Balanced stereo headphone with non-balanced air chamber

Abstract

Speaker performance can be improved by increasing the effective acoustic volume, which can be increased by fluidly connecting the speaker chamber, including the speaker, with the mechanical housing. In addition, left and right speaker performance can be balanced. This balancing can be achieved by equalizing the left and right speakers, by adjusting the size of the openings between the speaker chamber and the mechanical housing to balance the acoustic impedance, and / or by using ballast or acoustic diffusing material to increase or decrease the effective acoustic volume of one of the speakers to balance the acoustic volume within the speakers.

Description

TECHNICAL FIELD

[0001] The present application relates generally to headsets, and more specifically, for example, to headsets with enclosures that use a mechanical housing as part of the acoustic chamber and use balancing techniques for headsets with free volumes of different sizes within the mechanical housing. BACKGROUND

[0002] The acoustic performance of a headset depends on the speaker and the acoustic chamber volume. For the same quality of speaker, the larger the acoustic chamber volume, the better the low frequency response that can be achieved. Improved low frequency response results in better audio playback quality and ANC performance. Typically, for stereo headsets, the left and right speakers have different sized and shaped internal cavities due to mechanical design and packaging requirements. However, in order to maintain the same acoustic characteristics of the left and right speakers, the left and right acoustic chamber volumes are kept the same despite the differences in available internal volume between the left and right headsets. SUMMARY

[0003] The present disclosure provides systems and methods that improve the performance of a headset and balance the performance between pairs of headsets.

[0004] In various embodiments, a speaker can be provided. The speaker can include an internal partition wall, a speaker chamber in which at least a portion of the speaker chamber is defined by the internal partition wall, a speaker disposed within the speaker chamber, a mechanical housing in which at least a portion of the mechanical housing is also defined by the internal partition wall, and an opening on the internal partition wall that fluidly connects the speaker chamber with the mechanical housing.

[0005] In various other embodiments, a speaker system can be provided. The speaker system can include a first headset and a second headset. The first headset can include a first internal partition, a first speaker chamber having a first chamber volume and being at least partially defined by the first internal partition, a first speaker disposed within the first speaker chamber, a first mechanical enclosure including a first free volume (wherein at least a portion of the first mechanical enclosure is also defined by the first internal partition), and a first opening on the first internal partition and fluidically connecting the first speaker chamber with the first mechanical enclosure, wherein a first acoustic volume of the first headset includes the first chamber volume and the first free volume inside the first mechanical enclosure. The second headset can include a second internal partition, a second speaker chamber including a second chamber volume and being at least partially defined by the second internal partition, a second speaker disposed within the second speaker chamber, a second mechanical enclosure including a second free volume (wherein at least a portion of the second mechanical enclosure is also defined by the second internal partition), and a second opening on the second internal partition and fluidically connecting the second speaker chamber with the second mechanical enclosure, wherein a second acoustic volume of the second headset includes the second chamber volume and the second free volume inside the second mechanical enclosure.

[0006] In certain embodiments, the first free volume in the first mechanical enclosure and the second free volume in the second mechanical enclosure are the same volume. In certain embodiments, the first headset further includes a component within the first mechanical enclosure, and the second headset further includes a different component disposed within the second mechanical enclosure, such that the first free volume in the first mechanical enclosure is different from the second free volume in the second mechanical enclosure.

[0007] In various embodiments, the speaker can be an on-ear headset or an over-ear headset.

[0008] In certain embodiments, the speaker can further include speaker electronics disposed within the mechanical enclosure. In certain such embodiments, the speaker system can further include a controller communicatively coupled to the first speaker and the second speaker, and the controller is configured to provide first operating instructions to the first speaker and second operating instructions to the second speaker. In certain such embodiments, the first operating instructions are different from the second operating instructions to substantially equalize outputs of the first speaker and the second speaker.

[0009] In certain additional embodiments, the first opening fluidically connecting the first speaker chamber with the first free volume in the first mechanical enclosure and the second opening fluidically connecting the second speaker chamber with the second free volume in the second mechanical enclosure have different sizes and shapes. In certain such embodiments, the first opening and the second opening are designed to substantially equalize acoustic impedances behind the first speaker and the second speaker.

[0010] In certain embodiments, the loudspeaker can further include acoustic diffusing material disposed within the mechanical enclosure. In certain such embodiments, the acoustic diffusing material can be disposed within the first mechanical enclosure or the second mechanical enclosure. In certain such embodiments, the acoustic diffusing material substantially equalizes the acoustic volume of the first free volume and the second free volume.

