PATENT DOCUMENT

Publication Number: US-10469939-B1
Application Number: US-201816126333-A
Country: US
Kind Code: B1

Title: Headphones with tunable dampening features

Abstract:
Headphones are disclosed that include a first earcup assembly. The first earcup assembly includes a first speaker and a plurality of tunable acoustic dampeners at least partially surrounding the first speaker. The plurality of acoustic dampeners are configured to dampen standing wave resonances. The headphones include a second earcup assembly and a headband extending between the first and second earcup assemblies. The headband includes first and second opposing ends attached to the first and second earcup assemblies, respectively.

Claims:
What is claimed is: 
     
       1. A headphone comprising: a first earcup assembly including a first speaker, a plurality of acoustic dampeners at least partially surrounding the first speaker and a front volume housing extending along a back side of the plurality of acoustic dampeners, the plurality of acoustic dampeners being configured to dampen standing wave resonances at one or more frequencies in a range of 7 to 9 kHz and wherein the plurality of acoustic dampeners includes a plurality of chambers bounded by the front volume housing and a solid film layer having a plurality of openings corresponding to the plurality of chambers, wherein each opening in the plurality of openings is arranged to allow standing waves to enter one of the plurality of chambers; a second earcup assembly; and a headband extending between the first and second earcup assemblies, the headband including first and second opposing ends attached to the first and second earcup assemblies, respectively, wherein the plurality of acoustic dampeners comprise a layer of sound absorbing material and a solid film layer positioned over the layer of sound absorbing material, the solid film layer including a plurality of openings formed therethrough exposing the sound absorbing material. 
     
     
       2. The headphone of  claim 1 , wherein each of the plurality of chambers and its corresponding opening is configured such that standing waves enter the chamber in a first direction and travel therethrough in a second direction, the second direction being non-parallel to the first direction. 
     
     
       3. The headphone of  claim 2 , wherein each of the plurality of chambers and its corresponding opening is configured such that the standing waves travel along a substantially L-shaped path through the plurality of chambers. 
     
     
       4. The headphone of  claim 3 , wherein the plurality of chambers comprises a plurality of sidewalls extending substantially transverse to the front side of the solid film layer. 
     
     
       5. The headphone of  claim 4 , wherein the plurality of chambers comprises an acoustic dampening material positioned with each chamber. 
     
     
       6. The headphone of  claim 1 , wherein the plurality of acoustic dampeners is tuned to dampen standing waves of a same frequency. 
     
     
       7. The headphone of  claim 1 , wherein a first acoustic dampener of the plurality of acoustic dampeners is tuned to dampen a standing wave of a first frequency and a second acoustic dampener of the plurality of acoustic dampeners is tuned to dampen a standing wave of a second frequency, and wherein the first frequency is different from the second frequency. 
     
     
       8. The headphone of  claim 1 , wherein the plurality of acoustic dampeners comprises a plurality of acoustic resonators. 
     
     
       9. The headphone of  claim 8 , wherein the plurality of acoustic resonators comprises a plurality of Helmholtz resonators. 
     
     
       10. The headphone of  claim 1  wherein the first earcup assembly comprises a front volume housing and wherein the front volume housing comprises at least one of a speaker grill and speaker module. 
     
     
       11. The headphone of  claim 1 , wherein the second earcup assembly includes a second speaker and a plurality of acoustic dampeners at least partially surrounding the second speaker, the plurality of acoustic dampeners being configured to dampen standing wave resonances. 
     
     
       12. The headphone of  claim 1 , wherein the plurality of acoustic dampeners encircle a periphery of the first speaker. 
     
     
       13. The headphone of  claim 1 , wherein the plurality of acoustic dampeners encircle a periphery of the second speaker. 
     
     
       14. An over-ear headphone comprising: a headband including first and second opposing ends; a first ear cup assembly coupled to the first end of the headband; a second ear cup assembly coupled to the second end of the headband; wherein each of the first and second ear cup assemblies comprise: an ear cup; an ear cup cushion extending around a periphery of the ear cup; a speaker positioned within the ear cup; and a plurality of acoustic dampeners positioned within a front volume of the ear cup assembly and arranged to at least partially surround a periphery of the speaker, wherein the plurality of acoustic dampeners comprise a layer of sound absorbing material and a solid film layer positioned over the layer of sound absorbing material, the solid film layer including a plurality of openings formed therethrough exposing the sound absorbing material. 
     
