 100 can be configured to be connected to an electronic device, such as a portable media player or another device capable of playing audio, video or other media. For example, the earphone 100 can include an audio jack or other electronic connector that electrically connects the electronic device to the cable 102. Thus, an externally generated audio signal can be transmitted to a driver in the housing 104 of the earphone 100 via the cable 102. The driver can convert the electronic audio signal into sound. In an alternative embodiment, the earphone 100 incorporates a wireless interface to receive the externally generated audio signal via a wireless connection to an external amplifier.

[0025] The housing 104 can be sized and configured to be placed in the outer ear of the ear without sealing the ear canal of the ear. Thus, the housing 104 can include a front wall 106 configured to face the ear canal and a rear wall 108 configured to approximate the contour of the outer ear so that the earphone 100 resists movement from the ear. When placed in the outer ear, the driver in the housing 104 can emit sound forward through the front acoustic opening 110 in the front wall 106 and into the ear canal. In addition to emitting sound in the forward direction through the front acoustic opening 110, the sound generated by the driver can also be emitted in the rearward direction through the tuning port 112 and the bass port 114.

[0026] refer to Figure 2, shows a cross-sectional view of an earphone having a plurality of acoustic openings in the rear portion of the housing according to an embodiment of the present invention. The front wall 106 may be defined as the portion of the housing 104 extending forward from the driver 202, and the rear wall 108 may be defined as the portion of the housing 104 extending behind the driver 202. For example, the transverse plane may pass orthogonally to the central axis of the driver 202, and the front wall 106 may be the portion of the housing 104 axially located in front of the transverse plane, and the rear wall 108 may be the portion of the housing 104 axially located behind the transverse plane. The rear chamber 204 may be located between the driver 202 and the rear wall 108 in the housing 104. Therefore, the sound emitted from the driver 202 in the rearward direction may be directed to the tuning port 112 formed by the rear wall 108 at the rear chamber 204, and to the acoustic channel 206 entering the acoustic duct 208 from the rear chamber 204. The sound directed to the acoustic channel 206 may be propagated to the bass port 114 through the acoustic duct 208.

[0027] refer to Figure 3 , shows a schematic diagram of an earphone having multiple acoustic openings in the rear portion of the housing according to an embodiment of the present invention. The sound emitted by the driver 202 into the rear chamber 204 may include a first sound portion 302 directed toward the tuning port 112 and a second sound portion 304 directed toward the acoustic channel 206. More specifically, the first sound portion 302 is output to the surrounding environment through a first location of the rear wall 108, namely the tuning port 112, and the second sound portion 304 propagates through the acoustic duct 208 and is output to the surrounding environment through a second location of the rear wall 108, namely the bass port 114. The first sound portion 302 and the second sound portion 304 do not mix within the earphone 100 after leaving the rear chamber 204 or before being emitted from the housing 104 to the surrounding environment. Thus, the rear wall 108 includes at least two externally visible openings corresponding to the tuning port 112 and the bass port 114, and thus foreign matter, such as dust, debris, and other particles, can enter the earphone 100 through the rear wall 108 at multiple locations.

[0028] Having described the structure and acoustic function of an earphone 100 having multiple acoustic openings in the rear wall 108, the following description will focus on embodiments of an earphone 100 having a vent chamber that terminates to the surrounding environment through a single acoustic opening in the rear housing wall. However, it should be understood that the embodiments of the invention described herein are not mutually exclusive, and therefore, within the scope of the present invention, features of an earphone 100 having multiple acoustic openings in the rear wall 108 may be combined with features of an earphone 100 having a single acoustic opening in the rear housing wall.

[0029] refer to Figure 4, shows a perspective view of an earphone having a single acoustic opening in the rear portion of the housing according to the described embodiment. The earphone 100 can be configured to receive an externally generated audio signal through the cable 102 and convert the electronic audio signal into sound played by the driver 202 in the housing 104 through the front acoustic opening 110 in the front wall 106. The earphone 100 can have a housing 104 that is sized and configured to be placed within the concha of the ear. Thus, during use, sound can be played into the ear through the front acoustic opening 110.

[0030] Similar to the above reference Figure 1 and 2 In the described embodiment, the driver 202 may also emit sound in a rearward direction toward the rear wall 108. However, in an embodiment, the acoustic mass of the acoustic duct 208 may be integrated into the rear wall 108 behind the driver 202 along with the rear chamber 204. More specifically, sound may be routed through an acoustic network axially located behind the driver 202 and in the rear wall 108. Figure 1 and 4 A comparison of the earphone 100 embodiments shown in indicates that incorporating an acoustic network in the rear wall 108 in this manner may allow for a more compact earphone 100.

[0031] Reference now Figure 4 , the sound emitted by the driver 202 at the rear can be discharged from the housing 104 through the ventilation port 402 in the rear wall 108. More specifically, the rear wall 108 can include an externally visible acoustic opening through which the sound emitted by the driver 202 at the rear meets the surrounding environment. That is, multiple acoustic channels can be routed to meet in the housing 104 so that multiple ventilation ports can be uniformly ventilated from the housing 104 at a single visible location. Therefore, in an embodiment, the ventilation port 402 provides a unique acoustic opening in the rear wall 108.