[0011] In certain embodiments, the loudspeaker can further include ballast disposed within the mechanical enclosure. In certain such embodiments, the ballast material can be disposed within the first mechanical enclosure or the second mechanical enclosure. In certain such embodiments, the ballast substantially equalizes the acoustic volume of the first free volume and the second free volume.

[0012] In various other embodiments, a method is provided. The method can include determining a first acoustic volume of a first mechanical enclosure of a first headset, wherein the first headset further includes a first speaker chamber separated from the first mechanical enclosure by a first interior partition wall, and wherein a first opening is located on the first interior partition wall to fluidly connect the first speaker chamber with the first mechanical enclosure, determining a second acoustic volume of a second mechanical enclosure of a second headset, wherein the second acoustic volume is different than the first acoustic volume, wherein the second headset further includes a second speaker chamber separated from the second mechanical enclosure by a second interior partition wall, and wherein a second opening is located on the second interior partition wall to fluidly connect the second speaker chamber with the second mechanical enclosure, and equalizing output of the first speaker and the second speaker based on the first acoustic volume and the second acoustic volume.

[0013] The scope of the disclosure is defined by the claims, which are incorporated in this section by reference. A more complete understanding of embodiments of the present disclosure, as well as additional features and advantages thereof, will be provided by BRIEF DESCRIPTION OF DRAWINGS

[0014] Aspects of the present disclosure, and their attendant advantages, will be more fully understood by reference to the following drawing and ensuing detailed description. The included drawing is for illustrative purposes only and is merely provided to provide examples of possible systems and methods for the disclosed methods and systems. The drawing is in no way limiting as to any form or detail of the disclosed subject matter that can be made by those skilled in the art without departing from the spirit and scope of the present disclosure.

[0015] Figure 1 A stereo headset is shown in accordance with one or more embodiments of the present disclosure.

[0016] Figure 2 A stereo headset is shown in accordance with one or more embodiments of the present disclosure.

[0017] Figure 3 A cross-sectional view of a headset is shown in accordance with one or more embodiments of the disclosure.

[0018] Figure 4A A cross-sectional view of a headset with balanced left and right performance is shown in accordance with one or more embodiments of the disclosure.

[0019] Figure 4B A schematic diagram showing a representation of a stereo headset is shown in accordance with one or more embodiments of the disclosure.

[0020] Figure 5 A cross-sectional view of another headset with balanced left and right performance is shown in accordance with one or more embodiments of the disclosure.

[0021] Figure 6 A cross-sectional view of yet another headset with balanced left and right performance is shown in accordance with one or more embodiments of the disclosure.

[0022] Figure 7 A block diagram showing a headset with balanced left and right performance is shown in accordance with one or more embodiments of the disclosure.

[0023] Figure 8 A flow diagram showing an example of tuning left and right headsets is shown in accordance with one or more embodiments of the disclosure.

[0024] Figure 9 A plot showing performance differences after tuning left and right headsets is shown in accordance with one or more embodiments of the disclosure. DETAILED DESCRIPTION

[0025] Systems and techniques are described herein for improving the acoustic performance of a speaker. In one embodiment, the frequency response of a headset can be improved by increasing the effective acoustic chamber volume. For example, such a speaker can include an external package that includes a speaker chamber and a mechanical housing. The speaker chamber can include a speaker disposed within the speaker chamber. The mechanical housing can include various other hardware of the headset.

[0026] While left and right speakers of a stereo headset often appear to be symmetrical on the outside, the internal cavities of the left and right speakers are often of different sizes and shapes for the purposes of various acoustic and mechanical functions. Thus, for example, different mechanical components are disposed within the mechanical housings of the left and right speakers. As such, the mechanical housings of the left and right speakers often have different free air volumes (i.e., volumes not occupied by components).

[0027] To maintain similar acoustic properties between the left and right speakers, the left and right speakers typically only use the speaker chamber as the acoustic chamber. Thus, in such speakers, the speaker chamber and the mechanical housing are separated by an internal partition wall. Accordingly, air can not flow between the speaker chamber and the mechanical housing, and thus the speaker chamber and the mechanical housing are not fluidly connected.

[0028] In various embodiments of the speakers described herein, an opening can be located on the internal partition wall to fluidly connect the speaker chamber with the mechanical housing. As such, the effective acoustic chamber volume of such speakers can be increased. In certain embodiments, the effective acoustic chamber volume of both the left and right speakers of a headphone can be increased in this manner. Thus, low frequency performance can be improved.

