MULTI-CHANNEL HEADPHONE SYSTEM

Abstract: Multi-channel headphones capable of providing quality 3-dimensional (3-D) sound in an atmosphere of intimacy and privacy for individuals is provided. The multi-channel headphones include: at least two speaker units for each piece, for reproducing distinct sounds; at least two enclosures for receiving each of the at least two speaker units; a sound field generation member with an inner wall, the sound field generation member arranged such that it surrounds the listener's ear, for supporting the at least two enclosures, and creating an accoustic space for guiding the sounds from the enclosures into the listener's auricle; a sound adjustment plate having a series of slits by which the direct sounds emanating from the speaker units, and reflected sounds are adjusted, the sound adjustment plate mounted to cover the gap between the adjacent ends of the enclosures; and an auxiliary sound adjustment plate having a series of ribs to be fitted into the slits of the sound adjustment plate. The multi-channel headphones can solve the problems caused by the structural defects of existing headphones, so that interference of sounds due to increased loadness does not occur, and high-fidelity 3-D sound can be reproduced with realistic effects.

Description: MULTI-CHANNEL HEADPHONE SYSTEM Technical Field The present invention relates to multi-channel headphones for use in reproducing 3-dimensional (3-D) sounds in an atmosphere of intimacy and privacy for individuals, and more particularly, to multi-channel headphones whose constructions are improved to make them fit comfortably and to enhance the sound quality. Background Art The location of a sound source can be perceived by a difference in phase of acoustic waves as well as a difference in acoustic intensity sensed by a listener's ears. Existing stereo headphones include two separate sound source (speaker unit) for R- and L-channels, and thus they are suitable for giving the listener a sense of direction of a sound by the binaural effect. On the other hand, creation of a directional phantom image and a wide sound field for spatial characters are the essential aspects for a vivid 3-D sound reproduction. To meet these requirements, front and rear speaker units must be arranged at a great distance from each other around the listener. Unfortunately, it is not easy to accommodate a plurality of speaker units taking up such a large space within a pair of multi-channel headphones. Although a plurality of speaker units can be arranged within a single enclosure, direct sounds and reflected sounds interfere due to serious sound reflections within the narrow enclosure, thereby smearing the sounds. As a result, reproduction of clear original sounds from the sound sources is difficult. Considering that the ultimate goal of all acoustic systems is high-fidelity reproduction, such a reduced clearness may be regarded as a sort of sound distortion. In consideration of these problems, an application for open-type multichannel headphones in which a plurality of speaker units are mounted in separate enclosures have been filed by the present applicant and assigned Korean Patent Application No. 10-2000-0009578. Because each speaker unit is accommodated in a separate enclosure, discrete multi-channel sounds can be reproduced with accurate phase. In particular, each speaker unit is mounted in a corresponding enclosure as far away from the listener's ears as possible, and sound passageways are constructed within each enclosure to allow repeated reflection and diffraction of the sounds during transmission of the sounds into the listener's eardrums. As a result, a comparatively wide sound field that ensures that the listener perceives spatial character can be created bythe multi-channel headphones, like general large speaker systems. A disadvantage of the multi-channel headphones lies in that, due to poor front and rear sound field integration, the sounds emanating from the adjacent front and rear enclosures cannot be perceived as clear sounds. In particular, the phantom image cannot be created continuously and smoothly, so that the listener cannot experience enriched sounds with deep and wide spatial character. Unlike conventional stereo headphones, since the multi-channel headphones suggested by the present applicant include at least two speaker units for each ear piece, there is another problem in that the multi-channel headphones cannot comfortably fit over the listener's ears. Disclosure of the Invention To solve these problems, it is an object of the present invention to provide multi-channel headphones which can fit comfortably, and can deeply and widely expand the sound field. To achieve the object of the present invention, there is provided multichannel headphones comprising: at least two speaker units for each ear piece, for reproducing distinct sounds; at least two enclosures for receiving each of the at least two speaker units; and a sound field generation member with an inner wall, the sound field generation member arranged such that it surrounds the listener's ear, for supporting the at least two enclosures, and creating an acoustic space for guiding the sounds from the enclosures into the listener's auricle. It is preferable that a number of projections or a series of grooves for deflecting, scattering and diffracting sounds are formed in the inner wall of the sound field generation member, thereby expanding the sound field. It is preferable that the multi-channel