US3794779A

US3794779A - Headphones for reproducing four-channel sound

Info

Publication number: US3794779A
Application number: US00173809A
Authority: US
Inventors: C Greuzerd; L Henkin
Original assignee: Individual
Current assignee: Individual
Priority date: 1971-08-23
Filing date: 1971-08-23
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26

Abstract

Each headphone casing encloses forwardly and rearwardly extending, segregated, acoustic mixing chambers segregated by a generally vertical partition and opening inwardly through a common, generally central opening to an ear of the person wearing the headphones. The headphone segregated mixing chambers preferably have specifically contoured walls with a sound emitting device in each mixing chamber directed at least partially against said walls for a proper sound mixing in each mixing chamber and the headphones central openings are of appropriate various sizes and depth for at least fully receiving the persons ear with acoustic integrating chambers of various sizes formed by the central openings adjacent the ears and simultaneously communicating with each of the segregated mixing chambers. Thus, with one channel of four-channel sound directed into each of the mixing chambers of a set of the earphones, the full effect of four-channel sound is received, and by similar connection of stereophonic sound, many of the four-channel sound effects are reproduced from the stereophonic sound.

Description

United States Patent [191 Greuzerd et al. v

[4 1 Feb. 26, 1974 HEADPHONES FOR REPRODUCING FOUR-CHANNEL SOUND [75] inventors: Charles E. Greuzerd, Garden Grove; Louis Lawrence l-lenkin, Huntington Park, both of Calif.

[73] Assignees: Victor B. Morgan, Los Alamitos;

Thomas P. Mahoney; George E. Schick, both of Santa Monica, all of, Calif. part interest to each [22] Filed: Aug. 23, 1971 [21] App]. No.: 173,809

[52] US. Cl. 179/156 R, 179/] GO, 179/182 R [51] Int. Cl. H04m 1/05 [58] Field of Search....'.. 179/1 G, 1 GA, 156 R, 182

Fixler 179/1 G Primary Examiner-William C. Cooper Atto'rney, Agent, or Firm-Mahoney, Schick &'Cislo 57 ABSTRACT Each headphone casing encloses forwardly and rearwardly extending, segregated, acoustic mixing chambers segregated by a generally vertical partition and opening inwardly through a common, generally central opening to an ear of the person wearing the headphones. The headphone segregated mixing chambers preferably have specifically contoured walls with a sound emitting device in each mixing chamber directed at least partially against said walls for a proper sound mixing in each mixing chamber and the head phones central openings are of appropriate various sizes and depth for at least fully receiving the persons ear with acoustic integrating chambers of various sizes formed by the central openings adjacent the ears and simultaneously communicating with each of the segregated mixing chambers. Thus, with one channel of four-channel sound directed into each of the mixing chambers of a set of the earphones, the full effect of four-channel sound is received, and by similar connection of stereophonic sound,.many of the four-channel sound effects are reproduced from the stereophonic sound.

15 Claims, 9 Drawing Figures PATENTEDFEBZB 1974 INVEVNTORS. CHARLES E. GREUZARD By Laws L. HENKIN MAHONEY, HORNBAKER AND SCH/CK ATTORNEYS PATENTEDFEBZG I974 SHEET 2 BF 4 IN VENTORS.

CHARLES E. GREuzARo BY Lou/s L. HENKIN HONEY, HORNBA KER AND SCH/CK ATTORNEYS PAIENTEflraszs I974 3.794379 sumanra INVENTO CHARLES E. GREUZA Y Lou/s L. HENKIN MA HONEY, HORNBA KER AND SCH/CK ATTORNEYS PATENIEDFB26 i974 3,7 94,7 7 9 SHEET '4 0r 4 INVENTORS. CHARLES E. GREUZARD BY LOU/5' L. HENK/N I MAHONE Y, HORNBAKER AND SCHICK ATY ORNEYS HEADPHONES FOR REPRODUCING FOUR-CHANNEL SOUND BACKGROUND OF THE INVENTION This invention relates to specifically formed headphones adapted for reproducing four-channel sound, and more particularly, to unique headphones, each having forward and rearward, segregated, mixing chambers, each capable of receiving a different single channel of four-channel sound for effectively reproducing such four-channel sound with a similar effect to four-channel remote speakers. The result is that with the headphones of the present invention, a personalization of four-channal sound is obtained, the same function of earphones as has been previously done with monaural and stereophonic sounds, yet the full effects of four-channel sound remain uninhibited just as if four-channel sound remote speakers were being used.