     
       15. The over-ear headphone of  claim 14  wherein, in each of the first and second ear cup assemblies: the ear cup includes a driver housing plate; the speaker is coupled to the driver housing plate; and the plurality of acoustic dampeners are coupled to a front surface of the driver housing plate such that the solid film layer is positioned over the driver housing plate. 
     
     
       16. The over-ear headphone of  claim 15  wherein the plurality of acoustic dampeners includes a plurality of chambers bounded on a first side by the front surface of the driver housing plate and bounded by a second side, opposite the first side by the solid film layer, and wherein each opening in the plurality of openings defines a chamber in the plurality of chambers. 
     
     
       17. The over-ear headphone of  claim 16  wherein the plurality of acoustic dampeners include physical sidewalls extending between the front housing plate and the solid film layer that separate individual chambers in the plurality of chambers from each other. 
     
     
       18. The over-ear headphone of  claim 14  wherein the plurality of acoustic dampeners in each ear cup assembly is configured to dampen, within the front volume, standing wave resonances at one or more frequencies in a range of 7 to 9 kHz. 
     
     
       19. An over-ear headphone comprising: a headband including first and second opposing ends; a first ear cup assembly coupled to the first end of the headband; a second ear cup assembly coupled to the second end of the headband; wherein each of the first and second ear cup assemblies comprise: an ear cup including a driver housing plate that includes a front surface that at least partially defines a front volume of its respective ear cup assembly; a back plate coupled to and extending along a back surface of the driver housing plate, opposite the front surface an ear cup cushion extending around a periphery of the ear cup; a speaker positioned within the ear cup; and a plurality of acoustic dampeners formed within the driver housing plate and arranged to at least partially surround a periphery of the speaker, wherein each acoustic dampener in the plurality of acoustic dampeners includes a cavity formed within the driving housing plate, the cavity being defined at least in part by the back plate and having an opening at the front surface of the driver housing plate opposite the back plate. 
     
     
       20. The over-ear headphone of  claim 19  wherein in each of the first and second ear cup assemblies the plurality of acoustic dampeners includes a layer of sound absorbing material disposed over the front surface of the driver housing plate. 
     
     
       21. The over-ear headphone of  claim 19  wherein each cavity in the plurality of acoustic dampeners includes a narrow neck portion at the opening at the front surface leading to a wider portion of the cavity that extends to the back plate. 
     
     
       22. The over-ear headphone of  claim 21  wherein in each of the first and second ear cup assemblies the plurality of acoustic dampeners includes a layer of sound absorbing material disposed over the front surface of the driver housing plate. 
     
     
       23. The over-ear headphone of  claim 19  wherein the plurality of acoustic dampeners in each ear cup assembly is configured to dampen, within the front volume, standing wave resonances at one or more frequencies in a range of 7 to 9 kHz.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     The present application claims the benefit of and priority to U.S. Provisional Application No. 62/565,491, filed Sep. 29, 2017, the entire contents of which are incorporated herein by reference for all purposes. This application is related to co-assigned and concurrently filed U.S. application Ser. No. 16/126,290, entitled “HEADPHONES WITH ACOUSTICALLY SPLIT CUSHIONS”, which claims the benefit of and priority to U.S. Provisional Application No. 62/565,458, filed Sep. 29, 2017, the full disclosures of which are incorporated by reference herein in their entireties for all purposes. 
    
