Speaker apparatus
United States Patent 3900707
Speaker apparatus adapted to be coupled electrically to a sound reproducing system for reproducing four separate sources of sound and adapted to be used within close proximity to the ears of the user, includes a first and second pair of oppositely-disposed spaced-apart members each having respective first and second chambers opening substantially toward one another, a first pair of spaced-apart cavities opening into the first chamber, a second pair of spaced-apart speaker cavities opening into the second chamber, a first pair of speaker units mounted within the first pair of cavities and positioned generally facing the second chamber, a second pair of speaker units mounted within the second pair of cavities and positioned generally facing the first chamber, and a pair of first and second baffles mounted at least partially within the respective first and second chambers, the first baffle member being disposed between one of the first pair of cavities and the opening of the first chamber, the second baffle member being disposed between one of the second pair of cavities and the opening of the chamber so that when the sound reproduction system energizes the speaker units, the sound emanating from the speaker units of each of the pairs of speaker units is caused to be out of phase with one another at the opening to the chambers. The first and second baffle members partially block one of the first and second pairs of cavities, respectively, to control the effective sound pressure level at the opening to the chambers. The baffle members also block to a lesser extent the other ones of the pairs of speaker cavities to produce the phase delay. A bleeder tube connects the first and second chambers in fluid communication to equalize the sound pressure levels therebetween so that the sound pressure levels and the phase relationships can more closely approximate the natural sound being reproduced.
US Patent References:
HEADPHONE ASSEMBLY
Hanson - February 1974 - 3792754
HEADPHONES FOR REPRODUCING FOUR-CHANNEL SOUND
Greuzerd et al. - February 1974 - 3794779
FOUR-CHANNEL HEADPHONE
Ohta - March 1974 - 3796840
Stereophonic transducer arrangement
Fixler - January 1975 - 3863028
HEADPHONE ASSEMBLY
Hanson - February 1974 - 3792754
HEADPHONES FOR REPRODUCING FOUR-CHANNEL SOUND
Greuzerd et al. - February 1974 - 3794779
FOUR-CHANNEL HEADPHONE
Ohta - March 1974 - 3796840
Stereophonic transducer arrangement
Fixler - January 1975 - 3863028
Application Number:
05/367521
Publication Date:
08/19/1975
Filing Date:
06/06/1973
View Patent Images:
Export Citation:
Assignee:
Hear-Muffs, Inc. (Downers Grove, IL)
Primary Class:
Other Classes:
381/309, 381/19, 381/308
International Classes:
H04R1/10; H04R5/033; H04R5/00; H04M1/05; H04R5/00
Field of Search:
179/156A,1GQ,1GP,146H
Primary Examiner:
Cooper, William
Attorney, Agent or Firm:
Kleinke, Bernard Speckman Thomas Kalinowski Leonard L. W. J.
Claims:
What is claimed is
1. Speaker apparatus adapted to be worn on the head of a user and adapted to be coupled to a sound reproducing system for causing sounds to be emitted from said apparatus, said speaker apparatus comprising:
2. Speaker apparatus according to claim 1, wherein said first and second baffle means partially block the opening of the other one of said first pair of cavities and partially block the opening of the other one of said second pair of cavities, respectively, to reduce sound pressure intensities from the speaker units mounted therein.
3. Speaker apparatus according to claim 2, wherein said first and second baffle means block said openings of the other ones of said first and second pairs of cavities to reduce sound pressure levels within the range of 30 percent to 40 percent of the effective sound levels of the speaker units mounted therein.
4. Speaker apparatus according to claim 3, wherein said baffle means causes a 35 percent reduction of said effective sound pressure levels.
5. Speaker apparatus according to claim 3, wherein said first and second baffle means partially block the opening of said one of said first pair of cavities and partially block the opening of said one of said second pair of cavities respectively to reduce the sound pressure intensities from the speaker units mounted therein.
6. Speaker apparatus according to claim 1, further including a tube connecting said chambers in fluid communication.
7. Speaker apparatus according to claim 1, further including a transverse member interconnecting said pair of spaced-apart members, said transverse member and said spacedapart member forming a U-shaped member composed of resilient material.
8. Speaker apparatus according to claim 7, further including spring means for urging resiliently said spaced-apart members together.