[0032] refer to Figure 5 , shows an exploded view of an earphone having a single acoustic opening in the rear portion of the housing according to an embodiment of the present invention. The various components of the earphone 100 can be aligned along an earphone axis 502. The earphone axis 502 can be defined as an axis passing through the center of the driver 202. That is, the outer edge 504 of the driver 202 can be axially aligned with the earphone axis 502. For example, in an embodiment, the outer edge 504 is circular and centered on the earphone axis 502. In addition, the outer edge 504 can be concentric with the diaphragm 506 of the driver 202, so that sound emitted by the diaphragm 506 in a forward or rearward direction initially propagates along the earphone axis 502. The front wall 106 of the housing 104 can be located in front of the driver 202 along the earphone axis 502, and the rear wall 108 of the housing 104 can be located behind the driver 202 along the earphone axis 502.

[0033] In an embodiment, one or more components may be located in the housing 104 between the driver 202 and the rear wall 108 to divide the volume of the space in the housing 104 into a plurality of chambers or volumes. For example, a chamber baffle 508 may be located between the driver 202 and the rear wall 108. The chamber baffle 508 may have a shape that conforms to the housing 104 and / or seals the housing 104 in such a manner that a number of volumes or chambers are defined between a surface of the chamber baffle 508 and a surface of the driver 202 or the rear wall 108. For example, a chamber may be defined between the driver 202 and a front surface of the chamber baffle 508. The rear surface of the chamber baffle 508 may have a duct profile 510, such as a concave profile that extends along a path to form a groove or channel along the rear surface. The duct profile 510 may cooperate with the inner surface of the rear wall 108 to form an acoustic channel having the acoustic mass of air, such as a bass pipe. Several volumes can be further placed in fluid communication with each other, i.e., acoustically coupled to each other, through various ports, such as acoustic ports 512 or bass holes 514. Because several independent volumes can be defined by one or more chamber baffles 508, the frequency response and bass response of the acoustic network can be changed by changing the shape of the baffles. In addition, since the various volumes can be acoustically coupled through one or more ports or holes, the frequency response and bass response of the acoustic network can be changed by controlling the acoustic impedance of the ports and holes. Thus, mesh elements can cover the ports to change their acoustic impedance. For example, an acoustic mesh 516 can cover the acoustic port 512 and a ventilation mesh 518 can cover the ventilation port 402. The mesh can include edges that mate with corresponding edges of the ports so that the cross-sectional area of ​​the port is filled to cover the port.

[0034] refer to Figure 6 , shows a cross-sectional view of an earphone having a single acoustic opening in the rear of the housing according to an embodiment of the present invention. The rear space may include the entire volume between the driver 202 of the earphone 100 and the rear wall 108. Therefore, the rear space may be defined by the space surrounded by the opposing surfaces of the driver 202 and the rear wall 108. The housing 104 may support the driver 202 around the outer edge 504 so that the front of the driver 202 faces the front wall 106 and the rear of the driver 202 faces the rear space. Thus, the rear wall 108 of the housing 104 may enclose the rear space behind the driver 202. Therefore, as discussed above, when an externally generated audio signal is delivered to the driver 202 via the cable 102 (the cable may extend through the rear space to attach to the driver 202), the electrical signal may be converted into sound by the driver 202, and the sound is emitted forward to the front acoustic opening 110 and emitted backward into the rear space.

[0035] In an embodiment, chamber baffle 508 resides in the rear space and includes a shape that divides the rear space into one or more volumes. In an embodiment, chamber baffle 508 can be assembled from multiple parts and / or can be multiple chamber baffles 508 that subdivide the rear space, but for ease of understanding, chamber baffle 508 is described below as essentially comprising a single body whose surface geometry creates an acoustic network of chambers and conduits in the rear space that are acoustically coupled through one or more ports and / or holes.

