Earphone Assembly

Abstract

An earphone assembly is provided of the pneumatic type such as are presently used on aircraft, and which is constructed to improve the reproduction quality of the instrument by providing high frequency transducers directly at the ear pieces for producing high frequency sound signals which would otherwise be attenuated in the flexible plastic tubes coupling the ear pieces to the main electrical/acoustical transducer.

Parent Case Text

This application is a continuation-in-part of copending application Ser. No. 64,484 filed for Robert Ryder on Aug. 17, 1970, and entitled "EARPHONE ASSEMBLY," now abandoned.

Description

BACKGROUND OF THE INVENTION

In the sound reproducing systems used in present day aircraft, it is usual to install an electro/acoustical transducer at each seat. Earphones are provided for the individual passengers, and these are plugged into sockets in the corresponding transducers. The earphones comprise simply a pair of acoustical ear pieces, and flexible plastic tubes extending from the ear pieces to a tubular plug assembly which may be plugged directly into the aforesaid transducer. In this way the sound signals produced by the transducer are carried through the plastic tubes to the ear pieces, and into the ears of the passenger wearing the earphone assembly.

It has been found, however, that the higher frequency sounds are attenuated in the aforesaid flexible plastic tubes, and the quality of the sound reproduction by the prior art systems of the aforesaid type is somewhat impaired. This situation is corrected by the system of the present invention, in which small high frequency electro/acoustical transducers are mounted directly adjacent the ear pieces and are electrically connected to the electrical audio signal source, so that the higher frequency sounds are not lost and high fidelity reproduction may be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representation of an earphone assembly constructed in accordance with one embodiment of the invention and which plugs, for example, into an electro/acoustical transducer mounted in the arm of an aircraft seat;

FIG. 2 is an enlarged view of an appropriate plug used by the assembly of FIG. 1;

FIG. 3 is a plan view of the plug of FIG. 2, taken along the line 3--3 of FIG. 2;

FIG. 4 is a somewhat schematic representation of a section of one of the ear piece units of FIG. 1, and taken essentially along the line 4--4 of FIG. 1;

FIG. 5 is a schematic functional diagram of the system of FIG. 1;

FIG. 6 is a representation of an earphone assembly constructed in accordance with a second embodiment of the invention; and

FIG. 7 is a schematic diagram of the electro/acoustical system associated with the earphone assembly of FIG. 6.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

As shown in the drawings, a first electro/acoustical transducer 10 is mounted, for example, in the arm of an aircraft seat 12, and the transducer 10 includes a socket which receives, for example, a dual plug assembly 14. The dual plug assembly 14, as shown in FIGS. 2 and 3, for example, includes a first pair of tubular plugs 16 and 18 which extends into appropriate sockets in the transducer 10, so as to introduce the corresponding sound signals into a pair of flexible plastic tubes 20 and 22, the plastic tubes extending to a pair of acoustical ear pieces 24 and 26.

The system illustrated in the drawings, as is usual with most systems used in present day installations, is a stereo type of system so that two tubes 20 and 22 and two separate plugs 16 and 18, are provided for carrying the stereo sound signals to the ear pieces 24 and 26.

As mentioned above, it has been found that the higher frequency sound signals are attenuated in the tubes 20 and 22. For that reason, the present invention provides for small high frequency electro-acoustical transducers 30 and 32 to be mounted directly on the respective ear pieces 24 and 26. Electric wires, such as the wires 34, which carry electric current to the transducers 30 and 32 are connected to the transducers, and these wires may be imbedded in the walls of the tubes 20 and 22 to extend along the tubes to the plug 14. The plug 14 also includes, for example, an electric plug 36 to which the wires are connected. For the usual stereo system, three wires are used, and they are connected to the transducers 30 and 32 so that stereo signals may be produced by the high frequency transduers.