9. Speaker apparatus according to claim 1, wherein said means defining a pair of longer rear paths include first and second baffle means mounted at least partially within said first and said second chambers respectively for at least partially defining said pair of longer rear paths, said first baffle means being disposed between said rear one of said first pair of cavities and the central portion of said first opening of said first chamber, said second baffle means being disposed between said rear one of said second pair of cavities and the central portion of said second opening of said second chamber.
10. Speaker apparatus adapted to be energized by an independent sound signal system comprising: a member composed of soft resilient material having an elongated transverse block adapted to engage and extend across the back portion of the head of a user and having a pair of legs extending from the end portions of said block in a spaced-apart manner and able to be spread apart further by means of the resiliency of said rear portion to grip snugly the head of the user therebetween to at least partially support the assembly thereon and to fit over the ears of the user; means defining a pair of cavities in the ear-engaging portions of said legs having oppositely-disposed openings; a pair of speaker means mounted within said cavities having axes of sound extending through said openings when said assembly is in position over the ears of the user; wire means adapted to connect electrically said speaker means to the sound signal system for driving said speaker means; and spring means for biasing said legs inwardly, wherein said member includes an internal groove therein, said spring means including a U-shaped spring clip mounted within the complementary internal groove in said member.
11. Speaker apparatus according to claim 10, wherein said spring means further includes a second U-shaped spring clip mounted within said internal groove.
1. Speaker apparatus adapted to be worn on the head of a user and adapted to be coupled to a sound reproducing system for causing sounds to be emitted from said apparatus, said speaker apparatus comprising:
2. Speaker apparatus according to claim 1, wherein said first and second baffle means partially block the opening of the other one of said first pair of cavities and partially block the opening of the other one of said second pair of cavities, respectively, to reduce sound pressure intensities from the speaker units mounted therein.
3. Speaker apparatus according to claim 2, wherein said first and second baffle means block said openings of the other ones of said first and second pairs of cavities to reduce sound pressure levels within the range of 30 percent to 40 percent of the effective sound levels of the speaker units mounted therein.
4. Speaker apparatus according to claim 3, wherein said baffle means causes a 35 percent reduction of said effective sound pressure levels.
5. Speaker apparatus according to claim 3, wherein said first and second baffle means partially block the opening of said one of said first pair of cavities and partially block the opening of said one of said second pair of cavities respectively to reduce the sound pressure intensities from the speaker units mounted therein.
6. Speaker apparatus according to claim 1, further including a tube connecting said chambers in fluid communication.
7. Speaker apparatus according to claim 1, further including a transverse member interconnecting said pair of spaced-apart members, said transverse member and said spacedapart member forming a U-shaped member composed of resilient material.
8. Speaker apparatus according to claim 7, further including spring means for urging resiliently said spaced-apart members together.
9. Speaker apparatus according to claim 1, wherein said means defining a pair of longer rear paths include first and second baffle means mounted at least partially within said first and said second chambers respectively for at least partially defining said pair of longer rear paths, said first baffle means being disposed between said rear one of said first pair of cavities and the central portion of said first opening of said first chamber, said second baffle means being disposed between said rear one of said second pair of cavities and the central portion of said second opening of said second chamber.
10. Speaker apparatus adapted to be energized by an independent sound signal system comprising: a member composed of soft resilient material having an elongated transverse block adapted to engage and extend across the back portion of the head of a user and having a pair of legs extending from the end portions of said block in a spaced-apart manner and able to be spread apart further by means of the resiliency of said rear portion to grip snugly the head of the user therebetween to at least partially support the assembly thereon and to fit over the ears of the user; means defining a pair of cavities in the ear-engaging portions of said legs having oppositely-disposed openings; a pair of speaker means mounted within said cavities having axes of sound extending through said openings when said assembly is in position over the ears of the user; wire means adapted to connect electrically said speaker means to the sound signal system for driving said speaker means; and spring means for biasing said legs inwardly, wherein said member includes an internal groove therein, said spring means including a U-shaped spring clip mounted within the complementary internal groove in said member.
11. Speaker apparatus according to claim 10, wherein said spring means further includes a second U-shaped spring clip mounted within said internal groove.