In the reproduction of monaural or single channel sound, merely a single sound emitting device is required and this is true whether or not the single sound emitting device may be made up of a group of speakers, each adapted for more perfectly reproducing single tone ranges of the single channel sound. Adapting the monaural or single channel sound to the personalization of headphones was obviously a relatively simple matter, there being one sound emitting device for each of the ears of the person wearing the headphones and again, whether or not each of these sound emitting devices included a series of sound emitters, each adapted for a particular tone range of the overall sound being received. The important point is that whether by a remote sound emitting device, such as a speaker device, or whether by a single or set of headphones for the personalization, it was readily distinguishable by the person listening to such sound that it was being received from a single source.

With the advent of stereophonic sound in the form of two-channel sound, for proper reproduction thereof, it was necessary to provide two spaced, remote, sound emitting devices or speakers, the best results being when the person listening to the sound is positioned between the speakers. Thus, the adaption of two-channel sound to the personalization of earphones was still a relatively simple matter, it merely being necessary to provide earphones, each having a separate sound emitting device therein and each of the separate sound emitting devices being connected to the separate two sound channels. In this manner, two-channel sound could be and is effectively reproduced both with remote speakers systems or personalized headphones, in either case the person listening to the same having some effect of sitting within the reproduced sound.

With the introduction of four-channel sound, however, completely different problems are presented in adapting the reproduction of the same from the remote speaker systems to the personalized headphone system. With four-channel sound, it is not merely the effect of being positioned between sound emitting devices so as to be partially enveloped by the sound from direct opposite sides as in two-channel sound, but it is the effect of being completely enveloped by sound with the ears of the person receiving such sound detecting sounds coming from the rearward directions and the forward directions, and from both sides. The complexity of the problems involved can be even more clearly appreciated when it is considered that with monaural or single channel sound and stereophonic in the form of twochannel sound, there is no forward and rearward directional sound effect and it is merely necessary to position the sound emitting devices adjacent each of the ears and direct the sound into the ears.

In four-channel sound, however, the reproduction of the four direction sound and the recognition thereof by the ears must be on a directional lbasis, one sound emitting device at either side from forward and the same from rearwardJFurthermore, none of the sound emitting devices in four channel sound reproduction can be directed specifically at the ear for the reason that it would be impossible for the ear to truly detect the direction thereof when the ear is merely receiving sounds from sound emitting devices merely slightly forwardly and rearwardly of each other.

In the reproduction of four-channel sound with speakers systems, it is possible to authentically reproduce the four-channel sound merely by the remote placements of the various channel receiving speakers. In other words, if the person listening to the fourchannel sound is positioned surrounded by the individual channel speaker systems, it is readily recognized by the ears that one channel is being received generally from each of the forward sides and one channel is being received from each of the rearward sides, again due to the remoteness of the speaker systems. Using the simple concepts of the prior headphone constructions, however, the effect of attempting to personalize fourchannel sound to headphone reproduction is to move each of the remote speakers or sound emitting devices into relatively close forward and rearward proximity, necessary for the relatively small headphone units and this as hereinbefore pointed out, makes it virtually impossible with the prior headphone concepts for the ears to detect the forward and rearward directional reception of the sounds, thereby completely destroying the four-channel sound effect.

OBJECTS AND SUMMARY OF THE INVENTION It is, therefore, an object of this invention to provide headphones adapted for reproducing four-channel sound wherein a reasonable reproduction of fourchannel sound is obtained, while still maintaining the headphones of a reasonable and usable size. According to broader concepts of the presentinvention, each of the earphones is provided with forward and rearward mixing chambers, each having a sound emitting device therein and with the mixing chambers being separated in each headphone by a generally vertical partition. The sound emitting devices in the respective mixing chambers are directed at least partially against chamber walls, rather than directly at the central opening inwardly communicating with the ear of the person wearing the headphones. Thus, the sounds produced in the various mixing chambers give directional reproduction readily detected by the ear and reproducing the forward and rearward directional transmission for accomplishing the reproduction of the four-channel sound.