    
     FIELD 
     The described embodiments relate generally to various headphone dampening features. More particularly, the described embodiments relate to headphones having a plurality of tunable dampeners positioned in a front volume thereof. 
     BACKGROUND 
     Over-ear or circumaural headphones have been in use for many years. Over-ear headphones typically include a headband and a pair of earcups attached to opposing ends of the headband which completely encircle or surround a user&#39;s ears when worn. Over-ear headphones can include earcups of a closed-back or open-back design. Closed-back earcups have acoustically sealed or substantially-sealed backs. Open-back earcups have backs acoustically open to ambient environment and noise surrounding the earcups. While closed-back earcups have backs which are acoustically sealed to the ambient environment and noise, the earcups can include one or more vents configured to provide barometric pressure relief. 
     Over-ear headphones with closed-back earcups typically provide good sound isolation because they are sealed or substantially sealed off from ambient noise. However, they can also have certain disadvantages due to the closed design of the earcups. In some closed-back headphones, undesirable or unwanted resonances (e.g., modes) may develop inside a front volume of each respective earcup (e.g., air volume encapsulated inside the earcup or between the earcup and a wearer&#39;s skull and/or ear). Further, standing waves can accumulate in the earcups (e.g., between a driver housing plate of the earcup and a wearer&#39;s skull and/or ear) which can degrade sound quality considerably. Typically, these standing waves can occur in the 7-9 kHz range which can lead to undesirable or unwanted resonance in a frequency response of the headphones. As resonance frequency varies between wearers or users (e.g., due to anatomical differences), such unwanted standing wave resonance may be difficult to equalize with, for example, a digital signal processor (DSP) or graphic equalizer (EQ). As such, there remains a need for headphones with improved dampening features, and in particular, passive acoustic dampeners for closed-back, over-ear headphones. 
     BRIEF SUMMARY 
     The present disclosure describes several improvements related to circumaural headphone designs including designs that have improved passive dampening features that are particularly useful for closed-back over-ear headphones. In some embodiments improved dampening is provided by a plurality of acoustic dampeners disposed in each earcup around a periphery of the earcup speaker. The acoustic dampeners can reduce standing waves (e.g., in about the 7-9 kHz range) that can sometimes develop inside the front volume of a closed-back earcup between a driver housing plate and a user&#39;s skull as a result of the sound isolating design of the earcup. In various embodiments the acoustic dampeners can include resonators tuned to dampen resonance frequencies of standing waves and/or include a sound absorbing material having acoustic properties that absorb such standing wave frequencies as the waves move or are reflect through the sound absorbing material. 
     Headphones are disclosed that include a first earcup assembly. The first earcup assembly includes a first speaker and a plurality of tunable acoustic dampeners at least partially surrounding the first speaker. The plurality of acoustic dampeners are configured to dampen standing wave resonances. The headphones include a second earcup assembly and a headband extending between the first and second earcup assemblies. The headband includes first and second opposing ends attached to the first and second earcup assemblies, respectively. In some embodiments, the second earcup assembly is configured similarly to the first earcup assembly. For example, the second earcup assembly can include a second speaker and a plurality of tunable acoustic dampeners encircling a periphery of the second speaker. 
     In some embodiments, the first earcup assembly includes a front volume housing extending along a back side of the plurality of tunable acoustic dampeners. The plurality of tunable acoustic dampeners may include a plurality of chambers bounded by the front volume housing and a solid film layer having a plurality of openings corresponding to the plurality of chambers formed, wherein each opening in the plurality of openings is arranged to allow standing waves to enter one of the plurality of chambers. In some embodiments, each of the plurality of chambers and its corresponding opening is configured such that standing waves enter the chamber in a first direction and travel therethrough in a second direction, the second direction being non-parallel to the first direction. For example, each of the plurality of chambers and its corresponding opening may be configured such that the standing waves travel along a substantially L-shaped path through the plurality of chambers. In some embodiments, the plurality of chambers includes a plurality of sidewalls extending substantially transverse to the front side of the solid film layer. In some embodiments, the plurality of chambers includes an acoustic dampening material positioned with each chamber. 
     In some embodiments, the first earcup assembly includes a front volume housing and the plurality of tunable acoustic dampeners includes a plurality of perforations in the front volume housing. A back side of the plurality of perforations may be acoustically sealed by a back plate. In some embodiments, opposing ends of each perforation of the plurality of perforations are substantially flush with front and back sides of the front volume housing. In some embodiments, the first earcup assembly includes an acoustic dampening material extending along a front side of the front volume housing. The first earcup assembly may include an acoustic dampening material extending along a back side of the front volume housing. In some embodiments, the plurality of tunable acoustic dampeners includes an acoustic dampening material positioned within each perforation. The plurality of tunable acoustic dampeners may be tuned to dampen standing waves in a frequency range of 7 to 9 kHz. 