Description:
The present invention relates to a speaker apparatus, and it more particularly relates to a speaker apparatus having four speakers for reproducing four channels of sound from a sound reproduction system in a realistic quadrophonic manner.
Four channel stereo headphones have been employed to reproduce four channels of sound by providing two pairs of closely-spaced speakers adapted to be secured to the head of the user in close proximity to the ears in a manner somewhat similar to conventional headphones having only two speakers, one for each ear. However, while such four channel headphones having relatively closely spaced speakers have been successful in reproducing four channels of sound, they have not been entirely satisfactory for some applications in that they have not successfully reproduced quadraphonic sensations to a listener as compared to relatively widely spaced-apart speakers, since such speaker systems very closely approximate the acoustic effect present in an actual concert hall or elsewhere where the original sounds are reflected by walls, ceiling, floor and other objects within the room and converge upon the listener's ears with randomly varying time delays. Thus, it would be highly desirable to have a closely-spaced speaker apparatus which would reproduce four channels of sound in such a manner that it closely approximates the sound produced by four speakers spaced apart by a relatively great distance, and would provide an effect of "presence" to the listener as if he were actually present at the live performance of the original sound, the speaker apparatus being in the form of headphones or other apparatus adapted to be used in relatively close proximity to the ears of the user.
Therefore, the principal object of the present invention is to provide a new and improved speaker assembly adapted to be used in close proximity to the ears of the user and adapted to reproduce four channels of sound from a sound reproduction system in a realistic quadraphonic manner.
Briefly, the above and further objects are realized in accordance with the present invention by providing a new and improved speaker apparatus, adapted to be coupled electrically to a sound reproducing system, which includes a first and second pair of oppositely-disposed spaced-apart members each having respective first and second chambers opening substantially toward one another, a first pair of spaced-apart speaker cavities opening into the first chamber, a second pair of spaced-part speaker cavities opening into the second chamber, a first pair of speaker units mounted within the first pair of cavities and positioned generally facing the second chamber, a second pair of speaker units mounted within the second pair of cavities and positioned generally facing the first chamber, and a pair of first and second baffle members mounted at least partially within the first and second chambers, respectively, the first baffle member being disposed between one of the first pair of cavities and the opening of the first chamber, the second baffle member being disposed between one of the second pair of cavities and the opening of the second chamber so that when the system producing the sounds energizes the speakers, the sound emanating from the speaker units of each of the pairs of units is caused to be out of phase with one another at the opening to the chambers. As a result, when a user positions his head between the first and second pair of oppositely-disposed members and when the sound reproducing system energizes the speaker units, the user experiences a psychoacoustic quadraphonic sensation in that the four speakers of the apparatus of the present invention are physically spaced apart and the pairs of speakers on each side of the head of the user are physically arranged to produce sounds which are out of phase with one another. The baffle members of the present invention partially block one of the first and second pairs of cavities to control the effective sound pressure level at the openings of the chambers from the other one of the speaker units to equalize the sound pressure levels between the two speaker units on either side of the head of the user. A bleeder tube connects the two chambers in fluid communication to equalize the sound pressure levels of both chambers to approximate further the actual psychoacoustic phenomena occurring naturally and to provide the necessary phase relationship between the speakers.
Other objects and advantages of the present invention will become apparent from a reading of the following detailed description and the accompanying sheets of drawings, wherein:
FIG. 1 is a pictorial view of speaker apparatus which is adapted to be used with a sound reproduction (not shown), and which is constructed in accordance with the present invention;
FIG. 2 is an enlarged cross-sectional view of the speaker apparatus of FIG. 1 taken substantially along the line 2--2 thereof; FIG. 3 is an enlarged detailed view of the circled portion of the speaker apparatus of FIG. 2;
FIG. 4 is an enlarged, partially broken-away plan view of the speaker apparatus of FIG. 1, illustrating the apparatus mounted on the head of the user; and
FIG. 5 is a pictorial view of the lower left hand quarter portion of the supporting structure of the speaker apparatus of FIG. 1 illustrating it without the speaker units or other internal operating parts mounted in place.