The transducers 30 and 32 may be of any appropriate type and, as shown in FIG. 4, for example, the ear piece 24 may include a housing defining an acoustical chamber 24a, the tube 22 being coupled to the interior of the acoustical chamber, so that the sound signals may be passed into the chamber and through the section 24b which is designated to fit into the ear of the wearer. The high frequency transducer 30, for example, is mounted adjacent the acoustical chamber 24a, and it includes a conventional crystal transducer 38 energized through wires 34. In this way, the transducer 3o produces high frequency sound signals which pass into the acoustical chamber 24a, and which are combined with the sound signals from the tube 22, in order to compensate for any attenuation of the high frequency sound signals in the tube 22. It will be understood, of course, that the ear piece 26 and transducer 32 are similarly constructed.

For satisfactory high fidelity reception, it is important that the ear pieces 24 and 26 be maintained in alignment with the ear canals of the listener, which means that the ear pieces should be held substantially on a horizontal axis regardless of the head width of the listener. An adjustment is provided in the earphone assembly of FIG. 1, so that this criteria may be met for various head sizes.

In the illustrated embodiment, the ear pieces 24 and 26 are supported by a pair of elongated resilient members 40 and 42 each of which, for example, may comprise a resilient wire composed, for example, of steel, and surrounded by an appropriate tubular member which may, for example, be composed of polyvinylchloride. The free ends of the members 40 and 42 are mounted, for example, on a rack and pinion assembly 44, or its equivalent.

An adjustment knob 44a is provided, and it may be turned to move the rack 44b in and out of the assembly, so as to adjust the distance between the ear pieces 24 and 26, and to adjust the ear pieces to different head sizes. As mentioned above, the rack and pinion assembly 44 may be replaced by any equivalent adjustment, such as a lead screw, or the like.

It will be appreciated from a consideration of FIGS. 2 and 3, for example, that the plug 14 has a right angle bend formed in its body portion. This is advantageous in that it provides a polarizing control for the plugs 16 and 18, and assures that the plugs will be plugged into the proper sockets in the transducer 10, so that the proper sounds will be carried to the proper ears for the correct stereo sound effect. The electric plug 36 may be part of the same plug as the plugs 16 and 18, as shown in FIGS. 2 and 3, so that all the plugs may be inserted as a unit into the corresponding sockets in the transducer 10. The ear pieces 24 and 26 need not necessarily be of such configuration that they penetrate the ear cavity or canal. They may assume, for example, the form of ear muffs in which the sound channels enter from diverse angles.

In the system of FIG. 5, the stereo electrical input is amplified in separate amplifiers 50 and 52. The amplifiers are connected through corresponding volume controls 54 and 56 to the low frequency transducers designated 10a and 10b in FIG. 5. The volume controls 54 and 56 may be mechanically intercoupled so that a single control may be used to adjust the volume of the two stereo signals. As illustrated in FIG. 5, the tubes 20 and 22 intercouple the transducers 10a and 10b to the respective ear pieces 24 and 26, whereas wires 34 extend to the respective high frequency transducers 30 and 32.

The response of the transducers 10a and 10b may be substantially uniform throughout the entire audio range, and the response of the high frequency transducers 30 and 32 may be such that they compensate for the resulting attenuation of the higher frequency sound signals in the tubes 20 and 22. It is also appropriate to design the transducers 10a and 10b to respond only to the low frequency part of the audio signal range, so that only the lower frequency sound signals are produced by the transducers 10a and 10b, since these are the signals which may be appropriately carried by the tubes 20 and 22. Then, the high frequency transducers 30 and 32 are controlled so that all the higher frequency sound signals are produced only by the latter transducer.

Since the transducers 30 and 32 are only required to produce the higher frequency sound signals, these transducers may be small and light, and also they may be inexpensive. Therefore, the high frequency transducers may be conveniently mounted directly on the ear pieces without adding materially to the cost or weight of the earphone assembly. The resulting assembly, including the adjustment means described above, may be comfortably supported in the ears of the listener, and it provides for an ideal high fidelity sound reproducing system.

In the assembly of FIG. 6 the ear pieces 24 and 26 are mounted on the ends of respective plastic elongated support brackets 50 and 52, each of which has a generally arcuate shape, the support brackets being hinged by a suitable hinge member 54. The hinge member 54 holds the brackets 50 and 52 in a relatively tight frictional engagement, so that they may be opened or closed to suit various head sizes of the users, and to cause the assembly to be firmly held on the head of the user.