     In some embodiments, the plurality of tunable acoustic dampeners is tuned to dampen standing waves of a same frequency. In certain embodiments, a first tunable acoustic dampener of the plurality of tunable acoustic dampeners is tuned to dampen a standing wave of a first frequency and a second tunable acoustic dampener of the plurality of tunable acoustic dampeners is tuned to dampen a standing wave of a second frequency. The first frequency may be different from the second frequency. 
     In some embodiments, the plurality of tunable acoustic dampeners may include a plurality of acoustic resonators. The plurality of acoustic resonators may include a plurality of Helmholtz resonators. In some embodiments, the first earcup assembly includes a front volume housing and wherein the front volume housing includes at least one of a speaker grill and speaker module. The second earcup assembly may include a second speaker and a plurality of tunable acoustic dampeners at least partially surrounding the second speaker, the plurality of acoustic dampeners being configured to dampen standing wave resonances. The plurality of tunable acoustic dampeners may encircle a periphery of the first speaker. In some embodiments, the plurality of tunable acoustic dampeners encircle a periphery of the second speaker. 
     Other aspects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows an over-ear headphone with closed-back earcup assemblies configured in accordance with an embodiment of the present disclosure. 
         FIG. 1B  shows a front perspective view of an earcup assembly of  FIG. 1A . 
         FIG. 2  shows a cross-sectional view of a conventional dampening material positioned on a front surface of a driver housing plate of an over-ear headphone earcup assembly. 
         FIG. 3  shows a cross-sectional view of an over-ear headphone earcup assembly with tunable dampeners configured in accordance with an embodiment of the present disclosure. 
         FIGS. 4A-4B  show top and side views, respectively, of a portion of tunable dampeners configured in accordance with an embodiment of the present disclosure. 
         FIGS. 5A-5B  show top and side views, respectively, of the tunable dampeners of  FIGS. 4A-4B  with sidewalls in accordance with another embodiment of the present disclosure. 
         FIGS. 6A-6B  show top and side views, respectively, of a portion of tunable dampeners configured in accordance with another embodiment of the present disclosure. 
         FIG. 7  shows a cross-sectional view of an over-ear headphone earcup assembly with tunable dampeners configured in accordance with another embodiment of the present disclosure. 
         FIGS. 8A-8B  show top and side views, respectively, of a portion of tunable dampeners configured in accordance with another embodiment of the present disclosure. 
         FIGS. 9A-9B  show top and side views, respectively, of a portion of tunable dampeners configured in accordance with another embodiment of the present disclosure. 
         FIGS. 10A-10B  show top and side views, respectively, of a portion of tunable dampeners configured in accordance with another embodiment of the present disclosure. 
         FIGS. 11A-11B  show cross-sectional views of over-ear headphone earcup assemblies with tunable dampeners configured in accordance with various embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure describes various embodiments of headphones with improved tunable dampeners and associated methods of dampening standing wave resonances in a front volume of closed-back, over-ear or circumaural headphones. 
     Certain details are set forth in the following description and in  FIGS. 1-10B  to provide a thorough understanding of various embodiments of the present disclosure. Other details describing well-known structures and systems often associated with headphones, headphone components, earcup assemblies, speakers, etc., however, are not set forth below to avoid unnecessarily obscuring the description of the various embodiments of the present disclosure. 
     Many of the details, dimensions, angles and other features shown in  FIGS. 1-10B  are merely illustrative of particular embodiments of the present disclosure. Accordingly, other embodiments can include other details, dimensions, angles and features without departing from the spirit or scope of the present disclosure. In addition, those of ordinary skill in the art will appreciate that further embodiments of systems described herein can be practiced without several of the details described below. Various embodiments of the present disclosure can also include structures other than those illustrated in the Figures and are expressly not limited to the structures shown in the Figures. Moreover, the various elements and features illustrated in the Figures may not be drawn to scale. In the Figures, identical reference numbers identify identical or at least generally similar elements. 
     With reference to  FIGS. 1A-1B , an example closed-back, over-ear headphone  100  and an earcup assembly  101  are illustrated, respectively. Earcup assemblies  101  (identified individually as a first earcup assembly  101 A and a second earcup assembly  101 B) are attached to opposing ends of a headband  103  of headphone  100 . Each earcup assembly  101  includes an earcup  102  (e.g., shell, housing) and an earcup cushion  104  (e.g., earpad) extending around an entire periphery of earcup  102 . Each earcup assembly  101  further includes a speaker  105  (e.g., driver, acoustical transducer) configured to produce sound waves. Earcup  102  can include one or more components assembled together (e.g., a housing plate, a back shell or housing, an earcup cushion holder). The speaker  105  can be positioned within or at least partially inside earcup  102 . For example, in some embodiments, speaker  105  is supported within earcup  102  by a driver housing plate  107  (e.g., grille, frame, cover) or other support. 
     As noted above, standing waves (e.g., in about a 7-9 kHz range) can develop inside an earcup (e.g., a front volume) of closed-back, over-ear headphones between a driver housing plate and a user&#39;s skull as a result of the sound isolating design of closed-back, over-ear headphones when in-use. Such standing waves (e.g., traveling along a horizontal or lateral axis) can create a strong resonance in a frequency response of a headphone. As illustrated in  FIG. 2 , a conventional earcup assembly  201  is provided with a layer of sound absorbing material  206  on a driver housing plate  207 . Typically, standing waves have frequencies f governed by the following equation:
 