It is a further object of this invention to provide headphones adapted for reproducing four-channel sound involving the foregoing broad concepts wherein fourchannel sound reproductions of maximum quality are produced by specific contouring of the mixing chamber wall and the direction of sound from the sound transmitting devices at specific locations on said wall. For

maximum quality and authenticity of four-channel sound reproduction, each of the forward and rearward mixing chambers of each of the headphones is preferably generaly ovoidal in horizontal cross-sections and preferably generally elipsoidal in vertical cross-sections in the extensions thereof within the headphone casings from the casing inner sides, the horizontal crosssectional ovoidal shapes having their maximum outsound reproduction.

It is still a further object of this invention to provide headphones adapted for reproducing four-channel sound wherein even increased authenticity of sound reproduction may be produced with a common integrating chamber communicating with the respective forward and rearward mixing chambers of each of the earphones. Each of the earphones is provided with a generally central opening communicating with each of the mixing chambers for positioning at the ear of the person receiving the sound, such central opening preferably being of appropriate size at least for fully receiving the ear therein and with the depth of the central opening or the outward dimensions thereof to the mixing chambers being sufficient for providing the integrating chamber adjacent the ear and extending forwardly and rearwardly various amounts for various outward communications with the mixing chambers. Thus, each of the mixing chambers communicates to the headphone central opening at either side of the vertical partition and into the integrating chamber for transmission from such integrating chamber to the ear, even more completely reproducing the four-channel sound and giving the effect of sound emitting devices a far greater distance from the ear than is the actual case.

It is an additional object of this invention to provide headphones adapted for reproducing four-channel sound of the foregoing general character which, by simple switch means, may be adapted compatible with virtually any form four-channel sound system, as well as providing certain of the four-channel sound effects from two-channel sound systems. The various sound emitting devices of the headphones are connected to the respective sound producing devices through a multi-positionable switch which may be adjusted for transmitting the sound of any given sound transmission device to any given sound emitting device in any of the four mixing chambers of the headphone set. In this manner, all possible combinations of sound transmission to individual headphone mixing chambers may be obtained without a separate, specific wiring being required for each individual case, including that where sterophonic or two-channel sound is to be used.

Other objects and advantages of the invention will be apparent from the following specification and the accompanying drawing which are for the purpose of illustration only.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, front elevational view illustrating an embodiment of the headphones of the present invention in proper position covering the ears of a person wearing a set of such headphones;

FIG. 2 is an enalarged, fragmentary, horizontal sectional view, looking in the direction of the arrows 2-2 in FIG. 1, and showing the embodiment of the headphones of the present invention oppositely connected to a multi-positionable switch and further illustrating the relative positioning of theears within central openings of the headphones of the person wearing the headphones;

FIG. 3 is a fragmentary, vertical perspective sectional view, looking in the direction of the arrows 3-3 in FIG. 2, more clearly showing the internal construction of one of the headphones of FIG. 2, an approximate quarter section being taken from a forward mixing chamber portion of the headphone to even further illustrate the internal construction of the headphone mixing chambers;

FIG. 4 is a diagramatic top plan view of an orchestra with sound producing devices positioned therearound and to which the sound emitting devices of the head phones might be connected for illustrating one use of the headphones of the present invention;

FIG. 5 is a horizontal sectional view similar to the view of FIG. 2, but only of a single headphone, illustrating a second embodiment of the headphones of the present invention;

FIG. 6 is a vertical perspective sectional view, looking in the direction of the arrows 66 in FIG. 5, and similar to FIG. 3;

FIG. 7 is a vertical sectional view, looking in the direction of the arrows 77 in FIG. 6;

FIG. 8 is a horizontal sectional view similar to the view of FIG. 5, illustrating a third embodiment of the headphones of the present invention; and

FIG. 9 is a vertical sectional view, looking in the direction of the arrows 99 in FIG. 8.