Referring now to the drawings, and more particularly to FIGS. 1 and 4 thereof, there is shown a speaker apparatus 10 in the form of a headphone assembly and constructed in accordance with the present invention. The speaker assembly 10 is adapted to be worn on the head H of a user. The assembly 10 generally comprises a U-shaped member 16 comprised of soft flexible material, such as polyurethane, and having a pair of parallel spaced-apart legs 18 and 20 joined integrally together at their rear-end portions by a rear head engaging transverse portion 22 to engage the head H of the user with the inside surfaces of the legs 18 and 20 engaging the ears E, as shown in FIG. 4. The legs 18 and 20 include a pair of chambers 24 and 25, respectively, which include openings 26 and 27 facing one another for receiving the ears E of the user. A pair of left speaker units 28 and 31 are mounted within a pair of spaced-apart speaker cavities 33 and 35 opening into the chamber 24, and similarly a pair of right speakers 37 and 39 are mounted within a pair of spaced-apart speaker cavities 41 and 43 disposed within the right hand leg 20 opening into the right hand chamber 25. As hereinafter described in greater detail, the speaker units are wired together to the cable connectors 12 and 14 for the purpose of interconnecting them with a suitable sound reproduction system (not shown) for energizing the speaker units. The front speakers 28 and 37 are positioned such that they are directed at an angle rearwardly generally, toward the ears E, and the rear speakers 31 and 39 are generally directed at an angle forwardly, slightly to the rear of the ears E. A pair of baffles 45 and 47 are disposed within the respective chambers 24 and 25, and as best shown in FIG. 4, the baffles 45 and 47 impede the sound emanating from the rear speakers 31 and 39 so that the sound traveling therefrom must move around the baffles 45 and 47, respectively, to contact the ears E of the user, whereby the sounds from the rear speakers are out of phase with the respective sounds from the front speakers 28 and 37 to help produce the desired quadraphonic phenomenon. In order to reduce the effective sound pressure levels at the ear from the front speakers to equalize the sound pressure levels from the rear speakers, the front portions 49 and 50 of the respective baffles 45 and 47 partially cover and thus block portions of the respective front speakers 28 and 37 for effectively reducing the sound pressure levels therefrom. Moreover, it has been found that the sound pressure levels from the rear speakers 31 and 39 should also be reduced by a similar lesser extent by having rear portions 52 and 54 of the respective baffles 45 and 47 block the speakers 31 and 39, respectively. It has been found that with the preferred embodiment of the present invention the front portions of the baffles 45 and 47 should block between 30 percent and 40 percent, and preferably about 35 percent, of the front speakers 28 and 37, and the rear portions 52 and 54 of the baffles 45 and 47 should block between 15 percent and 25 percent, and preferably about 20 percent, of the rear respective speakers 31 and 39.
A bleeder tube 56 connects the two chambers 24 and 25 in fluid communication to serve as a tuned port for the two-way transfer of sound between the chambers 24 and 25 for the purpose of equalizing sound pressures between the chambers and to provide a more natural and realistic phase relationship. The length and diameter of the tube may be adjusted for the most desirable effect for a given unit. The tube 56 has one of its ends extending within the chamber 24 opposite the ear E and extends from the leg portion 18, through the back transverse portion 22 to the leg 20 and into the chamber 25 as hereinafter described in greater detail.
While the speaker apparatus 10 is disclosed as being preferably in the form of a headphone assembly adapted to be mounted on the head of the user in the manner as shown and described, it is to be understood that the speaker apparatus of the present invention may also be employed in other types and kinds of headphone assemblies and also other types and kinds of speaker apparatus adapted to be used by the user in close proximity to the ears, such, for example, as a speaker system arranged in a headrest of a chair or within the back portion of a specially contoured shaped chair. Also, if desired, the apparatus 10 may be covered with fabric material (not shown) to provide a more pleasing appearance.
Considering now the apparatus 10 of the present invention in greater detail with reference to FIGS. 2, 3 and 4 of the drawings, the U-shaped block 16 is composed of four similarly shaped blocks of resilient foam plastic material comprising an L-shaped upper left block 56A, an L-shaped lower left block 58, a similar L-shaped upper right block 61 and a similar L-shaped lower right block 63, the quarter portions being fixed together by any suitable means, such as an adhesive. A closed loop bead 65 surrounding the opening 26 to the cavity 24 within the leg 18 as shown in FIG. 2 enables the cavity 24 to be sealed to the head of the user surrounding his ear E, it being understood that a similar bead (not shown) is disposed about the opening to the cavity 25.
