EP3351012B1

EP3351012B1 - Acoustic device

Info

Publication number: EP3351012B1
Application number: EP16775038.9A
Authority: EP
Inventors: Roman N. Litovsky; Bojan Rip; Joseph M. Geiger; Chester Smith Williams; Pelham Norville
Original assignee: Bose Corp
Current assignee: Bose Corp
Priority date: 2015-09-17
Filing date: 2016-09-15
Publication date: 2020-07-15
Anticipated expiration: 2036-09-15
Also published as: EP3351012A1; CN108353224B; JP2018534815A; JP6594530B2; WO2017048943A1; CN108353224A

Description

BACKGROUND

This disclosure relates to an acoustic device.
Headsets have acoustic drivers that sit on, over or in the ear. They are thus somewhat obtrusive to wear, and can inhibit the user's ability to hear ambient sounds. An acoustic device in the form of a neck loop, incorporating acoustic drivers are known from US 2014/126760 A1 , WO 95/34184 A1 , and GB 2 517 486 A , for example. US4084139A shows an acoustic device worn around the neck of a user with a foam member as a retention member.

SUMMARY

The present invention provides an acoustic device according to claim 1. Further embodiments are defined in the dependent claims. All examples and features mentioned below can be combined in any technically possible way.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is top perspective view of an acoustic device.
Fig. 2 is top perspective view of the acoustic device being worn by a user.
Fig. 3 is a right side view of the acoustic device.
Fig. 4 is front view of the acoustic device.
Fig. 5 is a rear view of the acoustic device.
Fig. 6 is top perspective view of the interior septum or wall of the housing of the acoustic device.
Fig. 7 is a first cross-sectional view of the acoustic device taken along line 7-7 in figure 1.
Fig. 8 is a second cross-sectional view of the acoustic device taken along line 8-8 in figure 1.
Fig. 9 is a third cross-sectional view of the acoustic device taken along line 9-9 in figure 1.
Fig. 10 is a schematic block diagram of the electronics for an acoustic device.
Fig. 11 is a plot of the sound pressure level at an ear of a dummy head, with the drivers of the acoustic device driven both in phase and out of phase.
Figs. 12A-12C is a top perspective view of an acoustic device which includes various stabilizing elements being worn by a user.