Description of the'Best Embodiments Contemplated:

Referring to FIGS. 1 to 3 of the drawings, an embodiment of the headphones incorporating the principles of the present invention is illustrated, the two headphones of a set being virtually identical with the usual opposite positioning over the two ears of a person using the same. As shown, each headphone includes a main hollow casing gnerally indicated at 10 segregated into outward, somewhat bulbous, forward and rearward acoustic mixing chambers generally indicated at 12 and 14, respectively. The segregation of the casing 10 to separate the

mixing chambers

12 and 14 is preferably accomplished by a generally forwardly and rearwardly central and generally vertically extending partition 16 which terminates inwardly at an outer portion of an preferably forwardly and rearwardly generally centrally segregating a generally central ear opening 18, the ear opening, in this case being concentrated centrally.

The ear opening 18, for maximum results, is of outward depth or dimensions from a generally flat casing inner side 20 at least sufficient to fully receive an ear 22 of a person wearing the particular headphone while still maintaining the partition 16 spaced outwardly therefrom, thereby providing an acoustic integrating chamber 24 outwardly of the ear 22 and inwardly of the inner termination of the partition 16. The ear opening 18 and, therefore, the integrating chamber 24, extends forwardly and outwardly into communication with the forward mixing chamber 12 forwardly adjacent the partition l6, and rearwardly and outwardly into communication with the rearward mixing chamber 14 rearwardly adjacent the partition 16. The relationship between the outward depth of the ear opening 18, the size of such ear opening relative to the ear 22 and the outward positioning of the partition 16 is illustrated in FIG. 2, it being seen that the integrating chamber 24 extends forwardly and rearwardly between the communication thereof with the forward and

rearward mixing chambers

12 and 14 as well as communicating with the ear 22, the depth of the opening being formed by the outward thicknesses of a usual resilient material head pad 26 and an inner wall 28 of the main portion of the casing 10. Obviously, if desired, the inner wall 28 may actually connect to the inner end of the partition 16 with appropriate perforations therethrough into the central ear opening 18.

As further shown in FIG. 2, the head pad 26 and the casing inner wall 28 close the forward and

rearward mixing chambers

12 and 14 except for the opening thereof, into the integrating chamber 24, whether adjacent the partition 16, or otherwise, the walls of the mixing chambers outwardly of the casing inner side 20 or the casing inner wall 28 preferably being specifically arcuate, including the walls formed by the partition 16. As may be seen in both FIGS. 2 and 3, each of the forward and

rearward mixing chambers

12 and 14 are preferably of generally ovoidal horizontal crosssections gradually diminishing to the upward and downward extremities thereof and having maximum outward and depth dimensions from the casing inner side 20 toward the partition 16, that is, at locations lesser horizontal distances from the casing partition than the horizontal midpoint distances of the mixing chambers. Furthermore, the forward and

rearward mixing chambers

12 and 14 are preferably elipsoidal in vertical cross-sections outwardly from the casing inner side 20, again diminishing toward the forward and rearward extremities thereof. 1

A sound emitting device 30, such as the usual miniature earphone speakers, is positioned in each ofthe forward and rearward mixing

chambers

12 and 14, the forward mixing chamber device 30 being in the forward extremity thereof and the rearward mixing chamber device 30 being in the rearward extremity thereof. The separate sound emitting devices 30 may be of any usual form including single overall tone range speakers or a I series of different tone range speakers to cover the entire tone range as is usual practice and well known to those skilled in the art. More important, the sound emitting devices 30 are positioned within the forward and rearward mixing

chambers

12 and 14 so as to not principally direct the sound therefrom directly toward the ear opening 18 and the integrating chamber 24, but rather to direct the sound therefrom principally toward inner wall surfaces 32 of the mixing chamber, for best results, preferably principally toward the arcuate inner wall surfaces formed by the partition 16 in each of these mixing chambers.

For expediency of manufacturing, the main portions of the casing may be of the usual molded plastics in the specific shapes described. Also, the head pad 26 may be of the usual sponge or foamed plastics to provide the usual resilient qualities thereof. The sound emitting devices 30, as hereinbefore described, may be of usual construction merely properly contoured for mounting in the forward and rearward mixing

chambers

12 and 14 as described.