[0036] The chamber baffle 508 may include a front surface 602 facing the driver 202. The front surface 602 may define a rear cavity volume 604 behind the driver 202 and between the driver 202 and the chamber baffle 508. The rear cavity volume 604 may be a sub-volume of the rear space. The rear cavity volume 604 may substantially include a cavity having a volumetric geometry that depends on the surfaces of the driver 202, the rear wall 108, and the chamber baffle 508. That is, those surfaces may surround and thus define the rear cavity volume 604. For example, the chamber baffle 508 may have a concave front surface 602 that defines a corresponding convex portion of the rear cavity volume 604. That is, the spatial envelope of the rear cavity volume 604 may be a negative space that conforms to the front surface 602. The size and shape of the rear cavity volume 604, as defined by the surfaces that surround the volume, may be important to the overall acoustic performance of the earphone 100. More particularly, the cavity of the rear cavity volume 604 may tune the frequency response of the earphone 100. In particular, the size of the back cavity volume 604 formed between the driver 202, the back wall 108 and the chamber baffle 508 can determine the resonance of the earphone 100 in a frequency range of, for example, about 2 kHz to about 3 kHz, i.e., the open ear gain. The ear canal generally acts like a resonator and has a specific resonant frequency when open and a different resonant frequency when closed. The acoustic response at the ear drum when the ear canal is open is called the open ear gain. The resonant frequency of about 2 kHz to 3 kHz is generally preferred by users. The back cavity volume 604 can be shaped to tune the resonance of the earphone 100 to frequencies within this range. More specifically, when the back wall 108 or the chamber baffle 508 is shaped to reduce the back cavity volume 604, the frequency of the open ear gain can be increased. As an example, the back cavity volume 604 can be reduced by reducing the radius of the back wall 108 that laterally surrounds the back cavity volume 604 about the earphone axis 502. Alternatively, the back cavity volume 604 can be reduced by reducing the distance between the chamber baffle 508 and the driver 202 along the earphone axis 502. Conversely, when the back wall 108 or the chamber baffle 508 is shaped to increase the back cavity volume 604, the frequency of the open ear gain can be reduced. As an example, the back cavity volume 604 can be increased by increasing the radius of the back wall 108 that laterally surrounds the back cavity volume 604 about the earphone axis 502. Alternatively, the back cavity volume 604 can be increased by increasing the distance between the chamber baffle 508 and the driver 202 along the earphone axis 502. Thus, the geometry of the back cavity volume 604 can be adjusted to tune the resonance and acoustic performance of the earphone 100.

[0037] The chamber baffle 508 may also define one or more ports or holes that connect the rear cavity volume 604 with one or more additional volumes located behind the chamber baffle 508 from the rear cavity volume 604. The additional volumes may be other sub-volumes of the rear space. The rear space in the housing 104 may be subdivided to include a bass duct 606 that is acoustically coupled to the rear cavity volume 604 through a bass port 514. In an embodiment, the bass port 514 may be a hole formed through the chamber baffle 508 (see Figure 5 However, the bass hole 514 may also be a port defined between the outer edge of the chamber baffle 508 and the inner surface of the rear wall 108 (similar to Figure 5 ). Thus, the bass hole 514 may provide a passage connecting the back volume 604 with the bass duct 606.

[0038] Similar to the rear cavity volume 604, the bass duct 606 can be defined as the volume of the space between the rear surface 608 of the chamber baffle 508 and the inner surface of the rear wall 108. The bass duct 606 can be a sub-volume of the rear space. That is, the bass duct 606 can basically include a cavity having a volume geometry that depends on the surface of the rear wall 108 and the chamber baffle 508 surrounding the bass duct 606. For example, the chamber baffle 508 can define a duct structure that extends away from the rear cavity volume 604 at the bass hole 514. In addition to defining the duct, the chamber baffle 508 can also define a duct port 612 at the end of the bass duct 606. For example, the duct port 612 can be defined between the rear surface 608 and the rear wall 108, which can be combined to create a port shape. The surface of the cavity defining the bass duct 606 can be sized and shaped to tune the bass response of the driver 202. Just as the dimensions of the chamber baffle 508 can be altered to control the geometry of the back volume 604 and thereby the resonance of the earphone 100, the dimensions of the chamber baffle 508 can be altered to control the geometry of the bass duct 606 and thereby the bass response of the earphone 100. In an embodiment, by shaping the bass duct 606 to contain a volume of air that acts as a corresponding acoustic mass, the bass response can be controlled to frequencies less than 1 kHz.

[0039] The rear space in the housing 104 may also be subdivided to include a ventilated chamber 610 located between the chamber baffle 508 and the rear wall 108. That is, the ventilated chamber 610 may substantially include a cavity having a volumetric geometry that depends on the surfaces of the chamber baffle 508 and the rear wall 108. The ventilated chamber 610 may be a sub-volume of the rear space. The ventilated chamber 610 may be acoustically coupled to the rear cavity volume 604 through both the acoustic port 512 and the bass duct 606. More specifically, the rear cavity volume 604 that tunes the resonance of the earphone 100 may be terminated into the ventilated chamber 610 through the acoustic port 512, and the bass duct 606 that tunes the bass response of the earphone 100 may be terminated into the ventilated chamber 610 through the duct port 612. Thus, the sound transmitted through the rear cavity volume 604 and the bass duct 606 may enter the ventilated chamber 610 and meet or mix therein before being discharged from the housing 104.

[0040] Optionally, the ventilation chamber 610 can be axially located behind the acoustic port 512 in the direction of the earphone axis 502. Similarly, the ventilation chamber 610 can be axially located behind the driver 202 in the direction of the earphone axis 502. For example, the space behind the outer edge 504 can form a cylindrical spatial envelope in the direction of the earphone axis 502. The ventilation chamber 610 can be encompassed by the spatial envelope so that the entire chamber volume is directly behind the driver. Therefore, the ventilation chamber 610 does not add an additional lateral dimension to the earphone 100 in the lateral dimension already formed by the outer edge 504 of the driver 202.