DETAILED DESCRIPTION

The acoustic device directs high quality sound to the ears without direct contact with the ears, and without blocking ambient sounds. The acoustic device is unobtrusive, and can be worn under (if the clothing is sufficiently acoustically transparent) or on top of clothing.
In one aspect, the acoustic device is constructed and arranged to be worn around the neck. The acoustic device has a neck loop that includes a housing. The neck loop has a horseshoe-like shape, with two legs that sit over the top of the torso on either side of the neck, and a curved central portion that sits behind the neck. The device has two acoustic drivers one on each leg of the housing. The drivers are located below the expected locations of the ears of the user, with their acoustic axes pointed at the ears. The acoustic device also has two waveguides within the housing, each one having an exit below an ear, close to a driver. The rear side of one driver is acoustically coupled to the entrance to one waveguide and the rear side of the other driver is acoustically coupled to the entrance to the other waveguide. Each waveguide has one end with the driver that feeds it located below one ear (left or right), and the other end (the open end) located below the other ear (right or left), respectively.
A non-limiting example of the acoustic device is shown in the drawings. This is but one of many possible examples that would illustrate the subject acoustic device. The scope of the invention is not limited by the example but rather is supported by the example.
Acoustic device 10 (figures 1-9) includes a horseshoe-shaped (or, perhaps, generally "U"-shaped) neck loop 12 that is shaped, constructed and arranged such that it can be worn around the neck of a person, for example as shown in figure 2. Neck loop 12 has a curved central portion 24 that will sit at the nape of the neck "N", and right and left legs 20 and 22, respectively, that depend from central portion 24 and are constructed and arranged to drape over the upper torso on either side of the neck, generally over or near the clavicle "C." Figures 3-5 illustrate the overall form that helps acoustic device 10 to drape over and sit comfortably on the neck and upper chest areas.
Neck loop 12 comprises housing 13 that is in essence an elongated (solid or flexible) mostly hollow solid plastic tube (except for the sound inlet and outlet openings), with closed distal ends 27 and 28. In some examples, the housing 13 is divided internally by integral wall (septum) 102. In one non-limiting example, two internal waveguides are defined by the external walls of the housing and the septum 102. Housing 13 should be stiff enough such that the sound is not substantially degraded as it travels through the waveguides. In the present non-limiting example, where the lateral distance "D" between the ends 27 and 28 of right and left neck loop legs 20 and 22 is less than the width of a typical human neck, the neck loop also needs to be sufficiently flexible such that ends 27 and 28 can be spread apart when device 10 is donned and doffed, yet will return to its resting shape shown in the drawings. One of many possible materials that has suitable physical properties is polyurethane. Other materials could be used. Also, the device could be constructed in other manners. For example, the device housing could be made of multiple separate portions that were coupled together, for example using fasteners and/or adhesives. And, the neck loop legs do not need to be arranged such that they need to be spread apart when the device is placed behind the neck with the legs draped over the upper chest.
Housing 13 carries right and left acoustic drivers 14 and 16. The drivers are located at the top surface 30 of housing 13, and below the expected location of the ears "E." See figure 2. Housing 13 has lower surface 31. The drivers may be canted or angled backwards (posteriorly) as shown, as may be needed to orient the acoustic axes of the drivers (not shown in the drawings) generally at the expected locations of the ears of the wearer/user. The drivers may have their acoustic axes pointed at the expected locations of the ears. Each driver may be about 10 cm from the expected location of the nearest ear, and about 26 cm from the expected location of the other ear (this distance measured with a flexible tape running under the chin up to the most distant ear). The lateral distance between the drivers is about 15.5 cm. This arrangement results in a sound pressure level (SPL) from a driver about three times greater at the closer ear than the other ear, which helps to maintain channel separation.
Located close to and just posteriorly of the drivers and in the top exterior wall 30 of housing 13 are waveguide outlets 40 and 50. Outlet 50 is the outlet for waveguide 110 which has its entrance at the back of right-side driver 14. Outlet 40 is the outlet for waveguide 160 which has its entrance at the back of left-side driver 16. See figures 7-9. Accordingly, each ear directly receives output from the front of one driver and output from the back of the other driver. If the drivers are driven out of phase, the two acoustic signals received by each ear are virtually in phase below the fundamental waveguide quarter wave resonance frequency, that in the present non-limiting example is about 130-360 Hz. This ensures that low frequency radiation from each driver and the same side corresponding waveguide outlet, are in phase and do not cancel each other. At the same time the radiation from opposite side drivers and corresponding waveguides are out of phase, thus providing far field cancellation. This reduces sound spillage from the acoustic device to others who are nearby.
Acoustic device 10 includes right and left button socks or partial housing covers 60 and 62; button socks are sleeves that can define or support aspects of the device's user interface, such as volume buttons 68, power button 74, control button 76, and openings 72 that expose the microphone. When present, the microphone allows the device to be used to conduct phone calls (like a headset). Other buttons, sliders and similar controls can be included as desired. The user interface may be configured and positioned to permit ease of operation by the user. Individual buttons may be uniquely shaped and positioned to permit identification without viewing the buttons. Electronics covers are located below the button socks. Printed circuit boards that carry the hardware that is necessary for the functionality of acoustic device 10, and a battery, are located below the covers.
Housing 13 includes two waveguides, 110 and 160. See figures 7-9. Sound enters each waveguide just behind/underneath a driver, runs down the top side of the neck loop leg on which the driver is located to the end of the leg, turns 180° and down to the bottom side of the housing at the end of the leg, and then runs back up the leg along the bottom side of the housing. The waveguide continues along the bottom side of the first part of the central portion of the neck loop. The waveguide then twists such that at or close to the end of the central portion of the neck loop it is back in the top side of the housing. The waveguide ends at an outlet opening located in the top of the other leg of the neck loop, close to the other driver. The waveguides are formed by the space between the outer wall of the housing and internal integral septum or wall 102. Septum 102 (shown in figure 6 apart from the housing) is generally a flat integral internal housing wall that has right leg 130, left leg 138, right end 118, left end 140, and central 180° twist 134. Septum 102 also has curved angled diverters 132 and 136 that direct sound from a waveguide that is running about parallel to the housing axis, up through an outlet opening that is in the top wall of the housing above the diverter, such that the sound is directed generally toward one ear.