 f =( n*c )/(2* x )  (Equation 1)
 
Where x is the distance between resonating plates (e.g., driver housing plate and user&#39;s skull and/or ear), c is the sound velocity, and n is the nth order of the standing wave. First order and second order waves  209  and  211  are illustrated in  FIG. 2 .
 
     Typically, in order to provide sufficient dampening, such sound absorbing material  206  would have to be in a thickness range of about 5% to 10% of a wavelength of the standing waves. Sound absorbing material having such a thickness range may require relatively large earcups to accommodate the material. In context of headphones where minimizing or reducing size (e.g., slim headphone design) is important for performance, portability, comfort, or aesthetics, this may be impractical. Therefore, there remains a need for headphones with improved dampening features, and in particular tunable dampeners tuned to dampen such standing wave resonances. 
     With reference to  FIG. 3 , an earcup assembly  301  is shown that is configured in accordance with embodiments of the present disclosure. Earcup assembly  301  can be used with closed-back, over-ear headphones (e.g., headphone  100 ) and replaces conventional earcup assemblies (e.g., earcup assembly  201 ). It should be understood that the Figure illustrates only one of a pair of left and right ear earcup assemblies of a headphone. Thus, each of the features described in reference to earcup assembly  301  illustrated in  FIG. 3  should be understood as applying to the other earcup assembly. 
     Earcup assembly  301  includes one or more same or similar features, in whole or in part, as earcup assembly  101 . For example, earcup assembly includes an earcup  302  and an earcup cushion  304  extending around an entire periphery of earcup  302 . Earcup assembly  301  includes a speaker  305  configured to produce sound waves. Speaker  305  can be positioned within or at least partially inside earcup  302 . In some embodiments, speaker  305  is supported within earcup  302  by a driver housing plate  307  or other suitable support. 
     Earcup assembly  301  further includes a plurality of passive, tunable acoustic dampeners  308  positioned on a front surface  310  of driver housing plate  307 . In other embodiments, tunable dampeners  308  are positioned on a portion of a driver module in addition to or instead of drive housing plate  307 . For example, tunable dampeners  308  can be positioned on a driver module lip or frame (e.g., extending around a periphery of a speaker diaphragm). Generally, tunable dampeners  308  are positioned around or spaced apart from diaphragms of such speakers to minimize interference with sound produced by the speakers, and in some embodiments, tunable dampeners  308  fully surround speaker  305 . 
     Tunable dampeners  308  can be tuned (e.g., configured) to dampen (e.g., match, absorb) standing wave frequencies (e.g., in about a 7-9 kHz range). For example, in some embodiments dampeners  308  are resonators with resonance frequencies that can be tuned to dampen resonance frequencies of standing waves. In other embodiments, dampeners  308  include a dampening or sound absorbing material  306  configured to absorb such standing wave frequencies as such waves move or reflect through material  306 . Further, in some embodiments, tunable dampeners  308  can absorb or be tuned to dampen a single standing wave frequency. However, in other embodiments, tunable dampeners  308  can absorb or be tuned to dampen various or different standing wave frequencies such that a range of standing waves (e.g., more than one frequency) can be dampened. Further details of tunable dampeners  308  are illustrated and described below with respect to  FIGS. 4A-6B . 
       FIGS. 4A-4B, 5A-5B, and 6A-6B  illustrate various dampening features and configurations that can be provided with tunable dampeners  308  of earcup assembly  301  in accordance with embodiments of the present disclosure. For example,  FIGS. 4A-4B  illustrate a plurality of tunable dampeners  408  with a solid film layer  412  (e.g., sheet, cover, liner) positioned over a sound absorbing material  406  (e.g., foam, wool, or other suitable porous dampening material). Solid film layer  412  includes a plurality of openings  414  (e.g., perforations) such that portions  416  of absorbing material  406  underneath solid film layer  412  are uncovered or exposed via such openings  414 . While illustrated as having circular openings  414 , in other embodiments, layer  412  can include other suitably shaped openings. For example, rectangular openings are shown with respect to tunable dampeners  608  described in more detail below with respect to  FIGS. 6A-6B . 