[0041] The transmission of sound from the back cavity volume 604 into the plenum 610 can depend on the geometry of the various interconnected ports and holes. For example, the acoustic impedance of the acoustic port 512 can be changed by changing the size or length of the acoustic port 512 between the back cavity volume 604 and the plenum 610. These dimensions can be changed by adjusting the shape of the chamber baffle 508 and the back wall 108 surfaces that define the acoustic port 512 to achieve the desired acoustic impedance. In addition to modifying the geometry of the chamber baffle 508 and the back wall 108, acoustic materials can be placed over one or more of the various ports or holes.

[0042] In an embodiment, an acoustic mesh 516 is disposed over or in the acoustic port 512 to modify the acoustic performance of the earphone 100. For example, the acoustic mesh 516 may cover the acoustic port 512 to modify the acoustic impedance of the acoustic port 512. In an embodiment, the acoustic mesh 516 is composed of an acoustic material that is acoustically engineered to provide a defined and intended acoustic resistance or filtering effect. For example, the acoustic mesh 516 may be a mesh or foam material that is manufactured to filter certain sound pressure waves emitted by the driver 202 toward the acoustic port 512. Alternatively, the acoustic mesh 516 may be acoustically transparent so as not to substantially interfere with the transmission of sound through the acoustic port 512. In either case, the acoustic mesh 516 may provide a protective barrier that prevents foreign matter, such as dust, water, or other particles, from undesirably entering the back cavity volume 604 from the vent chamber 610.

[0043] Optionally, an acoustic material may be located on or in the duct port 612 or bass port 514 to modify the acoustic performance of the earphone 100, or to prevent unwanted intrusion of foreign matter into the bass duct 606. For example, a duct mesh (not shown) may cover the duct port 612 to modify the acoustic impedance of the bass duct 606. In an embodiment, the duct mesh is composed of an acoustic material that is acoustically engineered to provide a predetermined and intended acoustic resistance or filtering effect. For example, the duct mesh may be a mesh or foam material that is manufactured to filter certain sound pressure waves emitted by the driver 202 through the bass duct 606 toward the duct port 612. Alternatively, the duct mesh may be acoustically transparent so as not to interfere substantially more with the transmission of sound through the duct port 612 than is already inherent in the geometry of the duct port 612. In either case, the duct mesh may provide a protective barrier that prevents foreign matter, such as dust, water, or other particles, from unwantedly entering the bass duct 606 from the plenum 610.

[0044] In an embodiment, the ventilation port 402 can be formed between the ventilation chamber 610 and the surrounding environment through the rear wall 108. The surrounding environment can be the external environment or the environment outside the earphone 100. For example, sound can propagate from the ventilation chamber 610 through the ventilation port 402 to the space within the user's outer ear or into the room in which the user listens to the earphone 100. Thus, the ventilation chamber 610 can be acoustically coupled to the surrounding environment through the ventilation port 402. As described above, the ventilation port 402 can be the only acoustic opening in the rear wall 108, and any rearward sound leaving the housing 104 passes through the opening. Similarly, the ventilation port 402 can constitute the only visible opening in the rear wall 108. That is, the earphone 100 can include only a single opening in the rear wall 108 behind the outer edge 504 visible to the naked eye of the user.

[0045] The vent mesh 518 may be located on or in the vent port 402 to modify the surface area through which sound is transmitted between the vent chamber 610 and the surrounding environment. For example, the vent mesh 518 may be an acoustically transparent material, meaning that it does not affect the acoustic performance of the earphone 100. Alternatively, the acoustic mesh 518 may modify the acoustic performance of the earphone 100 by changing the acoustic impedance of the vent port 402. For example, the material of the vent mesh 518 may be acoustically engineered to provide a predetermined and intended acoustic resistance or filtering effect, such as to filter certain sound pressure waves emitted by the driver 202 through the back volume 604, the bass duct 606, and the vent chamber 610 toward the vent port 402. In either case, the vent mesh 518 may provide a protective barrier that prevents foreign matter, such as dust, water, or other particles, from undesirably entering the housing 104 from the surrounding environment.

[0046] refer to Figure 7 , showing a front perspective view of a chamber baffle according to an embodiment of the present invention. As described above, the chamber baffle 508 may include any geometric shape placed within the rear space between the driver 202 and the rear wall 108 and subdividing the rear space into an acoustic mesh. Thus, the chamber baffle 508 may include a front surface 602 facing the driver 202 and at least partially defining a rear cavity volume 604. As such, the front surface 602 may include a concave shape extending from an edge 702 near the earphone axis 502 to an apex 704. For example, the front surface 602 may include a conical surface having a base perimeter around the edge 702 and a locus at the apex 704. Alternatively, the front surface 602 may include a secondary surface, such as a parabolic surface extending from the edge 702 to the apex 704. The edge 702 may seal against the inner surface of the rear wall 108, such as by adhesive bonding or press-fitting between the edge 702 and the rear wall 108. Thus, the front surface 602 may define a portion of the rear cavity volume 604 having a conforming convex surface. Although the front surface 602 can have a cone shape, it can be similarly shaped as a hemispherical surface, a cubic surface, a pyramidal surface, etc. In addition, the front surface 602 need not be concave, i.e., it can be convex or flat. Therefore, the front surface 602 can have any shape that defines a back cavity volume 604 that gives the earphone 100 the desired acoustic performance.