[0029] However, since the free volume of the mechanical housing of the left and right speakers can be different, various embodiments of the described speakers include structures and / or techniques to maintain balanced acoustic performance between the left and right speakers of a headphone. Thus, various embodiments described herein minimize the loss of useful acoustic volume within the speakers while achieving improved and balanced acoustic performance from a headphone. Speaker performance can be improved while maintaining similar external dimensions or even smaller external dimensions. Furthermore, more affordable speakers or speaker drivers can be used to maintain or improve speaker performance.

[0030] Figure 1 A stereo headphone is shown in accordance with one or more embodiments of the disclosure. Although Figure 1 Embodiments of a stereo headphone are described in accordance with embodiments of the present disclosure, it can be appreciated that the systems and techniques described herein can be applicable to any type of speaker (e.g., external speakers, microphones, car speakers, earbuds, and other speakers).

[0031] Figure 1 A headphone system 100 is shown that includes headphones 102A and 102B and a headband 104. The headphones 102A and 102B can be on-ear or over-ear headphones configured to be disposed over the ears of a wearer. The headband 104 can couple the headphone 102A to the headphone 102B. Certain embodiments of the headband 104 can be configured to rest on top of the head of a wearer.

[0032] The headphone 102A can be a left headphone and the headphone 102B can be a right headphone. The headphones 102A and 102B can form a stereo speaker system. For a stereo speaker system, output balance between the various speakers is important. In various other embodiments, such speakers can be any type of speaker (e.g., dynamic speakers, balanced armature speakers, piezoelectric speakers, etc.).

[0033] Figure 2 A cross-sectional view of a stereo headset is shown in accordance with one or more embodiments of the disclosure. Figure 2 A cross-sectional view of a stereo headset system 100 is shown, including headsets 102A and 102B and headband 104. Headsets 102A and 102B can each include the external packaging shown. Figure 1 A cross-sectional view of a stereo headset system 100 is shown, including headsets 102A and 102B and headband 104. Headsets 102A and 102B can each include the external packaging shown. Figure 2 A cross-sectional view of a stereo headset system 100 is shown, including headsets 102A and 102B and headband 104. Headsets 102A and 102B can each include the external packaging shown.

[0034] Headset 102A includes speaker chamber 206A and mechanical housing 208A. Speaker chamber 206A can be a first chamber volume. Speaker 210A is disposed within speaker chamber 206A and behind ear pad 218A. Ear pad 218A can be a soft cushion configured to contact a wearer's ear and increase wearer comfort while allowing sound waves produced by speaker 210A to pass through the wearer's ear.

[0035] Mechanical housing 208A can include one or more electronic or mechanical components, such as battery 216A. Speaker chamber 206A is separated from mechanical housing 208A by interior partition wall 212A. Interior partition wall 212A can define a "behind" (e.g., relative to the direction of sound waves output from speaker 210A) portion of speaker chamber 206A and a "front" portion of mechanical housing 208A. Thus, mechanical housing 208A can be "behind" speaker chamber 206A and separated from speaker chamber 206A by interior partition wall 212A.

[0036] Opening 214A can be disposed on interior partition wall 212A to fluidly connect speaker chamber 206A with mechanical housing 208A. Thus, air can pass between speaker chamber 206A and mechanical housing 208A, increasing the effective acoustic chamber volume of headset 102A.

[0037] Headset 102B includes similar components as described for headset 102A. Headset 102B can include a second chamber volume, speaker chamber 206B. In various embodiments, the first and second chamber volumes can be the same volume (e.g., to equalize the left and right acoustic characteristics of headset system 100). One or more electronic or mechanical components, such as printed circuit board (PCB) 216B, can be disposed in mechanical housing 208B of headset 102B. PCB 216B can be a controller configured to control the operation of headset system 100. Accordingly, mechanical housings 208A and 208B include different components that serve different purposes. For example, battery 216A can be different in volume than PCB 216B. Accordingly, the free volume of mechanical housings 208A and 208B can be different. As such, although the effective acoustic chamber volume of both headsets 102A and 102B is increased by fluidly connecting speaker chambers 206A and 206B with mechanical housings 208A and 208B, respectively, the effective acoustic chamber volume of headsets 102A and 102B can be different. Accordingly, simply transforming mechanical housings 208A and 208B into back acoustic chambers by fluidly coupling mechanical housings 208A and 208B with speaker chambers 206A and 206B, respectively, can result in unbalanced acoustic performance between headsets 102A and 102B due to the difference in effective acoustic chamber volume.