Considering now the lower left hand block 58 as shown in FIG. 5, only one of the quarter block portions will now be considered in detail, it being understood that the remaining quarter portions being substantially identical thereto. The leg portion 18 of the block 58 has the lower half portion hollowed out to form the chamber 24, and the block 58 includes the lower half portions of the cavities 33 and 35 which have openings 67 and 69, which are U-shaped and which cooperate with similar shaped openings in the upper block portion to define the opening for the speakers 28 and 31. A pair of shoulders 70 and 72 for the cavity 33 and a pair of shoulders 74 and 76 for the cavity 35 retain the mounting flange of the speakers 28 and 31 within the respective cavities when they cooperate with similar shoulders for the upper quarter block portion of the block 16. It should be understood that if desired, a protective grille plate may be interposed between the face of the speakers and the shoulder 74 and 76.
In accordance with the present invention, the lower half portion of the baffle 45 projects away from the cavities 33 and 35 toward the opening 26 to the chamber 24. The baffle 45 is in the form of a triangular-shaped block with a larger face 49 extending from the opening 67, and having a smaller face extending transversely to the face 49 and extending from the opening 69 to the cavity 35. The opening 67 of the cavity 33 is directed toward the ear E of the user to as great an extent as possible for the particular mounting support, and the opening 69 of the cavity 35 is directed forwardly at an angle with the front rear face 52 of the baffle 49 preventing direct contact of the second waves emanating from the speaker 31 so that a phase delay is created relative to the front speaker 28, whereby the quadraphonic sensation is realized to the greatest extent possible without the necessity of electronically modifying the phase and separation requirements.
A circular cross-sectional recess 78 at the outer portion of the cavity 33 and a circular cross-sectional recess 81 at the outer portion of the cavity 35 is adapted to receive magnet cups of the speakers 28 and 31, respectively, it being understood that the recesses 78 and 81 cooperate with corresponding complementary-shaped recesses of the upper quarter block 56 and it being further understood that similar such recesses are provided in the other two quarter blocks 61 and 63.
In order to facilitate the attaching of the speaker apparatus 10 to the head of the user, a groove 83 receives a C-shaped band 85 which is composed of resilient stiff material, such as tempered steel, and a groove 87 in the upper portion of the block 16 receives a similar C-shaped bank 89 as shown in FIG. 3. The end portions of the steel bands 85 and 89 may be protected with a plastic coating or tape material (not shown) to prevent damage to the polyurethane material. The grooves 83 and 87 as shown in FIG. 3 cooperate with one another and are aligned to permit the tube 56 to be disposed therewithin between the two bands as well as certain lead wires for the speaker units.
Considering now the wiring of the speakers, a pair of cables 90 and 91 electrically connected to the terminals 12 and 14 are disposed within the groove 94 which opens outwardly to permit the cables to extend from the apparatus 10, the cable 90 extending from the groove 94 within a groove 90 to the speaker cavity 33. Two of the three conductor wires extending from the cable 96 are electrically connected to the speaker 28 for energizing it, and one of those two wires together with a third wire from the cable 90 extend backwardly therefrom within the groove 96 and the groove 94 to the groove 85 so that those two wires may extend to a groove 97 and a groove 99 within the quarter lower block 63 to enter the cavity 41 and to be electrically connected to the speaker 37. The cable 91 extends from the groove 94 within a groove 101 to the cavity 35, so that two of its wires may be electrically connected to the speaker 31 and one of those wires, together with a third wire from the cable 91, extend within a groove 103 to the groove 83, whereby the two wires extend to a groove 105 within the lower block 63 of the right hand portion of the block 16 and thus enter the cavity 43 to electfically connect to the speaker 39.
Various changes and modifications may be made in the particular embodiment disclosed, without departing from the spirit and scope of the invention as intended to be set forth in the appended claims, for example, the front and rear speakers of each chamber may be positioned at various different angles relative to the ears of the listener, but they should be positioned such that the directions of sound emanating therefrom are inclined toward one another to provide the desired interaction and are not parallel to or diverging away from one another.