The first part of waveguide 110 is shown in figure 7. Waveguide entrance 114 is located directly behind the rear 14a of acoustic driver 14, which has a front side 14b that is pointed toward the expected location of the right ear. Downward leg 116 of waveguide 110 is located above septum 102 and below upper wall/top 30 of the housing. Turn 120 is defined between end 118 of septum 102 and closed rounded end 27 of housing 12. Waveguide 110 then continues below septum 102 in upward portion 122 of waveguide 110. Waveguide 110 then runs under diverter 133 that is part of septum 102 (see waveguide portion 124), where it turns to run into central housing portion 24. Figures 8 and 9 illustrate how the two identical waveguides 110 and 160 run along the central portion of the housing and within it fold or flip over each other so that each waveguide begins and ends in the top portion of the housing. This allows each waveguide to be coupled to the rear of one driver in one leg of the neck loop and have its outlet in the top of the housing in the other leg, near the other driver. Figures 8 and 9 also show second end 140 of septum 102, and the arrangement of waveguide 160 which begins behind driver 16, runs down the top of leg 22 where it turns to the bottom of leg 22 and runs up leg 22 into central portion 24. Waveguides 110 and 140 are essentially mirror images of each other.
In one non-limiting example, each waveguide has a generally consistent cross-sectional area along its entire length, including the generally annular outlet opening, of about 2 cm². In one non-limiting example each waveguide has an overall length in the range of about 22-44 cm; very close to 43 cm in one specific example. In one non-limiting example, the waveguides are sufficiently long to establish resonance at about 150 Hz. More generally, the main dimensions of the acoustic device (e.g., waveguide length and cross-sectional area) are dictated primarily by human ergonomics, while proper acoustic response and functionality is ensured by proper audio signal processing. Other waveguide arrangements, shapes, sizes, and lengths are contemplated within the scope of the present disclosure.
An exemplary but non-limiting example of the electronics for the acoustic device are shown in figure 10. In this example the device functions as a wireless headset that can be wirelessly coupled to a smartphone, or a different audio source. PCB 103 carries microphone 164 and mic processing. An antenna receives audio signals (e.g., music) from another device. Bluetooth wireless communication protocol (and/or other wireless protocols) are supported. The user interface can be but need not be carried as portions of both PCB 103 and PCB 104. A system-on-a-chip generates audio signals that are amplified and provided to L and R audio amplifiers on PCB 104. The amplified signals are sent to the left and right transducers (drivers) 16 and 14, which as described above are open-backed acoustic drivers. The acoustic drivers may have a diameter of 40 mm diameter, and a depth of 10 mm, but need not have these dimensions. PCB 104 also carries battery charging circuitry that interfaces with rechargeable battery 106, which supplies all the power for the acoustic device.
Figure 11 illustrates the SPL at one ear with the acoustic device described above. Plot 196 is with the drivers driven out of phase and plot 198 is with the drivers driven in-phase. Below about 150 Hz the out of phase SPL is higher than for in-phase driving. The benefit of out of phase driving is up to 15 dB at the lowest frequencies of 60-70 Hz. The same effect takes place in the frequency range from about 400 to about 950 Hz. In the frequency range 150-400 Hz in-phase SPL is higer than out of phase SPL; in order to obtain the best driver performance in this frequency range the phase difference between left and right channels should be flipped back to zero. In one non-limiting example the phase differences between channels are accomplished using so-called all pass filters having limited phase change slopes. These provide for gradual phase changes rather than abrupt phase changes that may have a detrimental effect on sound reproduction. This allows for the benefits of proper phase selection while assuring power efficiency of the acoustic device. Above 1 KHz, the phase differences between the left and right channels has much less influence on SPL due to the lack of correlation between channels at higher frequencies.
Figures 12A through 12C depict three non-limiting examples of the acoustic device 10 further including a stabilizing element to provide additional support and retention for the user wearing the device. The stabilizing element functions to keep the acoustic device 10 in place for use during rigorous activities such as running, jogging, skiing, mountain biking, and weight training, for example.
As described above with respect to Figures 1-9, the acoustic device10 in Figures 12A through 12C , includes a Neck loop 12 (Figure 1) a curved central portion 24 (Figure 1) that will sit at the nape of the neck "N" (Figure 2), and right and left legs 20 and 22, respectively, that depend from central portion 24 and are constructed and arranged to drape over the upper torso on either side of the neck, generally over or near the clavicle "C" (Figure 2). The acoustic device 10 in Figures 12A through 12C includes one or more drivers (not shown). The drivers may be located on or below the surface of the housing of the acoustic device 10, generally within the right and left legs 20 and 22, respectively, and below the expected location of the ears "E" (Figure 2). As previously described, the drivers may be angled to orient the acoustic axes of the drivers generally at the expected location of the ears of the user. Each driver may be about 10 cm from the expected location of the nearest ear, and about 26 cm from the expected location of the other ear (this distance measured with a flexible tape running under the chin up to the most distant ear). The lateral distance between the drivers is about 15.5 cm. The acoustic device 10 of Figures 12A through 12C may also waveguide outlets (not shown) located close to and just posteriorly of the drivers along the right and left legs 20 and 22, respectively.
Figure 12A shows an acoustic device 10 including a strap 200 attached to the acoustic device 10 and releasable clasp 202 which together provide additional stability by permitting the user to releasably secure the device to the torso for use during rigorous activities. Figure 12B shows an acoustic device 10 including a stabilizing collar 204 which is designed, sized, and configured to contact or at least partially contact the back and sides of the user's neck. The stabilizing collar 204 provides additional stability for using of the acoustic device 10 during the activities described above. Figure 12C shows an acoustic device 10 including an inflatable chamber 206 to impart additional stability for use of the device 10 during the activities described above. The chamber 206 is designed, sized, and configured to contact the back and sides of the user's neck. In this example, the chamber 206 may be inflated with air or other suitable gas to a pressure level that provides sufficient stability and comfort for the user. The pressure level inside the chamber 206 may be adjusted to a level suitable for a particular user or for use during a particular activity. The chamber 206 can include a pressure valve (not shown) to facilitate adding or releasing air as understood by a person of ordinary skill in the art. In one non-limiting example, the chamber 206 can include multiple sub-chambers or segments to impart a predefined shape or direction of pressure against the neck of the user as the chamber is inflated.
The housing of the acoustic device 10 may include a skin or cover which surrounds a portion or all device housing. In one example, the cover includes acoustically transparent regions in those locations where the cover overlays the drivers and/or waveguide outlets in right and left legs 20 and 22, respectively, of the acoustic device 10. In some examples, the cover serves to protect the acoustic device 10 from scratches or abrasion, provide further comfort to the user while wearing the device 10, and/or may allow customization of the appearance of the device 10. The skin may be removable or permanently attached to the acoustic device 10.
A number of implementations have been described. Nevertheless, it will be understood that additional modifications may be made without departing from the scope of the invention as defined by the following claims.