[0047] One or more ports or holes can be formed through the chamber baffle 508, for example, from the front surface 602 to the back surface 608. The ports or holes can be acoustically calibrated openings or passages that enhance the acoustic performance of the earphone 100. The ports or holes in the earphone 100 can be any shape, including tear-shaped, circular, elliptical, semi-circular, polygonal, etc. It should be appreciated that in some embodiments, any opening through the chamber baffle 508 can have an inlet and outlet defined entirely in the edge 702 of the front surface 602, as shown for the bass port 514, or can have an inlet or outlet defined by a combination of the chamber baffle 508 and another surface such as the back wall 108, as shown for the acoustic port 512. Therefore, the openings connecting the various chambers and conduits in the earphone 100 are not intended to be exclusively limited to the geometric shapes shown in the figures.

[0048] In an embodiment, the acoustic port 512 may be a slot extending from the rim 702 along the slot edge 706 to form a saddle-shaped opening in the direction of the earphone axis 502. As mentioned above, the rim 702 may seal against the inner surface of the rear wall 108, thereby providing a sealed opening for the sound emitted by the driver 202 to pass from the rear cavity volume 604 on the front side of the chamber baffle 508 to the vent chamber 610 on the rear side of the chamber baffle 508.

[0049] The chamber baffle 508 may also include an aperture formed through the wall of the chamber baffle 508 from the front surface 602 to the rear surface 608. For example, the bass port 514 may include a hole through the chamber baffle 508 at a location spaced apart from the acoustic port 512 across the rear cavity volume 604 and / or along the front surface 602. That is, the acoustic port 512 and the bass port 514 may be spaced apart along the chamber baffle 508 so as to receive and transmit different portions of the sound emitted by the driver 202. Unlike the acoustic port 512, the bass port 514 may be defined between an aperture edge 708 that is entirely in the side 702 of the front surface 602, i.e., the bass port 514 may be an opening, aperture, or hole through the chamber baffle 508 rather than an opening defined by the combination of the rear wall 108 and the slot edge 706.

[0050] The duct profile 510 can substantially constitute a cross-sectional profile of the bass duct 606. That is, the duct profile 510 can be a recessed profile in the rear surface 608 that extends on a path, such as a straight path or a curved path 710, to constitute a groove that passes a certain distance along the rear surface 608. Therefore, when the duct profile 510 is a semi-circular recess in the rear surface 608, the groove along the rear surface 608 can have a semi-cylindrical volume over the straight or curved length. In addition, the bass duct 606 can be defined between the groove and the mating portion of the rear wall 108. Therefore, the bass duct 606 can enclose a certain volume of air, such as a semi-cylindrical volume of air, which acts as an acoustic mass.

[0051] refer to Figure 8 , shows a rear perspective view of a chamber baffle 508 according to an embodiment of the present invention. The duct profile 510 can extend along a straight or curved length between a starting point located at the bass hole 514 and an end point located at the duct port 612, such as along a curved path 710. More particularly, when the rear surface 608 is paired with an opposing surface, such as the rear wall 108, the acoustic mass of the bass duct 606 can become enclosed between the rear wall 108 and the rear surface 608 in the housing 104. Thus, the bass duct 606 can extend from an inlet located at the bass hole 514 to an outlet located at the bass port 612.

[0052] As described above, the acoustic port 512 through the chamber baffle and the duct port 612 between the chamber baffle 508 and the rear wall 108 can be located in the ventilation chamber 610. More specifically, sound can be sent into the ventilation chamber 610 of the assembled earphone 100 through the acoustic port 512 and the duct port 612. In an embodiment, the sound passing through the acoustic port 512 and the duct port 612 can enter the ventilation chamber 610 near the same location. For example, the groove edge 706 that partially defines the acoustic port 512 and the duct profile 510 that partially defines the duct port 612 can span the ventilation chamber 610, or be separated by the separation gap 802 along the rear surface 608 of the chamber baffle 508. In an embodiment, the separation gap 802 is less than the length of the bass duct 606. In an embodiment, the separation gap 802 is less than about 10 mm. For example, the separation gap 802 can be less than 1 mm, such as about 0.1 mm. Thus, sound emitted by driver 202 into back volume 604 may be divided and propagated through both acoustic port 512 and duct port 612 before meeting in plenum chamber 610 and being emitted into the surrounding environment through plenum port 402 .

