U.S. patent number 3,794,779 [Application Number 05/173,809] was granted by the patent office on 1974-02-26 for headphones for reproducing four-channel sound.
This patent grant is currently assigned to Thomas P. Mahoney, Victor B. Morgan, George E. Schick. Invention is credited to Charles E. Greuzerd, Louis Lawrence Henkin.
United States Patent |
3,794,779 |
Greuzerd , et al. |
February 26, 1974 |
HEADPHONES FOR REPRODUCING FOUR-CHANNEL SOUND
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.
Inventors: |
Greuzerd; Charles E. (Garden
Grove, CA), Henkin; Louis Lawrence (Huntington Park,
CA) |
Assignee: |
Morgan; Victor B. (Los
Alamitos, CA)
Mahoney; Thomas P. (Santa Monica, CA)
Schick; George E. (Santa Monica, CA)
|
Family
ID: |
22633589 |
Appl.
No.: |
05/173,809 |
Filed: |
August 23, 1971 |
Current U.S.
Class: |
381/5; 381/309;
381/371; 381/19 |
Current CPC
Class: |
H04R
1/1075 (20130101); H04R 5/02 (20130101); H04R
5/033 (20130101); H04R 1/1041 (20130101); H04R
2205/022 (20130101) |
Current International
Class: |
H04R
5/02 (20060101); H04R 5/00 (20060101); H04R
1/10 (20060101); H04R 5/033 (20060101); H04m
001/05 () |
Field of
Search: |
;179/1G,1GA,156R,182 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cooper; William C.
Attorney, Agent or Firm: Mahoney, Schick & Cislo
Claims
We claim:
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.
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 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.
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.
Description
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 two-channel 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 basis, one sound emitting device at either side from
forward and the same from rearward. Furthermore, 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
four-channel 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 four-channel 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 four-channel sound is obtained, while still
maintaining the headphones of a reasonable and usable size.
According to broader concepts of the present invention, 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 four-channel 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 cross-sectional ovoidal shapes having
their maximum outward extension dimensions in horizontal directions
toward the spearating vertical partition. Furthermore, the sound
emitting devices in each of the mixing chambers are at chamber
locations generally a maximum distance from the separating vertical
partitions and preferably directed generally toward chamber walls
at least partially formed by the vertical partition. These
preferred contours and sound direction produce a maximum mixing of
the sounds in each of the mixing chambers so as to produce the
forward and rearward sound transmission distinguishment by the ear
receiving such sound 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 the ears 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 there- around and to which the sound
emitting devices of the headphones 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 6--6 in FIG. 5, and similar to FIG. 3;
FIG. 7 is a vertical sectional view, looking in the direction of
the arrows 7--7 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 9--9 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 16, 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 cross-sections
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.
A sound emitting device 30, such as the usual miniature earphone
speakers, is positioned in each of the 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 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 10
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 device 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 multi-positionable switch 34
and various other positions of the switch would be other possible
combinations 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 pick-ups 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
ear 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. 5 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 casing 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 30 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
four-channel 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 headphones of the present invention and
preferably again through the multi-positionable switch, it is
possible to make use of two-channel sound and give the same certain
of the effects of four-channel sound.
* * * * *