The assembly of FIG. 6, in addition to the high frequency transducers 30 and 32, also includes a second pair of high frequency transducers 31 and 33 which are also mounted on the respective ear pieces 24 and 26, as shown. As shown in FIG. 6, the transducer 31 is coupled into the acoustical chamber of the ear piece 24 at an angle with respect to the transducer 30. Likewise, the transducer 33 is coupled into the acoustical chamber of the ear piece 26 at an angle with respect to the transducer 32. This angular relationship between the transducers 30 and 31 and between the transducers 32 and 33, changes the character of the high frequency sound signals entering the respective acoustical chambers, since those from the transducers 31 and 33 effectively have to "bend around a corner" when entering the acoustical chamber. This relationship simulates the reflection of sound from the walls, for example, of an auditorium, so that a person using the assembly of FIG. 6 actually has the sensation of listening to a concert in full high fidelity range, and seated, for example, in an auditorium.

The assembly of FIG. 6 is intended to be used in conjunction with a four-channel stereo sound system. For that reason, a first tube 56 (tube "A") is coupled to the ear piece 24, and a second tube 58 (tube "B") is coupled to the ear piece 26. The tubes 56 and 58 correspond to the flexible plastic tubes 20 and 22 of the embodiment of FIG. 1. In the case of the assembly of FIG. 6, the tube 56 carries the low frequency sound signals from two of the stereo sources to the ear piece 24, whereas the tube 58 carries the low frequency sound signals from the remaining two stereo sources to the ear piece 26.

The high frequency sound components from one of the stereo sources are produced, as before, by the transducer 30, whereas the high frequency sound signals from the second stereo source are produced, as before, by the transducer 32. The transducer 31 reproduces the high frequency sound signals from the third stereo source, whereas the transducer 33 reproduces the high frequency sound signals from the remaining stereo source.

The transducer 30 is activated by wires 60, and the transducer 32 is activated by wires 62. The wires 60 and 62 are carried, for example, in a flexible plastic tube 64 (tube "C"). The transducer 31 is activated by wires 66, whereas the transducer 33 is activated by wires 68. The wires 66 and 68 are carried, for example, in a flexible plastic tube 70 (tube "D").

A portion of a four-channel stereo system for operation in conjunction with the assembly of FIG. 6 is shown schematically in FIG. 7. As shown in FIG. 7, the stereo electrical input signals from the first and second stereo sources are applied to a block 100, whereas the electrical signals from the third and fourth stereo sources are applied to a block 102. The blocks 100 and 102 contain appropriate low frequency transducers, such as described above, so that the low frequency sound signals corresponding to the various stereo sources may be obtained. The low frequency sound signals from the first stereo source are carried in a tube 104, whereas the low frequency stereo signals from the second stereo source are carried in a tube 106.

The tubes 104 and 106 are plugged into the low frequency transducers by means of a plug 109. The low frequency sound signals from the third stereo source are carried by a tube 108 which, as shown, is coupled into the tube 104, whereas the low frequency sound signals from the fourth stereo source are carried by a tube 110 which, as shown, is coupled into the tube 106. The combined tubes 104 and 108 are coupled through a bleed valve 120 and through a tube 122 into a socket 124, whereas the combined tubes 106 and 110 are coupled through the bleed valve 120 to a tube 126 which, likewise, is coupled into the socket 124.

Therefore, the tube 122 carries the low frequency sound signals from the first and third stereo sources, whereas the tube 126 carries the low frequency sound signals from the second and fourth stereo sources. The tubes 56 and 58 are plugged into the socket 124 by means, for example, of a plug 130. When so coupled, the tube 56 carries the low frequency sound signals from the first and third stereo sources to the ear piece 24, whereas the tube 58 carries the low frequency sound signals from the second and fourth sources to the ear piece 26.