[0053] refer to Fig. 9, a schematic diagram of an earphone having a single acoustic opening in the rear portion of the housing according to an embodiment of the present invention is shown. The schematic diagram helps to visualize the path of sound through the earphone 100. The earphone 100 may include a driver 202 with its front face pointing toward the front acoustic opening 110 so that the sound emitted by the driver 202 propagates forward into the ear canal. The driver 202 may also emit sound in a rearward direction toward the rear cavity volume 604, and for illustration, the sound may be described as being divided into a first sound portion 902 and a second sound portion 904. The first sound portion 902 may propagate through an acoustic port 512 in the chamber baffle 508 to enter the ventilated chamber 610. The second sound portion 904 may propagate along the rear surface 608 through a bass hole 514 and a bass duct 606 in the chamber baffle 508 before entering the ventilated chamber 610. Thus, the first sound portion 902 and the second sound portion 904 may enter the ventilated chamber 610 after leaving the rear cavity volume 604 through their respective ports or holes, where they meet or mix. More specifically, the first sound portion 902 and the second sound portion 904 can enter the same ventilation chamber 610 before being released into the surrounding environment. Thus, the first sound portion 902 and the second sound portion 904 can propagate from the driver 202 in separate directions and then mix at the same location in the ventilation chamber 610 to combine into the output sound 906 emitted from the earphone 100 through the ventilation port 402.

[0054] refer to Fig.10, shows a schematic diagram of an earphone having a single acoustic opening in the rear portion of the housing according to an embodiment of the present invention. The schematic diagram helps visualize one way that the first sound portion 902 or the second sound portion 904 can follow a tortuous path between the rear cavity volume 604 and the ventilated chamber 610. However, the sound propagated through the earphone 100 can follow a tortuous path along any segment of the acoustic network, such as even from the ventilated chamber 610 to the surrounding environment. As described above, the first sound portion 902 can be emitted by the driver 202 into the ventilated chamber 610 through the acoustic port 512. Similarly, the second sound portion 904 can be emitted by the driver 202 toward the bass hole 514. The second sound portion 904 can propagate from the bass hole 514 through the bass duct 606 toward the duct port 612 to enter the ventilated chamber 610. In an embodiment, the bass duct 606 is defined by a duct profile 510 that follows a curved path 710 along the rear surface 608. For example, the curved path 710 can be a tortuous path with multiple turns, where the turns can be 90 degrees or more. The tortuous path may also include a single turn or curve extending over the entire path length, wherein the total path length is at least three times the linear distance between the bass hole 514 and the duct port 612. For example, the bass duct 606 may spirally wrap around the earphone axis 502 along the rear surface 608 from the bass hole 514 to the adjacent duct port 612. That is, the spiral may follow the path 710. The first sound portion 902 and the second sound portion 904 may meet in the vent chamber 610 and combine into an output sound 906 that is then released to the surrounding environment through the vent port 402.

[0055] As described above, the acoustic ports, holes, and conduits can be dimensionally designed to tune the acoustic performance of the earphone 100. In addition, additional components, such as meshes placed over the ports and holes, can be used to tune the acoustic performance. One skilled in the art can introduce additional components to further modify the acoustic response of the acoustic network, such as by implementing baffles or other acoustic materials along the surface, or hanging in the conduits or chambers. Such additional components can also further modify the propagation of sound through the earphone 100. Therefore, in order to be compatible with a given specification or design parameter, the ports, holes, conduits, and chambers in the earphone 100 are calibrated in the sense that they have been tested or evaluated in at least one specimen of a manufacturing batch. In other words, the acoustic network of the earphone 100 is not made of random openings or grooves, but is intentionally formed to modify the acoustic performance of the earphone 100 in a manner that tunes the resonance, frequency response, and bass response of the earphone 100. The acoustic tuning parameters can be tuned by changes in the various structures described above. Some of these parameters will now be pointed out, but it should be understood that the following discussion of specific acoustic features can be changed within the scope of the present description and is therefore not intended to limit the present invention.

[0056] In an embodiment, each hole and port of the earphone 100 may include a specific acoustic impedance. Acoustic impedance affects how sound propagates through an acoustic medium, such as air, and is therefore useful as a tuning parameter that affects, for example, the resonant frequency of the earphone 100. The acoustic impedance may be determined based on the geometry and material of the port or hole, as well as the geometry and material of another component (e.g., acoustic mesh 516 or vent mesh 518) that obscures a portion of the hole or port. Thus, the acoustic impedance of the hole or port may be tuned as desired.

[0057] In an embodiment, the acoustic impedance of the acoustic port 512 and / or the acoustic mesh 516 above the acoustic port 512 is tuned to be higher than the acoustic impedance of the ventilation port 402 and / or the ventilation mesh 518 above the ventilation port 402. For example, the acoustic port 512 can have a smaller diameter than the ventilation port 402, or the acoustic mesh 516 can have a higher mesh surface area to port cross-sectional area ratio than the ventilation port 402, such as a higher packing density. Thus, sound propagation through the back cavity volume 604 can be more resisted than sound propagation through the ventilation port 402, so that sound entering the ventilation chamber 610 is freely released to the surrounding environment. In an embodiment, the acoustic impedance of the acoustic port 512 and / or the acoustic mesh 516 can be at least 25 times greater than the acoustic impedance of the ventilation port 402 and / or the ventilation mesh 518. For example, the acoustic impedance of the acoustic port 512 and / or the acoustic mesh 516 may be 50 to 100 times the acoustic impedance of the vent port 402 and / or the vent mesh 518 .