headphones further comprise a sound adjustment plate to filter the sound distorted during transmission in the enclosures and to prevent fluctuation of sound waves. Brief Description of the Drawings FIG. 1 illustrates a preferred embodiment of a pair of multi-channel headphones according to the present invention, which are worn by a listener; FIG. 2 illustrates another preferred embodiment of multi-channel headphones according to the present invention; FIGS. 3A and 3B are perspective views illustrating the inner and outer sides of the multi-channel headphones of FIG. 2, respectively; FIG. 4 is a sectional view illustrating the configuration of the main parts of the multi-channel headphones shown in FIG. 2; and FIG. 5 is a sectional view illustrating another example of the sound field generation member of the multi-channel headphones of FIG. 2. Best mode for carrying out the Invention The present invention will now be described more fully with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. A preferred embodiment of multi-channel headphones according to the present invention is shown in FIG. 1. In FIG. 1 , only the left ear piece of the multi-channel headphones worn by a listener is illustrated. The right ear piece is engaged symmetrically with respect to the left ear piece on the right side of the listener's head with the same configuration as the left ear piece, and thus a description of the right ear piece will not provided here for convenience. Reference numerals 10 and 10' denote speaker units for reproducing sounds emanating from distinct channels, which are arranged spaced apart from each other in the front and rear of the listener's ear. Reference numerals 20 and 20' denote open-style enclosures for receiving the speaker units 10 and 10', respectively, and transferring the sounds from the speaker units 10 and 10' toward the listener's auricle. Reference numeral 30 denotes an annular sound field generation member serving as an acoustic space for making the sound field created during transmission through the enclosures 20 and 20' to expand. In particular, the speaker units 10 and 10' are mounted in the enclosures 20 and 20', respectively, such that the speaker units 10 and 10' are located far away from the listener's auricle. Although not illustrated, a sound guide plate and a plurality of guide ribs for scattering and diffracting the sounds during transmission from the speaker units 10 and 10' to the listener's auricle are mounted within each of the enclosures 20 and 20'. The constructions of the enclosures 20 and 20' are fully described in Korean Patent Application No. 10-2000-0009578, and thus descriptions thereof will not be provided here. Referring to FIG. 1 , the sound field generation member 30 has an annular shape such that it envelopes the listener's auricle. The acoustic space enclosed by the annular sound field generation member 30 serves to expand the sound field. The sound field generation member 30 may be formed in combination with the headband 40, or may be separately manufactured and then connected to the headband 40. The base of the sound field generation member 30 is shaped to rest stably on the listener's face, and the opposite side is open toward the ambient. The enclosures 20 and 20' are mounted on the open side of the sound field generation member 30. In the multi-channel headphones having the sound field generation member 30 according to the present invention, the sounds from the enclosures 20 and 20' are captured for a while within the acoustic space surrounded by the sound field generation member 30. At the same time the sounds are reflected more than one time by the inner wall 31 (See FIG. 4), thereby expanding the sound field. As a result, the listener can experience 3-D sounds with spatial character. In addition, a continuous transfer of the directional phantom image, which is successfully created within the enclosures 20 and 20' as described in the previous application, can be further ensured by the sound field generation member 30, thereby further improving spatial character in 3-D sound reproduction. Another embodiment of the multi-channel headphones is illustrated in FIG. 2. The same reference numerals as in FIG. 1 are used to designate the same elements as in FIG. 1. In FIG. 2, reference numerals 20 and 20' denote enclosures for receiving speaker units, respectively, and reference numeral 30' represents a sound field generation member modified from the sound field generation member 30 of FIG. 1. The enclosures 20 and 20' are mounted on the outer side of the sound field generation member 30', spaced apart from each other in the front and rear of the listener's ear. The sound adjustment plate 50 is mounted at the outside to cover the gap between the enclosures 20 and 20'. An auxiliary sound adjustment plate 60 is fitted to the sound adjustment plate 50 as needed, and a seal member 70 around the periphery wall of the sound field generation member 30'. The sound field generation member 30' of the present embodiment has an elliptical shape which is long in the lateral direction, such that the enclosures 20 and 20' are appropriately spaced apart from each other in the lateral direction. As shown in FIG. 4, the base of the sound field generation member 30' is curved such that it can fit comfortably over the listener's face. Irregular projections 32 are formed in the inner wall 31. The irregular projections 32 enhances a reverberant effect by reflecting, diffracting and dispersing