Each of the sound emitting devices 30 is separately wired preferably through a multi-positionable switch 34, and from such switch, to individual sound producing devices 36 shown diagramatically in FIG. 4. Referring simultaneously to FIGS. 2 and 4 for illustration of a use of the headphones of the present invention, FIG. 4 illustrates diagramatically an orchestra 38 denoted by the orchestra leader as facing the bottom of the sheet of the drawing, the sound producing devices 36 being equally spaced around the orchestra and, in this case, being sound pick-up devices. Continuing the example and considering the usual arrangement of four-channel sound reception, the lowest or forward sound producing device 36 of FIG. 4 would be connected to the sound emitting device 30 of the left earphone forward mixing chamber 12 of FIG. 2, the left rear sound producing device 36 of FIG. 4 to the sound emitting device 30 of the left headphone rearward mixing chamber 14, the right forward sound producing device 36 of FIG. 4 to the sound emitting device 30 of the right headphone forward mixing chamber, and the right rearward sound producing device 36 of FIG. 4 to the sound emitting de vice 30 of the right headphone rearward mixing chamber 14.

Thus, the effect to the person wearing the headphones would be that of being positioned centrally of the orchestra and facing forwardly in the same direction of the orchestra. If the effect were desired of being in the position of a person in the audience at the front of the orchestra, the connections to the forward and rearward mixing

chambers

12 and 14 of an individual earphone of FIG. 2 would be directly reversed and this is one of the purposes of the multi-positionable switch 34 to accomplish this merely by changing the position of the switch. Also, it is obvious that although the illustration of FIG. 4 is a live orchestra 38, a four-channel tape of a similar recording of the orchestra would produce precisely the same effect, the particular sound producing devices 36 being the sound pick-ups of the tape connected to the various of the sound emitting devices 30 in the

headphone mixing chambers

12 and 14.

The foregoing has given two possible connections of the headphones of the present invention through the v multi-positionable switch 34 and various other positions of the switch would be other possible combina tions varied from that set forth. Various present day four-channel sound systems have various theories as to the manner of connecting a particular of the mixing

chambers

12 or 14 to the particular of the sound producing devices 36 or the equivalent tape channel pickups and the switch can be arranged in a manner well known to those skilled in the art so as to provide for each of these various possible connections merely by a repositioning of the switch. Still in addition, certain of the effects of four-channel sound can be reproduced from two-channel sound tapes or sound producing devices 36 and the switch 34 may have additional positions for accommodating the various possible connections into the earphones of the present invention of such two-channel sound, again, all obvious to those skilled in the art.

Regardless of the particular line of connections between the sound producing devices 36 or their equivalent and the sound emitting devices 30 of the various mixing

chambers

12 and 14, with the particular construction of headphones described, each sound emitting device 30 will reproduce its particular sound and direct the same toward the arcuate surfaces of the

particular mixing chamber

12 or 14 principally toward the particular partition 16 and with the specific contouring of the mixing chamber as hereinbefore described, such sound will deflect from the arcuate walls and be mixed giving it both the quality of depth and direction followed by integration with the other mixing chamber of that particular headphone as the sound leaves the mixing chamber and enters the integrating chamber 24 of the particular ear opening 18, finally being received by the ear 22. The overall effect is that the human car 22 will be given the illusion of sound depth approaching that of actually being present at and listening to the sound producing media, whether the orchestra 38 or otherwise. At the same time, the human ear 22 will detect separated direction of reception, from generally forward as a result of the forward mixing chambers 12 and from generally rearward as a result of the rearward mixing chambers 14, all of which will give a maximum quality of four-channel sound reproduction.

Referring to FIGS. through 7, a second embodiment of the headphones of the present invention is illustrated therein, the headphones shown being identical to those of FIGS. 1 through 3 with the sole exception of the addition of similar arcuate protrusions 40, one each protruding into each of the mixing

chambers

12 and 14 principally from the inner wall surfaces 32 at opposite sides of the partition 16 and covering the major portion of such partition inner wall surfaces. As shown particularly in FIGS. 6 and 7, the protrusions 40 are preferably elipsoidal in vertical cross-sections diminishing smoothly inwardly and outwardly of the easing inner side 20 and terminating inwardly spaced outwardly of the inner termination of the partition 16. It is felt that, at least with certain types of sound and certain types of sound reproduction that the protrusions 40 will increase the quality of mixing within the

particular mixing chamber

12 or 14 from the particular sound emitting device to give increased qualities of sound reproduction to the ear 22.