[0038] Figure 3 A cross-sectional view of a headset is shown in accordance with one or more embodiments of the disclosure. Figure 3 A further detailed view of headset 302 of a headset system is shown. Headset 302 includes speaker chamber 306, mechanical housing 308, speaker 310, internal partition wall 312 with opening 314, and component 316. As shown, opening 314 in internal partition wall 312 allows speaker chamber 306 and mechanical housing 308 to be fluidly connected, increasing the effective acoustic chamber volume.

[0039] Figure 4A A cross-sectional view of a headset with equalized left and right performance is shown in accordance with one or more embodiments of the disclosure. As described herein, in certain embodiments, the effective acoustic chamber volume of left and right headsets 402A and 402B can be different. Figure 4A Techniques to tune the performance of headsets 402A and 402B are shown.

[0040] In Figure 4AIn particular, left and right headphones 402A and 402B include different sized openings 414A and 414B (e.g., 414A and 414B can be circular interfaces of different diameters and lengths, or other geometric differences such as different shapes) to connect the respective speaker chambers 406A and 406B with the corresponding mechanical enclosures 408A and 408B. Despite the different free volumes of mechanical enclosures 408A and 408B, the different openings 414A and 414B are sized such that the same or substantially the same (e.g., within 20%) acoustic impedance is seen behind left and right speakers 410A and 410B, respectively.

[0041] Tuning to match acoustic impedance is further illustrated in Figure 4B . Figure 4B A schematic diagram illustrating an acoustic representation of a stereo headphone in accordance with one or more embodiments of the present disclosure is shown. Figure 4B is Figure 4A An acoustic circuit representation of the configuration shown in Figure 4A . For the configuration of Figure 9 , the acoustical compliance of left and right speaker chambers 406A and 406B is the same (assuming left and right speaker chambers 406A and 406B are the same size), the acoustical inductance of left and right openings 414A and 414B is different, and the acoustical compliance of mechanical enclosures 408A and 408B is different due to the different free volumes within mechanical enclosures 408A and 408B. Adjusting the size and other geometric parameters of openings 414A and 414B allows for adjusting the acoustical inductance of each of headphones 402A and 402B. When tuned to the different acoustical compliances of mechanical enclosures 408A and 408B, the same or substantially the same acoustic impedance is seen behind speakers 410A and 410B when using different sized openings 414A and 414B, resulting in balanced performance. Such balanced performance is further described in Figure 9 .

[0042] Figure 5 A cross-sectional view of another headphone with balanced left and right performance in accordance with one or more embodiments of the present disclosure is shown. In Figure 5 , due to the larger volume of space occupied by the components within mechanical enclosure 508A, the free volume within mechanical enclosure 508A can initially be less than the free volume of mechanical enclosure 508B. To balance or substantially balance the free volumes of mechanical enclosures 508A and 508B, ballast 520B is added to mechanical enclosure 508B to balance the performance of headphones 502A and 502B. Ballast 520B can be any component that reduces the free volume of mechanical enclosure 508B. In certain embodiments, ballast 520B can help Figure 5The ballast 520B can function to equalize the free volumes of the headsets 502A and 502B and / or act as a weight ballast in some embodiments, but in other embodiments the ballast 520B can only function to equalize the free volumes of the headsets 502A and 502B.

[0043] Figure 6 A cross-sectional view of yet another headset with equalized left and right performance is shown in accordance with one or more embodiments of the disclosure. In Figure 6 In some embodiments, the free volume within the mechanical housing 608A can initially be less than the free volume within the mechanical housing 608B. Acoustic diffusing material 622 is added to the mechanical housing 608A. The acoustic diffusing material 622 effectively increases the acoustic volume of the mechanical housing 608A. Adding such acoustic diffusing material 622 can increase the effective acoustic volume of the mechanical housing 608A to be the same or substantially the same as the mechanical housing 608B.

[0044] Figure 7 A block diagram of a headset with equalized left and right performance is shown in accordance with one or more embodiments of the disclosure. Figure 7 Headsets 702A and 702B are shown with speakers 710A and 710B, respectively. The effective acoustic volume 709A of the headset 702A can be less than the effective acoustic volume 709B of the headset 702B.