Four channel stereo headphones have been employed to reproduce four channels of sound by providing two pairs of closely-spaced speakers adapted to be secured to the head of the user in close proximity to the ears in a manner somewhat similar to conventional headphones having only two speakers, one for each ear. However, while such four channel headphones having relatively closely spaced speakers have been successful in reproducing four channels of sound, they have not been entirely satisfactory for some applications in that they have not successfully reproduced quadraphonic sensations to a listener as compared to relatively widely spaced-apart speakers, since such speaker systems very closely approximate the acoustic effect present in an actual concert hall or elsewhere where the original sounds are reflected by walls, ceiling, floor and other objects within the room and converge upon the listener's ears with randomly varying time delays. Thus, it would be highly desirable to have a closely-spaced speaker apparatus which would reproduce four channels of sound in such a manner that it closely approximates the sound produced by four speakers spaced apart by a relatively great distance, and would provide an effect of "presence" to the listener as if he were actually present at the live performance of the original sound, the speaker apparatus being in the form of headphones or other apparatus adapted to be used in relatively close proximity to the ears of the user.
Therefore, the principal object of the present invention is to provide a new and improved speaker assembly adapted to be used in close proximity to the ears of the user and adapted to reproduce four channels of sound from a sound reproduction system in a realistic quadraphonic manner.
Briefly, the above and further objects are realized in accordance with the present invention by providing a new and improved speaker apparatus, adapted to be coupled electrically to a sound reproducing system, which includes a first and second pair of oppositely-disposed spaced-apart members each having respective first and second chambers opening substantially toward one another, a first pair of spaced-apart speaker cavities opening into the first chamber, a second pair of spaced-part speaker cavities opening into the second chamber, a first pair of speaker units mounted within the first pair of cavities and positioned generally facing the second chamber, a second pair of speaker units mounted within the second pair of cavities and positioned generally facing the first chamber, and a pair of first and second baffle members mounted at least partially within the first and second chambers, respectively, the first baffle member being disposed between one of the first pair of cavities and the opening of the first chamber, the second baffle member being disposed between one of the second pair of cavities and the opening of the second chamber so that when the system producing the sounds energizes the speakers, the sound emanating from the speaker units of each of the pairs of units is caused to be out of phase with one another at the opening to the chambers. As a result, when a user positions his head between the first and second pair of oppositely-disposed members and when the sound reproducing system energizes the speaker units, the user experiences a psychoacoustic quadraphonic sensation in that the four speakers of the apparatus of the present invention are physically spaced apart and the pairs of speakers on each side of the head of the user are physically arranged to produce sounds which are out of phase with one another. The baffle members of the present invention partially block one of the first and second pairs of cavities to control the effective sound pressure level at the openings of the chambers from the other one of the speaker units to equalize the sound pressure levels between the two speaker units on either side of the head of the user. A bleeder tube connects the two chambers in fluid communication to equalize the sound pressure levels of both chambers to approximate further the actual psychoacoustic phenomena occurring naturally and to provide the necessary phase relationship between the speakers.
Other objects and advantages of the present invention will become apparent from a reading of the following detailed description and the accompanying sheets of drawings, wherein:
FIG. 1 is a pictorial view of speaker apparatus which is adapted to be used with a sound reproduction (not shown), and which is constructed in accordance with the present invention;
FIG. 2 is an enlarged cross-sectional view of the speaker apparatus of FIG. 1 taken substantially along the line 2--2 thereof; FIG. 3 is an enlarged detailed view of the circled portion of the speaker apparatus of FIG. 2;
FIG. 4 is an enlarged, partially broken-away plan view of the speaker apparatus of FIG. 1, illustrating the apparatus mounted on the head of the user; and
FIG. 5 is a pictorial view of the lower left hand quarter portion of the supporting structure of the speaker apparatus of FIG. 1 illustrating it without the speaker units or other internal operating parts mounted in place.