Referring to FIGS. 8 and 9, a third embodiment of the headphones of the present invention is illustrated therein, again, the headphones shown being identical to those of FIGS. 1 through 3 with the exception of a different overall extension of the casing inner wall 28, a lesser sized formation of the head pad 26 so as to produce a far more extensive ear opening 18 and integrating chamber 24, and a different communication between the mixing

chambers

12 and 14 and the ear central opening 18 and integrating chamber 24. As shown, the casing inner wall 28 is preferably solid in an area encompassing the inner termination of the partition 16, such area extending both forwardly and rearwardly over a partial inward termination of the mixing chambers. This solid area of'the casing inner wall 28 is preferably circular in extremity contour and forwardly, rearwardly, above and below this solid area, the casing inner wall is formed with a multiplicity of perforations 42 therethrough communicating upwardly into each of the mixing

chambers

12 and 14.

The head pad 26 is of greatly reduced cross-sectional dimensions and circumscribes the casing inner wall 28 only at the extremities thereof in all directions beyond the location of the perforations 42. The result is that the now reduced head pad 26 in the positioning thereof against the head of a person wearing the headphones seals off a much more extensive ear central opening 18, although the ear is still preferably positioned centrally thereof at the partition 16 and inwardly of the solid area of the casing inner wall 28. The integrating chamber 24, however, is greatly forwardly, rearwardly, upwardly and downwardly enlarged, but still communicating from the mixing

chambers

12 and 14 through the perforations 42 into the integrating chamber at the extremities thereof, the integrating chamber extending fully between the mixing

chambers

12 and 14 and fully in communication with the ear 22.

This third embodiment of the headphones of the present invention in view of the increased size of the ear central opening 18 and the integrating chamber 24, will even further increase the separation of sound from each of the

individual mixing chambers

12 and 14 in order to permit the ear to receive the effect of spaced forwardly and rearwardly sound reproduction. In this manner, a more perfect fourchannel sound reproduction is produced while still maintaining such reproduction in personalized headphones. Furthermore, this increased sound separation effect of the increased integrating chamber 24 will cooperate with the mixed sound of the mixing

chambers

12 and 14, whether these mixing chambers and the partition 16 are of the form shown in FIGS. 1 through 3 of FIGS. 5 through 7.

Thus, according to the principles of the present invention, headphones are provided for quality reproduction of four-channel sound, such result not being heretofore possible with the prior headphones construction. Furthermore, according to certain of the principles of the present invention, by connection of the unique headphones through a multi-positionable switch, it is possible to adapt the same to virtually any form or therory of four-channel sound merely by a repositioning of the switch. Still in addition, with the use of the head phones of the present invention and preferably again through the muIti-positionable switch, it is possible to make use of two-channel sound and give the same certain of the effects of four-channel sound.

We claim:

I. In a headphone construction, the combination of: a main generally hollow casing having a generally central opening at an inner side positionable at an ear of a person, said casing enclosing forwardly and rearwardly extending segregated acoustic mixing chambers separated by a portion of said casing and each opening through said casing central opening; and a sound emitting device in each of said mixing chambers positioned directing sound into the respective of said mixing chambers, said sound emitting devices in each of said mixing chambers being principally directed toward walls of said respective mixing chambers formed by said portion of said casing separating said mixing chambers.

2. The headphone construction as defined in claim 1 in which said casing central opening forming an acoustic integrating chamber between said mixing chambers and said ear inwardly of said portion of said casing separating said mixing chambers.

3. The headphone construction as defined in claim 1 in which each of said mixing chambers in extension thereof outwardly and forwardly and rearwardly from said casing inner side is generally ovoidal in horizontal cross section and generally ellipsoidal in vertical cross section.

4. In a headphone construction, the combination of: a main casing having a generally vertical partition separating said easing into forward and rearward acoustic mixing chambers, said casing being adapted for positioning with a casing inner side against the head of a person covering an ear and with said partition at said ear, said casing and said partition forming walls defining said chambers; said forward mixing chamber opening through said casing forwardly of said partition to said ear; said rearward mixing chamber opening through said casing rearwardly of said partition to said ear; and asound emitting device in each of said mixing chambers directing sound into the respective one of said mixing chambers, said sound emitting devices in each of said mixing chambers being principally directed toward walls of said respective chambers formed by said partition.