[0045] A controller 730 can be communicatively connected (e.g., provide instructions) to the speakers 710A and 710B and control the operation of the speakers 710A and 710B. In certain embodiments, the controller 730 can include a processor, which can include a central processing unit, a microcontroller, a digital signal processor (DSP), or other processing component for controlling and facilitating the operation of the speakers 710A and 710B. In some embodiments, the controller 730 can further include an analog-to-digital converter that converts analog audio signals to digital audio signals (and vice versa) and communicates the signals to the speakers 710A and 710B.

[0046] The controller 730 can include one or more communication channels such as buses for facilitating data communication. The controller 730 can additionally include devices for providing device operation and functionality, such as input / output components (e.g., touchscreens, buttons, external data connections, and other components), memory such as RAM, solid state drives, disk drives, databases, etc., and communication interfaces. In some embodiments, the communication interfaces can include network interfaces or wireless transceivers for enabling communication with other devices via a network or other wireless connection.

[0047] To equalize the performance of the headphones 702A and 702B, the controller 730 can provide different equalization signals (EQs) to the speakers 710A and 710B. Such different EQs can be provided according to the different effective acoustic volumes 709A and 709B. The different EQs can result from, for example, placing analog filters within the drivers of one or both of the speakers 710A and 710B or by different software or hardware implementations of a digital speaker. Accordingly, such digital speakers can include software that emulates the software of an analog filter to equalize the EQs of the speakers 710A and 710B. The EQs can equalize or substantially equalize the left / right speaker performance of the headphones 702A and 702B.

[0048] Figure 8 is a flowchart illustrating an example of tuning left and right headphones in accordance with one or more embodiments of the disclosure. In block 802, an effective acoustic volume of a first free volume or a first headphone (e.g., a left headphone) is determined. In block 804, an effective acoustic volume of a second free volume or a second headphone (e.g., a right headphone) is determined.

[0049] Once the effective acoustic volumes of the headphones are determined in blocks 802 and 804, the output of the headphones is equalized or substantially equalized in block 806. Accordingly, in block 806, a controller of the headphone system can be configured to equalize the output of the headphones based on the different effective acoustic volumes, different sized openings can be employed within the headphones, the free volume of the mechanical housing can be equalized, and / or the acoustic volume of the headphones can be equalized. As such, the acoustic performance of the stereo headphones can be equalized.

[0050] Figure 9 is a graph illustrating the difference in performance after tuning left and right headphones in accordance with one or more embodiments of the disclosure. Figure 9 An example is shown when the acoustic performance is equalized between headphones. Although Figure 9 The example shown in is a result of tuning the EQs of the speakers to equalize the performance of the headphones, similar to Figure 9 The results of can be achieved by any other techniques described herein. Figure 9 is shown the output of a speaker at various frequencies.

[0051] Figure 9 is shown the performance of four different versions of headphones. The "speaker only cavity" headphones are headphones in which only the speaker chamber is used as the acoustic chamber. As shown, such a configuration results in poor low frequency performance.

[0052] "Left" and "right" headphones are headphones where the mechanical housing also serves as part of the sound chamber. Although the low frequency performance of both the "left" and "right" headphones is improved, the "right" headphone includes a much smaller free volume within the mechanical housing, and thus the performance of the headphone does not match.

[0053] "EQ after" headphones are a headphone system where the left and right EQs are tuned to equalize performance between the headphones. As shown, after EQ tuning, the left and right outputs are tuned to be the same while the low frequency response is superior to headphones where only the speaker chamber serves as the sound chamber. Thus, improved and equalized low frequency performance can be achieved between both the left and right headphones.

[0054] Where applicable, various embodiments provided by the present disclosure can be implemented using hardware, software, or combinations of hardware and software. In addition, where applicable, the various hardware components and / or software components set forth herein can be combined into composite components including software, hardware, and / or both without departing from the spirit of the present disclosure. Where applicable, the various hardware components and / or software components set forth herein can be separated into sub-components

[0055] Software, such as program code and / or data, according to the present disclosure, can be stored on one or more computer-readable media. It is also contemplated that software identified herein can be implemented using one or more general purpose or special purpose computers and / or computer systems, network and / or other ocumentation. Where applicable, the order of the various steps described herein can be changed, combined into composite steps, and / or separated into sub-steps to provide features described herein.

[0056] The foregoing disclosure is not intended to be exhaustive or to limit the present disclosure to the precise forms disclosed. As such, various alternative embodiments and / or modifications to the present disclosure, whether explicitly described or implied herein, are potentially available. Having described aspects of the disclosure in detail, it will be apparent to those skilled in the art that modifications can be made of the description herein without departing from the scope of the disclosure and the general nature thereof. Therefore, the disclosure should not be limited, except to the full extent permitted by the law.