Claims

An acoustic device (10), comprising:
a neck loop (12) that is constructed and arranged to be worn around the neck of a user, the neck loop being generally "U"-shaped with a central portion (24) and first and second leg portions (20;22) that depend from the central portion, the neck loop comprising a housing (13) that comprises a first acoustic waveguide (110) having a first sound outlet opening (50), and a second acoustic waveguide (160) having a second sound outlet opening (40);

a first open-backed acoustic driver (14) located in the first leg portion (20) and acoustically coupled to the first waveguide, where the first open-backed acoustic driver is carried by the housing and has a first sound axis that is pointed generally at the expected location of one ear of the user;

a second open-backed acoustic driver (16) located in the first leg portion (22) and acoustically coupled to the second waveguide, where the second open-backed acoustic driver is carried by the housing and has a second sound axis that is pointed generally at the expected location of the other ear of the user; and

a retention member extending from the housing of the neck loop, the retention member being sized and configured to contact the neck of the user and further stabilize the acoustic device;

wherein the first sound outlet opening is located proximate to the second acoustic driver and the second sound outlet opening is located proximate to the first acoustic driver; and

wherein the first and second acoustic drivers are driven such that they radiate sound that is out of phase.
The acoustic device (10) of claim 1 wherein the waveguides are both defined by an exterior wall of the housing and an interior wall of the housing, and wherein the interior wall of the housing lies along a longitudinal axis that is twisted 180° along its length.
The acoustic device (10) of claim 2 wherein the first and second leg portions have distal ends that are spaced apart to define an open end of the neck loop, wherein the twist in the housing interior wall is located in the central portion of the neck loop.
The acoustic device (10) of claim 3 wherein the housing has a top portion that is closest to the ears when worn by the user and a bottom portion that is closest to the torso when worn by the user, and wherein each waveguide lies in part in the top portion of the housing and in part in the bottom portion of the housing.
The acoustic device (10) of claim 1 wherein the first and second leg portions have distal ends that are spaced apart to define an open end of the neck loop.
The acoustic device (10) of claim 1 wherein each waveguide has one end with its corresponding acoustic driver located at one side of the head and in proximity to and below the adjacent ear, and another end that leads to its sound outlet opening, located at the other side of the head and in proximity to and below the other, adjacent ear.
The acoustic device (10) of claim 1 wherein the housing has an exterior wall, the first sound outlet opening is defined in the exterior wall of the housing, and the second sound outlet opening is defined in the exterior wall of the housing.
The acoustic device (10) of claim 7 wherein the waveguides are both defined by the exterior wall of the housing and an interior wall of the housing.
The acoustic device (10) of claim 7 wherein the housing has a top that faces the ears when worn by the user, and wherein the first sound outlet opening is defined in the top of the housing and the second sound outlet opening is defined in the top of the housing.
The acoustic device (10) of claim 1 wherein the first waveguide and second waveguide are separate and fold over one another within the housing.