5. The headphone construction as defined in claim 4 in which said sound emitting device in said forward mixing chamber is at a forward extremity of said forward mixing chamber directed rearwardly; and in which said sound emitting device in said rearward mixing chamber is at a rearward extremity of said rearward mixing chamber directed forwardly.

6. The headphone construction as defined in claim 4 in which said forward and rearward mixing chambers communicate through said casing inner side through an acoustic integrating chamber in said casing inwardly of an inner termination of said partition.

7. The headphone construction as defined in claim 4 in which said walls of said forward and rearward mixing chambers outwardly of said casing inner side including said partition are arcuate in horizontal cross section.

8. The headphone construction as defined in claim 4 in which said walls of said forward and rearward mixing chambers outwardly of said casing inner side including said partition are arcuate in vertical cross section.

9. The headphone construction as defined in claim 4 in which said walls of said forward and rearward mixing chambers outwardly of said casing inner side including said partition are arcuate in both vertical and horizontal cross section.

10. The headphone construction as defined in claim 4 in which said walls of said forward and rearward mixing chambers outwardly of said casing inner side including said partition are generally ellipsoidal in vertical cross section.

11. The headphone construction as defined in claim 4 in which said walls of said forward and rearward mixing chambers outwardly of said casing inner side including said partition are generally ovoidal in horizontal cross section.

12. The headphone construction as defined in claim 4 in which said walls of said forward and rearward mixing chambers outwardly of said casing inner side including said partition are generally ellipsoidal in vertical cross section and generally ovoidal in horizontal cross section, said mixing chamber ovoidal horizontal cross sections having maximum outward dimensions at locations lesser horizontal distances from said casing partition than horizontal midpoint distances of said mixing chambers from said partition.

13. The headphone construction as defined in claim 4 in which similar arcuate protrusions are formed principally on said casing partition projecting principally from said partition into each of said forward and rearward mixing chambers.

14. The headphone construction as defined in claim 4 in which similar arcuate protrusions are formed principally on said casing partition projecting into each of said forward and rearward mixing chambers principally from said partition, said forward mixing chamber protrusion projecting principally from said partition generally toward said forward mixing chamber forward extremity, said rearward mixing chamber protrusion projecting principally from said partition generally toward said rearward mixing chamber rearward extremity, said forward and rearward mixing chamber protrusions in projection principally from said casing partition being generally ellipsoidal in both vertical and horizontal cross section.

15. The headphone construction as defined in claim 4 in which similar arcuate protrusions are formed principally on said casing partition projecting into each of said forward and rearward mixing chambers principally from said partition, said forward mixing chamber protrusion projecting principally from said partition, generally toward said forward mixing chamber forward extremity, said rearward mixing chamber protrusion projecting principally from said partition generally toward said rearward mixing chamber rearward extremity; said forward and rearward mixing chamber protrusions covering major portions of walls of said casing partition.

Claims

1. In a headphone construction, the combination of: a main generally hollow casing having a generally central opening at an inner side positionable at an ear of a person, said casing enclosing forwardly and rearwardly extending segregated acoustic mixing chambers separated by a portion of said casing and each opening through said casing central opening; and a sound emitting device in each of said mixing chambers positioned directing sound into the respective of said mixing chambers, said sound emitting devices in each of said mixing chambers being principally directed toward walls of said respective mixing chambers formed by said portion of said casing separating said mixing chambers.

4. In a headphone construction, the combination of: a main casing having a generally vertical partition separating said casing into forward and rearward acoustic mixing chambers, said casing being adapted for positioning with a casing inner side against the head of a person covering an ear and with said partition at said ear, said casing and said partition forming walls defining said chambers; said forward mixing chamber opening through said casing forwardly of said partition to said ear; said rearward mixing chamber opening through said casing rearwardly of said partition to said ear; and a sound emitting device in each of said mixing chambers directing sound into the respective one of said mixing chambers, said sound emitting devices in each of said mixing chambers being principally directed toward walls of said respective chambers formed by said partition.