[0058] The acoustic impedance of other ports and holes in the earphone 100 can be similarly tuned. For example, the conduit port 612 and / or the conduit mesh above the conduit port 612 can also have an acoustic impedance, and in an embodiment, the acoustic impedance of the conduit port 612 and / or the conduit mesh can be tuned to be higher than the acoustic impedance of the vent port 402 and / or the vent mesh 518. Conversely, the acoustic impedance of the conduit port 612 and / or the conduit mesh can be tuned to be lower than the acoustic impedance of the acoustic port 512 and / or the acoustic mesh 516.

[0059] Each chamber or volume within the earphone 100 may also include an acoustic impedance. For example, the bass duct 606 may have an acoustic impedance based on the acoustic mass of the bass duct 606 and the acoustic losses (e.g., viscous and thermal losses that occur when sound passes through the bass duct 606). As described above, the bass duct 606 may contain a volume of air that acts as an acoustic mass. Acoustic mass can be conceptualized as the mass of the diaphragm 506 added to the driver 202. Therefore, the acoustic mass can be sized based on the geometry of the bass duct 606 to affect the resonance and bass response of the driver 202. For example, the higher the acoustic mass of the bass duct 606, the lower the resonance of the earphone 100 and the more bass. However, the size of the acoustic mass of the bass duct 606 may be limited because the driver 202 must be large enough to drive the acoustic mass, and therefore, cost and packaging size considerations may impose practical limitations on driver selection. Once the appropriate acoustic mass is selected to create the desired resonance and bass response for the actual driver 202, the geometry of the bass duct 606 can be optimized to fit in the available rear space. For example, in order to nail the acoustic quality at a desired value, when the length of the bass duct 606 is shortened to fit behind the chamber baffle 508, the area of ​​the duct profile 510 must be reduced. However, the reduction in size of the bass duct 606 becomes limited by viscosity and thermal losses, which increase roughly in proportion to the negative square of the area of ​​the duct profile 510, thereby increasing the acoustic impedance of the bass duct 606. Therefore, a compromise between the duct size, and thus the earphone size, and the acoustic performance of the bass duct 606 may exist. In an embodiment, the bass duct 606 may be sized so that the acoustic losses through the bass duct 606 are approximately twice the acoustic losses through the vent port 402. This may provide a compact earphone with a desired bass response. Thus, the acoustic impedance of the bass duct 606 may be greater than the acoustic impedance of the vent port 402 and / or the vent mesh 518 covering the vent port 402. In an embodiment, the acoustic impedance of each of the bass pipe 606 , the vent port 402 , and / or the vent mesh 518 may be minimized to approximate zero as closely as possible to maintain an acoustic impedance less than that of the acoustic port 512 or the acoustic mesh 516 .

[0060] Even in the case where the acoustic impedance of the port, hole or volume is minimized, the acoustic impedance can still be greater than zero to achieve aesthetic or other functional purposes. For example, the mesh can cover the port to provide visual distinction of the port for aesthetic reasons, and thus, even with a mesh having a small mesh surface area to port cross-sectional surface area ratio, such as less than about 75%, the acoustic impedance of the port can be greater than zero. Similar covering (shrouding) of the port can be used for the functional purpose of reducing the possibility that foreign matter will enter the space behind the headset. For example, as described above, the ventilation port 402 and / or the ventilation mesh 518 can be substantially sound-permeable. For example, the acoustic impedance of the ventilation port 402 and / or the ventilation mesh 518 can be on the order of about 10Rayl, or less. More particularly, the ventilation mesh 518 above the ventilation port 402 can have a plurality of openings whose size is designed to resist the entry of dust, debris, sand or other particles but provide minimal resistance to sound. The plurality of openings can have an effective diameter of about 300 microns or less. For example, the plurality of openings may have an effective diameter of approximately 200 microns, making them small enough to resist the ingress of most sand particles, but having an acoustic impedance of approximately zero relative to the acoustic impedance of the surrounding atmosphere. In an embodiment, the vent port 402 may be uncovered and particle ingress into the back volume 604 and the bass duct 606 may be resisted by an acoustic mesh 516 over the acoustic port 512 and / or a duct mesh over the duct port 612. In another embodiment, the bass duct 606 may not include a duct mesh, but may be tortuous, such that particles entering the duct port 612 through the vent chamber 610 may not pass all the way through the bass hole 514 to the back volume 604. Thus, both the vent port 402 and the bass port 612 may be uncovered, open passages. Thus, it should be appreciated that the ports and holes of the earphone 100 may be covered or uncovered to create a desired acoustic impedance and reduce the likelihood of particles entering the back volume 604.