     Openings  414  lead into a plurality of chambers  418  of absorbing material  406 . Further, front surface of  410  of driver housing plate  407  forms a back side or surface of each chamber  418 . In some embodiments, a buffer or intermediary layer is positioned between front surface  410  and back surfaces of chambers  418  (e.g., back surface of absorbing material  406 ). Front surface  410  or an intermediary layer can seal a back side of chambers  418 . 
     Unwanted or undesirable sound waves (e.g., standing wave resonances) enter chambers  418  through openings  414  and are dampened (e.g., energy is absorbed) as such waves move or reflect through absorbing material  406 . In conventional absorbing materials, standing waves generally can enter, move or reflect, and exit such materials along paths substantially parallel to each other. In contrast, sound waves (e.g., standing waves) enter, move or reflect, and exit through chambers  418  along substantially non-parallel paths (e.g., identified with arrows and broken lines P). For example, sound waves can enter chambers  418  along a first direction (e.g., parallel to a lateral axis) and then reflect or travel through chambers in second and/or third directions non-parallel (e.g., transverse, perpendicular, oblique) to the first direction. As such, a distance or path of standing waves moving or reflecting through chambers  418  is increased relative to absorbing materials without a plurality of openings and chambers. This effectively increases a thickness of sound absorbing material  406  relative to a conventional layer of sound absorbing material where sound waves simply enter, move or reflect, and exit through a thickness of the absorbing material. Where as in the present embodiments, sound waves can enter each chamber via openings and travel through a thickness of the chambers but also in multiple directions (e.g., up or down through each chamber) before reflecting back or exiting, effectively increasing paths of the sound waves through the chambers. Effectively increasing a thickness of sound absorbing material  406  by providing a plurality of chambers  418  and/or increasing a path standing waves move or reflect through (e.g., along a non-conventional path), rather than just increasing a thickness of a layer of conventional absorbing material (e.g., thickness of material  206 ), allows for dampening of standing wave resonances while also maintaining a relatively thin or compact headphone design. 
     Chambers  418  are illustrated with “virtual” sidewalls (e.g., identified in broken lines S 1 ). Such sidewalls S are referred to herein as virtual because there are no actual sidewalls or surfaces extending between front housing plate  410  and layer  412 . The plurality of openings  414  allow standing waves to enter chambers  418  and move or reflect as described above. In other embodiments, sidewalls can be included. Dampeners  508  of  FIGS. 5A-5B  are similarly configured as dampeners  408  of  FIGS. 4A-4B . However, dampeners  508  include actual sidewalls (e.g., dividers identified in solid lines S 2 ) extending between front housing plate  510  or other solid buffer/intermediary layer and solid film layer  512 . 
     While illustrated as being filled with sound absorbing material (e.g., material  406  or  506 ), in other embodiments, dampeners  408  or  508  can be provided without such material. As a result, openings  414 ,  514  and chambers  418 ,  518  form a plurality of acoustic resonators (e.g., cavities or hollow spaces). Acoustic resonators can be tuned to a resonance frequency which matches unwanted standing wave frequencies (e.g., to absorb undesirable sounds at their resonance frequencies). In particular, dampeners  408  or  508  can be a plurality of Helmholtz resonators. Generally, a Helmholtz resonator includes a neck portion N that leads into a larger cavity C. Resonance frequency of a Helmholtz resonator depends on a cross-sectional area A and length L of the neck portion N, a volume V of the cavity C, and speed of sound c, according to the following equation: 
     
       
         
           
             
               
                 
                   f 
                   = 
                   
                     
                       c 
                       
                         2 
                         ⁢ 
                         π 
                       
                     
                     ⁢ 
                     
                       
                         A 
                         VL 
                       
                     
                   