Claims

1. A speaker system comprising: a first speaker and a second speaker, each comprising: an internal partition wall; a speaker chamber, wherein at least a portion of the speaker chamber is defined by the internal partition wall; a speaker disposed within the speaker chamber; a mechanical enclosure, wherein at least a portion of the mechanical enclosure is also defined by the internal partition wall; and an opening on the internal partition wall and fluidically connecting the speaker chamber with the mechanical enclosure; wherein the mechanical enclosure of the first speaker has a first free volume and the mechanical enclosure of the second speaker has a second free volume different from the first free volume; and a controller configured to equalize an output of the speaker system from the mechanical enclosure of the first speaker with an output of the speaker system from the mechanical enclosure of the second speaker.

2. The speaker system of claim 1, further comprising speaker electronics disposed within the mechanical enclosure.

3. The speaker system of claim 1, further comprising acoustic diffusing material disposed within the mechanical enclosure.

4. The speaker system of claim 1, further comprising ballast disposed within the mechanical enclosure.

5. The speaker system of claim 1, wherein the speaker system is a on-ear or over-ear headphone.

6. A speaker system comprising: a first headphone comprising: a first internal partition wall; a first speaker chamber comprising a first chamber volume and at least partially defined by the first internal partition wall; a first speaker disposed within the first speaker chamber; a first mechanical enclosure comprising a first free volume, wherein at least a portion of the first mechanical enclosure is also defined by the first internal partition wall; and a first opening on the first internal partition wall and fluidically connecting the first speaker chamber with the first mechanical enclosure, wherein a first effective acoustic volume of the first headphone comprises the first free volume and the first chamber volume; and a second headphone comprising: a second internal partition wall; a second speaker chamber comprising a second chamber volume and at least partially defined by the second internal partition wall; a second speaker disposed within the second speaker chamber; a second mechanical enclosure comprising a second free volume, wherein at least a portion of the second mechanical enclosure is also defined by the second internal partition wall; and a second opening on the second internal partition wall and fluidically connecting the second speaker chamber with the second mechanical enclosure, wherein a second effective acoustic volume of the second headphone comprises the second free volume and the second chamber volume, wherein the first free volume of the first mechanical enclosure is different from the second free volume of the second mechanical enclosure; and a controller communicatively coupled to the first speaker and the second speaker and configured to provide first operating instructions to the first speaker and second operating instructions to the second speaker, wherein the first operating instructions are different than the second operating instructions to substantially equalize output of the first speaker and the second speaker.

7. The speaker system of claim 6, wherein the first headset further comprises a first assembly disposed within the first mechanical housing, and wherein the second headset further comprises a second assembly disposed within the second mechanical housing.

8. The speaker system of claim 6, wherein the first effective acoustic volume and the second effective acoustic volume are different volumes.

9. The speaker system of claim 8, wherein the first opening and the second opening are different sizes that are sized to substantially equalize acoustic impedance behind the first speaker and the second speaker.

10. A method comprising: determining a first free volume of a first mechanical housing of a first headset, wherein the first headset further comprises a first speaker chamber separated from the first mechanical housing by a first internal partition wall, and wherein a first opening is located on the first internal partition wall to fluidly connect the first speaker chamber with the first mechanical housing; determining a second free volume of a second mechanical housing of a second headset, wherein the second free volume is different than the first free volume, wherein the second headset further comprises a second speaker chamber separated from the second mechanical housing by a second internal partition wall, and wherein a second opening is located on the second internal partition wall to fluidly connect the second speaker chamber with the second mechanical housing; and equalizing output of the first speaker and the second speaker based on the first free volume and the second free volume.

11. The method of claim 10, wherein equalizing the output comprises: configuring a controller to provide first operating instructions to the first speaker and second operating instructions to the second speaker, wherein the first operating instructions are different than the second operating instructions to substantially equalize output of the first speaker and the second speaker.

12. The method of claim 10, wherein equalizing the output comprises sizing the first opening and the second opening to substantially equalize acoustic impedance behind the first speaker and the second speaker.

13. The method of claim 10, wherein equalizing the output comprises disposing ballast within a larger of the first mechanical housing and the second mechanical housing to substantially equalize the first free volume and the second free volume.

14. The method of claim 10, wherein equalizing the output comprises disposing acoustic diffusing material within a smaller of the first mechanical housing and the second mechanical housing to substantially equalize acoustic volumes of the first free volume and the second free volume.

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