Referring now to the drawings, and more particularly to FIGS. 1 and 4 thereof, there is shown a speaker apparatus 10 in the form of a headphone assembly and constructed in accordance with the present invention. The speaker assembly 10 is adapted to be worn on the head H of a user. The assembly 10 generally comprises a U-shaped member 16 comprised of soft flexible material, such as polyurethane, and having a pair of parallel spaced-apart legs 18 and 20 joined integrally together at their rear-end portions by a rear head engaging transverse portion 22 to engage the head H of the user with the inside surfaces of the legs 18 and 20 engaging the ears E, as shown in FIG. 4. The legs 18 and 20 include a pair of chambers 24 and 25, respectively, which include openings 26 and 27 facing one another for receiving the ears E of the user. A pair of left speaker units 28 and 31 are mounted within a pair of spaced-apart speaker cavities 33 and 35 opening into the chamber 24, and similarly a pair of right speakers 37 and 39 are mounted within a pair of spaced-apart speaker cavities 41 and 43 disposed within the right hand leg 20 opening into the right hand chamber 25. As hereinafter described in greater detail, the speaker units are wired together to the cable connectors 12 and 14 for the purpose of interconnecting them with a suitable sound reproduction system (not shown) for energizing the speaker units. The front speakers 28 and 37 are positioned such that they are directed at an angle rearwardly generally, toward the ears E, and the rear speakers 31 and 39 are generally directed at an angle forwardly, slightly to the rear of the ears E. A pair of baffles 45 and 47 are disposed within the respective chambers 24 and 25, and as best shown in FIG. 4, the baffles 45 and 47 impede the sound emanating from the rear speakers 31 and 39 so that the sound traveling therefrom must move around the baffles 45 and 47, respectively, to contact the ears E of the user, whereby the sounds from the rear speakers are out of phase with the respective sounds from the front speakers 28 and 37 to help produce the desired quadraphonic phenomenon. In order to reduce the effective sound pressure levels at the ear from the front speakers to equalize the sound pressure levels from the rear speakers, the front portions 49 and 50 of the respective baffles 45 and 47 partially cover and thus block portions of the respective front speakers 28 and 37 for effectively reducing the sound pressure levels therefrom. Moreover, it has been found that the sound pressure levels from the rear speakers 31 and 39 should also be reduced by a similar lesser extent by having rear portions 52 and 54 of the respective baffles 45 and 47 block the speakers 31 and 39, respectively. It has been found that with the preferred embodiment of the present invention the front portions of the baffles 45 and 47 should block between 30 percent and 40 percent, and preferably about 35 percent, of the front speakers 28 and 37, and the rear portions 52 and 54 of the baffles 45 and 47 should block between 15 percent and 25 percent, and preferably about 20 percent, of the rear respective speakers 31 and 39.
A bleeder tube 56 connects the two chambers 24 and 25 in fluid communication to serve as a tuned port for the two-way transfer of sound between the chambers 24 and 25 for the purpose of equalizing sound pressures between the chambers and to provide a more natural and realistic phase relationship. The length and diameter of the tube may be adjusted for the most desirable effect for a given unit. The tube 56 has one of its ends extending within the chamber 24 opposite the ear E and extends from the leg portion 18, through the back transverse portion 22 to the leg 20 and into the chamber 25 as hereinafter described in greater detail.
While the speaker apparatus 10 is disclosed as being preferably in the form of a headphone assembly adapted to be mounted on the head of the user in the manner as shown and described, it is to be understood that the speaker apparatus of the present invention may also be employed in other types and kinds of headphone assemblies and also other types and kinds of speaker apparatus adapted to be used by the user in close proximity to the ears, such, for example, as a speaker system arranged in a headrest of a chair or within the back portion of a specially contoured shaped chair. Also, if desired, the apparatus 10 may be covered with fabric material (not shown) to provide a more pleasing appearance.
Considering now the apparatus 10 of the present invention in greater detail with reference to FIGS. 2, 3 and 4 of the drawings, the U-shaped block 16 is composed of four similarly shaped blocks of resilient foam plastic material comprising an L-shaped upper left block 56A, an L-shaped lower left block 58, a similar L-shaped upper right block 61 and a similar L-shaped lower right block 63, the quarter portions being fixed together by any suitable means, such as an adhesive. A closed loop bead 65 surrounding the opening 26 to the cavity 24 within the leg 18 as shown in FIG. 2 enables the cavity 24 to be sealed to the head of the user surrounding his ear E, it being understood that a similar bead (not shown) is disposed about the opening to the cavity 25.