The electrical inputs from the first and second stereo sources are also carried, by way of a plug 132 to the wires 60 and 62 respectively. The wires 60 carry the electric signals from the first source to the high frequency transducer 30, whereas the wires 62 carry the electric signals from the second source to the high frequency transducer 32. Likewise, the electrical signals from the third and fourth stereo sources are carried by way of a plug 134 to the wires 66 and 68. In this way, the wires 66 carry the electric signals from the third stereo source to the high frequency transducer 31, whereas the wires 68 carry the electric signals from the fourth source to the high frequency transducer 33.

The bleed valve 120 has a control 120a which may be turned to cause an intermixing of the low frequency sound signals in the tubes, so that various blending effects may be achieved, if so desired. With the system described above, a desired blending of all the low frequency sounds may be achieved by setting the control 120a of the bleed valve 120. Also, an "auditorium" effect is achieved with respect to the high frequency sounds from the third and fourth sources, by virtue of the positioning of the respective high frequency transducers 31 and 33 with respect to the respective acoustic chambers 24a and 26a.

It is apparent that although particular embodiments of the invention have been shown and described, modifications may be made. It is intended in the following claims to cover all modifications that fall within the spirit and scope of the invention.

Claims

What is claimed is:

1. An earphone assembly including:

a first ear piece defining a first acoustic chamber and a second ear piece defining a second acoustic chamber;

a first electrical/acoustical transducer for producing sound signals in response to audio electrical signals applied thereto;

a first tubular member intercoupling said first transducer to said first acoustic chamber for carrying the sound signals from said first transducer to said first ear piece;

a second electrical/acoustical transducer for producing sound signals in response to audio electrical signals applied thereto;

a second tubular member intercoupling said second transducer to said second acoustic chamber for carrying the sound signals from said second transducer to said second ear piece; and

a bleed valve member intercoupling said first and second tubular members and adjustable to produce an intermixing between the sound signals in said first and second tubular members.

2. An earphone assembly including: a first ear piece defining a first acoustic chamber and a second ear piece defining a second acoustic chamber; a first electrical/acoustical transducer for producing sound signals in response to audio electrical signals derived from a first signal source and applied thereto; a first tubular member intercoupling said first transducer to said first acoustic chamber for carrying relatively low frequency sound signals from said first transducer to said first ear piece; a second electrical/acoustical transducer for producing sound signals in response to audio electrical signals derived from a second signal source and applied thereto; a second tubular member intercoupling said second transducer to said second acoustic chamber for carrying relatively low frequency sound signals from said second transducer to said second ear piece; a first high frequency electrical/acoustical transducer mounted on said first ear piece for introducing relatively high frequency sound signal into said first acoustic chamber along a predetermined axis in response to applied audio electrical signals; a second high frequency electrical/acoustical transducer mounted on said second ear piece for introducing relatively high frequency sound signals into said second acoustic chamber along a predetermined axis in response to applied audio electrical signals; circuit means for introducing the audio electrical signals from said first signal source to said first high frequency transducer; and circuit means for introducing the audio electrical signals from said second signal source to said second high frequency transducer.

3. The assembly defined in claim 2, and which includes a third high frequency electrical/acoustical transducer mounted on said first ear piece for introducing relatively high frequency sound signals into said first acoustic chamber in response to audio electrical signals applied thereto; circuit means connecting said third high frequency transducer to a third signal source for introducing audio signals from said third signal source to said third high frequency transducer; a fourth high frequency electrical/acoustical transducer mounted on said second ear piece for introducing relatively high frequency sound signals into said second acoustic chamber in response to audio electrical signals applied thereto; and circuitry connecting said fourth high frequency transducer to a fourth signal source for introducing the audio electrical signals from said fourth signal source to said fourth high frequency transducer.

4. The assembly defined in claim 3, in which said first and third high frequency transducers introduce sound signals into said first acoustic chamber along respective axes displaced angularly from one another, and in which said second and fourth high frequency transducers introduce sound signals into said second acoustic chamber along respective axes angularly displaced from one another.

5. The assembly defined in claim 2, and which includes resilient elongated means interconnecting said ear pieces to position said ear pieces in the ears of the listener.

6. The assembly defined in claim 5, and which includes mechanically adjustable means interposed in said resilient means for adjusting the distance between said ear pieces to different head sizes.