[0061] Still reference Fig.10In an embodiment, the headset may include an active noise control element, such as a microphone, an analog circuit, or a digital signal processing component, to reduce unwanted ambient noise. More particularly, an ambient or reference microphone 1002 may be located in the ventilation chamber 610, facing the ventilation port 402 and / or the surrounding environment. The reference microphone 1002 may receive external sound from the surrounding environment and convert the sound into an electrical signal provided to a signal processing circuit system, which may be inside or outside the headset 100. The signal processing circuit system may use an adaptive algorithm to analyze the waveform of the external sound and either phase shift or invert the waveform to create a cancellation signal. The cancellation signal may then be provided to the driver 202, or to an additional speaker located in the headset 100, so that the sound, when traveling toward the ear canal, produces a cancellation sound that destructively interferes with the external sound. The volume of the perceptible external noise may be reduced accordingly. In addition, an error microphone 1004 may be included in the headset 100, such as inside or outside the front wall 106, and may be directed toward the user's ear. Error microphone 1004 may sense sound and return a feedback signal to the signal processing circuitry, which may make additional adjustments to the noise cancellation signal based on a determination of how well the external noise is canceled or in light of other sound quality characteristics determined from the feedback signal.

[0062] In an embodiment, one or both of the reference microphone 1002 or the error microphone 1004 can be used in a telephone application. More specifically, the headset 100 can include a microphone (e.g., the reference microphone 1002) that can be located inside or outside the housing 104 to act as a voice pickup to receive the user's voice. In a telephone usage scenario, the received sound can be converted by the microphone into an electrical signal for further processing.

[0063] In the foregoing description, the invention has been described with reference to specific exemplary embodiments thereof. It will be apparent that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. Thus, the description and drawings should be regarded in an illustrative rather than a restrictive sense.

Claims

1. A headset, comprising: a housing including a vent port as the only acoustic opening in a rear wall; a driver within the housing, wherein the rear wall encloses a rear space behind the driver, and wherein the driver converts electronic audio signals into sound and emits the sound, the sound exiting the rear space through the vent port; as well as a baffle in the rear space to divide the rear space into a plurality of volumes, the plurality of volumes including a bass duct extending along a tortuous path to a vent chamber connected to the vent port, wherein a first portion of sound emitted by a driver propagates through the acoustic port to the vent chamber and a second portion of the sound propagates through the bass duct, and wherein the first portion of the sound and the second portion of the sound meet in the vent chamber before exiting the housing through the vent port.

2. The earphone of claim 1, wherein the curved path extends along a rear surface of the partition.

3. The earphone of claim 1, wherein the plurality of volumes includes a back volume between the driver and the baffle, and wherein the baffle includes an acoustic port and a bass port facing the back volume.

4. The earphone of claim 3, wherein the bass duct routes the sound from the rear volume to the vent port.

5. The earphone according to claim 3, wherein the bass duct seals off a volume of air between a bass hole formed by the baffle to the rear volume and a duct port at the vent chamber.

6. The earphone of claim 5, wherein the curved path is a tortuous path extending between the bass port and the duct port.

7. The earphone of claim 1, wherein the ventilation port is the only externally visible opening in the rear wall.

8. A headset, comprising: a housing including a vent port as the only acoustic opening in a rear wall; a driver within the housing, wherein the rear wall encloses a space behind the driver, and wherein the driver converts electronic audio signals into sound and emits the sound, the sound exiting the space through the vent port; as well as A partition in the rear space, wherein the rear surface of the partition has a duct profile that matches the inner surface of the rear wall of the shell and extends to the duct port along the inner surface of the rear wall of the shell, wherein a first part of the sound emitted by the driver propagates through the acoustic port to the ventilation port and a second part of the sound propagates through the duct port to the ventilation port, and wherein the first part of the sound and the second part of the sound meet in a ventilation chamber connected to the ventilation port before leaving the shell through the ventilation port.

9. An earphone according to claim 8, wherein the conduit profile extends along a curved path.

10. The earphone of claim 8, wherein the baffle includes a bass port.

11. The earphone of claim 10, wherein the duct profile forms a bass tube to a duct port to route the sound through a vent chamber to the vent port.

12. The earphone according to claim 11, wherein the bass hole is formed through the partition plate to reach the bass pipe to receive the sound.

13. The earphone of claim 8, wherein the ventilation port is the only externally visible opening in the rear wall.

14. An inner concha earphone, comprising: a housing having an inner surface; a driver within the housing, wherein the inner surface encloses a space behind the driver, and wherein the driver converts electronic audio signals into sound and emits the sound, the sound exiting the space through a vent port in the inner surface; as well as A baffle, the baffle being in the space between the driver and the inner surface, wherein the baffle includes a bass hole and an acoustic port in fluid communication with the ventilation port, wherein a first portion of the sound emitted by the driver propagates through the acoustic port to the ventilation port and a second portion of the sound propagates through the bass hole to the ventilation port, and wherein the first portion of the sound and the second portion of the sound meet in a ventilation chamber connected to the ventilation port before leaving the housing through the ventilation port, and wherein the acoustic port is defined between an outer edge of the baffle and the inner surface of the housing.

15. The concha earphone of claim 14, wherein the baffle includes a groove extending along a rear surface of the baffle from the bass hole to a conduit port connected to the vent chamber.

16. The concha earphone of claim 14, wherein the vent port is the only acoustic port through which sound exits the rear space.

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