                 
               
               
                 
                   ( 
                   
                     Equation 
                     ⁢ 
                     
                         
                     
                     ⁢ 
                     2 
                   
                   ) 
                 
               
             
           
         
       
     
     Therefore, dimensions of neck portion or cavity can be optimized as desired such that dampeners  408  or  508  are tuned to a desired resonance frequency or frequencies to dampen or absorb unwanted standing wave frequencies. For example, a size of cavity C can be increased for each dampener to absorb lower frequencies. 
       FIGS. 6A-6B  illustrate a plurality of dampeners  608  configured in accordance with another embodiment of the present disclosure. Such dampeners  608  include a plurality of rectangular openings  614  in solid film layer  612 . Openings  614  can be offset or positioned off-center from a midline of a corresponding chamber  618 . While illustrated with actual sidewalls S 3 , similar to dampeners  408  and  508 , dampeners  608  can include virtual sidewalls. As illustrated, unwanted standing waves can enter via openings  614  and follow a generally L-shaped path through dampening sound material  606  within each chamber  618 . As with dampeners  408  and  608 , this effectively increases a thickness of sound absorbing material  606  by providing a plurality of chambers  618  standing waves can be absorbed or dampened in. Further, a path of such standing waves is increased (e.g., along the L-shaped path P) relative to waves moving and reflecting back through a conventional layer of absorbing material. In other embodiments, dampeners  608  can include hollow chambers  618  without absorbing material  606  to form resonators tuned to dampen standing waves as described above with respect to dampeners  408  and  508 . 
     With reference to  FIG. 7 , earcup assembly  701  is shown that is configured in accordance with other embodiments of the present disclosure. Earcup assembly  701  can be used with closed-back, over-ear headphones (e.g., headphone  100 ) and replaces conventional earcup assemblies (e.g., earcup assembly  201 ). It should be understood that the Figure illustrates only one of a pair of left and right ear earcup assemblies of a headphone. Thus, each of the features described in reference to earcup assembly  701  illustrated in  FIG. 7  should be understood as applying to the other earcup assembly. 
     Earcup assembly  701  includes one or more same or similar features, in whole or in part, as earcup assembly  301 . For example, earcup assembly  701  includes a plurality of passive, tunable acoustic dampeners  708 . Dampeners  708  can be tuned (e.g., configured) to dampen (e.g., match, absorb) standing wave frequencies (e.g., in about a 7-9 kHz range). In some embodiments dampeners  708  are resonators with resonance frequencies that can be tuned to dampen resonance frequencies of standing waves. In other embodiments, dampeners  708  include a dampening or sound absorbing material  706  configured to absorb such standing wave frequencies as such waves move or reflect through material  706 . Further, in some embodiments, tunable dampeners  708  can absorb or be tuned to dampen a single standing wave frequency. However, in other embodiments, tunable dampeners  708  can absorb or be tuned to dampen various or different standing wave frequencies such that a range of standing waves (e.g., more than one frequency) can be dampened. 
     Rather than being positioned on or over a speaker housing plate or driver module, acoustic dampeners  708  are integrated or formed within driver housing plate  707  and/or in a driver module. For example, such dampeners  708  include holes or cavities drilled, cut, or otherwise machined into or through housing plate  707 . In such embodiments, a thickness of housing plate  707  or a driver module can be utilized for dampening unwanted resonance frequencies without substantially reducing product stiffness (e.g., of earcup assembly  701 ). Generally, tunable dampeners  708  are positioned around or spaced apart from diaphragms of speakers or drivers to minimize interference with sound produced by such speakers. Further details of tunable dampeners  708  are illustrated and described below with respect to  FIGS. 8A-10B . 
       FIGS. 8A-8B, 9A-9B, and 10A-10B  illustrate various dampening features and configurations that can be provided with tunable dampeners  708  of earcup assembly  701  in accordance with embodiments of the present disclosure. For example,  FIGS. 8A-8B  illustrate dampeners  808  with a plurality of holes or cavities  820  drilled, cut, or otherwise machined into or through housing plate  807 . In other embodiments, cavities  820  are formed in a driver module frame instead of or in addition to housing plate  807 . A back plate  822  or other layer extends along a back side of housing plate  807  to seal a first end of cavities  820 . A layer of sound absorbing material  806  extends along a front side of housing plate  807  and a second end of cavities  820 . While illustrated without a sound absorbing material  806  within cavities  820 , in other embodiments, such cavities  820  can also be filled with sound absorbing material (e.g., material  806  or a different material). 