Considering now the lower left hand block 58 as shown in FIG. 5, only one of the quarter block portions will now be considered in detail, it being understood that the remaining quarter portions being substantially identical thereto. The leg portion 18 of the block 58 has the lower half portion hollowed out to form the chamber 24, and the block 58 includes the lower half portions of the cavities 33 and 35 which have openings 67 and 69, which are U-shaped and which cooperate with similar shaped openings in the upper block portion to define the opening for the speakers 28 and 31. A pair of shoulders 70 and 72 for the cavity 33 and a pair of shoulders 74 and 76 for the cavity 35 retain the mounting flange of the speakers 28 and 31 within the respective cavities when they cooperate with similar shoulders for the upper quarter block portion of the block 16. It should be understood that if desired, a protective grille plate may be interposed between the face of the speakers and the shoulder 74 and 76.
In accordance with the present invention, the lower half portion of the baffle 45 projects away from the cavities 33 and 35 toward the opening 26 to the chamber 24. The baffle 45 is in the form of a triangular-shaped block with a larger face 49 extending from the opening 67, and having a smaller face extending transversely to the face 49 and extending from the opening 69 to the cavity 35. The opening 67 of the cavity 33 is directed toward the ear E of the user to as great an extent as possible for the particular mounting support, and the opening 69 of the cavity 35 is directed forwardly at an angle with the front rear face 52 of the baffle 49 preventing direct contact of the second waves emanating from the speaker 31 so that a phase delay is created relative to the front speaker 28, whereby the quadraphonic sensation is realized to the greatest extent possible without the necessity of electronically modifying the phase and separation requirements.
A circular cross-sectional recess 78 at the outer portion of the cavity 33 and a circular cross-sectional recess 81 at the outer portion of the cavity 35 is adapted to receive magnet cups of the speakers 28 and 31, respectively, it being understood that the recesses 78 and 81 cooperate with corresponding complementary-shaped recesses of the upper quarter block 56 and it being further understood that similar such recesses are provided in the other two quarter blocks 61 and 63.
In order to facilitate the attaching of the speaker apparatus 10 to the head of the user, a groove 83 receives a C-shaped band 85 which is composed of resilient stiff material, such as tempered steel, and a groove 87 in the upper portion of the block 16 receives a similar C-shaped bank 89 as shown in FIG. 3. The end portions of the steel bands 85 and 89 may be protected with a plastic coating or tape material (not shown) to prevent damage to the polyurethane material. The grooves 83 and 87 as shown in FIG. 3 cooperate with one another and are aligned to permit the tube 56 to be disposed therewithin between the two bands as well as certain lead wires for the speaker units.
Considering now the wiring of the speakers, a pair of cables 90 and 91 electrically connected to the terminals 12 and 14 are disposed within the groove 94 which opens outwardly to permit the cables to extend from the apparatus 10, the cable 90 extending from the groove 94 within a groove 90 to the speaker cavity 33. Two of the three conductor wires extending from the cable 96 are electrically connected to the speaker 28 for energizing it, and one of those two wires together with a third wire from the cable 90 extend backwardly therefrom within the groove 96 and the groove 94 to the groove 85 so that those two wires may extend to a groove 97 and a groove 99 within the quarter lower block 63 to enter the cavity 41 and to be electrically connected to the speaker 37. The cable 91 extends from the groove 94 within a groove 101 to the cavity 35, so that two of its wires may be electrically connected to the speaker 31 and one of those wires, together with a third wire from the cable 91, extend within a groove 103 to the groove 83, whereby the two wires extend to a groove 105 within the lower block 63 of the right hand portion of the block 16 and thus enter the cavity 43 to electfically connect to the speaker 39.
Various changes and modifications may be made in the particular embodiment disclosed, without departing from the spirit and scope of the invention as intended to be set forth in the appended claims, for example, the front and rear speakers of each chamber may be positioned at various different angles relative to the ears of the listener, but they should be positioned such that the directions of sound emanating therefrom are inclined toward one another to provide the desired interaction and are not parallel to or diverging away from one another.