     Integrating or forming acoustic dampeners  808  within driver housing plate  807  or in a driver module, effectively increases a path of standing waves reflecting or moving between housing plate and a user&#39;s skull. A path (e.g., identified as P 1 ) extends into and through housing plate  807  such that standing waves reflect off back plate  822  at first end of cavities  820  rather than absorbing material at second end of cavities  820 . As described above with other embodiments, increasing this path and providing a plurality of cavities  820  or chambers provides dampening of standing wave resonances without having to increase a thickness of absorbing material  806  (e.g., allowing a more compact or thin headphone design). However, material  806  extending along a front side of housing plate  807  can provide conventional dampening (e.g., as illustrated by a path P 2  of waves reflected off a front surface of housing plate  807 ), for example, higher frequency resonance. In other embodiments, dampeners  808  do not include a conventional absorbing material  806  extending along front side of housing plate  807 . Further, cavities  820  of dampeners  808  can be configured as acoustic resonators (e.g., a tube with a closed end and open end) and tuned to dampen standing wave resonance(s). Further, cavities  820  can have circular, rectangular, or other suitable cross-sections. 
       FIGS. 9A-9B and 10A-10B  show dampeners  908  and  1008 , respectively. Dampeners  908  and  1008  are configured similarly to dampeners  808  and include one or more identical features, in whole or in part as dampeners  808 . Dampeners  908  and  1008  each include cavities (e.g., cavities  920  and  1020 ) configured or shaped as Helmholtz resonators (e.g., include a neck portion N leading into a cavity portion C). A first end of cavities  920  and  1020  are sealed with back plate  922 ,  1022  or other layer. Additionally, dampeners  908 , include a layer of sound absorbing material  906  (e.g., to provide conventional dampening) extending along a front side of housing plate  907  and a second end of cavities  920 . 
     In contrast to dampeners  908 , dampeners  1008  do not include a layer of sound absorbing material extending along a front side of housing plate  1007  and a second end of cavities  1020 . As described above with respect to cavities  820 , cavities  920  and  1020  can also include absorbing material (e.g., absorbing material  906  or a different type of absorbing material) within each cavity accordingly. Dampeners  908  and  1008  can have resonance frequencies tuned (e.g., according to equation 2) to dampen standing wave resonances. As described above with respect to other embodiments, dampeners  908  and  1008  can be tuned to dampen a single resonance frequency or various different frequencies. 
     As illustrated in  FIGS. 11A-11B  and described above, each of the embodiments of dampeners  1108  (e.g.,  308  and  708 ) can be positioned on a front surface  1110  of driver housing plate  1107  (e.g., as a dampeners on top of the front housing plate or integrated into the housing plate). In some embodiments, tunable dampeners  1108  are positioned on or integrated into a portion of a driver module  1124  in addition to or instead of drive housing plate  1107 . Further, in each of the embodiments of tunable dampeners discussed above, the dampeners can be arranged in an array or matrix-like pattern around a periphery of the speaker  1105  as illustrated. 
     From the foregoing, it will be appreciated that specific embodiments of the invention have been described herein for purposes of illustration, but that various modifications may be made without deviating from the spirit and scope of the various embodiments of the invention. Further, while various advantages associated with certain embodiments of the invention have been described above in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the invention. Accordingly, the invention is not limited, except as by the appended claims. 
     References throughout the foregoing description to features, advantages, or similar language do not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment. 
     Furthermore, the described features, advantages, and characteristics of the present invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the present invention can be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the present invention. 
     Where the context permits, words in the above Detailed Description using the singular or plural number may also include the plural or singular number respectively. The word “or,” in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.

Metadata:
Filing Date: 20180910
Publication Date: 20191105
Grant Date: 20191105
Priority Date: 20170929
Inventors: TIKANDER, MIIKKA O.
WRIGHT, TIMON A.
ANDERSEN, ESGE B.
Assignee: APPLE INC
CPC Classifications: [{"code": "H04R1/2888", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/288", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1008", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R5/0335", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/288", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2888", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2811", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/1008", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R5/0335", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/288", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04R1/2811", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04R1/2888", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 68392187