the sounds. Alternatively, a plurality of grooves 33 can be regularly • formed in the inner wall 31 of the sound field generation member 30' to serve as a bandpass filter as well as to enhance the reverberant effect. The sound adjustment plate 50 is convex outwards, such that it covers the ends of the enclosures 20 and 20'. The sound adjustment plate 50 has a series of longitudinal slits 51 a constant distance spaced apart from each other. The sound adjustment plate 50 may formed as a separate member. It is preferable that the sound adjustment plate 50 is formed in combination with the headband 40, extending from the ends of the headband 40. The auxiliary sound adjustment plate 60 has a series of ribs 61 , which are projections corresponding to the slits 52 of the sound adjustment plate 50. The auxiliary sound adjustment plate 60 is optionally fitted into the sound adjustment plate 60 according to the listener's hearing ability or preference. The slits 51 of the sound adjustment plate 50 and the ribs 61 of the auxiliary sound adjustment plate 60 appropriately absorb and reflect the direct and reflected sounds emanating from the speaker units mounted in the enclosures 20 and 20' which are scattered or distorted due to the gap between the enclosures 20 and 20' arranged in the front and rear of the listener's ear, thereby enhancing spatial effect and sound localization without fluctuations of the sounds. In other words, the sound adjustment plate 50 and the auxiliary sound adjustment plate 60 allow a smooth and continuous moving of the directional phantom image from one speaker unit to the other speaker unit. As a result, the continuity and accurate focusing of the phantom image by the sound field generation member 30' are ensured, which enables the listener to aware the location of every instrument used for the performance as if he or she is sitting in a concert hall. The auxiliary sound adjustment plate 60 enables that the listener varies the depth of sounds, and is optionally adopted according to the listener's hearing ability or preference. The seal member 70 provided for a pleasant contact with the headphones, as in a general headphones assembly, is formed of a smooth material such as foam, textile or leather. The seal member 70 surrounds the peripheral wall of the sound field generation member 30(30') and extends the base and outer side of the sound field generation member 30(30'). In addition, the seal member 70 minimizes air leaking through the gap between the sound field generation member 30(30') and the listener's head, thereby absorbing unnecessary noise within the sound field generation member 30(30') and from the outside. Although not illustrated, the shapes of the sound field generation member 30(30') and the projections 32 or grooves 33 formed in the inner wall 31 , the arrangement of the enclosures 20 and 20' on the sound field generation member 30', and the configuration and shapes of the sound adjustment plate 50 and the auxiliary sound adjustment plate 60 can be varied in different forms according to the sound character, or the listener's hearing ability or preference. In the embodiments previously described, two speaker units are provided for each ear piece to reproduce 3-D sound. However, more than two speaker units can be arranged for high-fidelity 3-D sound reproduction. Industrial Applicability As previously described, in the multi-channel headphones according to the present invention, discrete speaker units for multi-channels are mounted in separate enclosures, which allows the listener to aware distinct sounds from the different channels with accurate phase. Due to the reflection and scattering of sound during transmission within the enclosures, high-quality sound can be produced with the essential phonic elements for 3-D sound reproduction, i.e, with the distinctness, spatial character caused by wide sound field, and directional phantom image. In addition, the sound field generation member, the sound adjustment member, and the auxiliary sound adjustment member further extend the sound field that is significant in perceiving the directional phantom image, thereby increasing spatial effects. The multi-channel headphones according to the present invention can solve the problems caused by the structural defects of the headphones, so that interference of sounds due to increased loadness does not occur, and high- fidelity 3-D sound can be reproduced as if the listener is sitting in a record room or a concert hall. The multi-channel headphones according to the present invention are designed to fit comfortably over the listener' head, rather than ears, in consideration of the multiple speaker units enclosed in separate enclosures, and the weight of the speaker units and enclosures. The configuration and design of the multi-channel headphones can be changed in a variety of forms.

Claims: What is claimed is: 1. Multi-channel headphones comprising: at least two speaker units for each ear piece, for reproducing distinct sounds; at least two enclosures for receiving each of the at least two speaker units; and a sound field generation member with an inner wall, the sound field generation member arranged such that it surrounds the listener's ear, for supporting the at least two enclosures, and creating an acoustic space for guiding the sounds from the enclosures into the listener's auricle. 2. The multi-channel headphones of claim 1 , wherein the adjacent ends of the enclosures supported by the sound field generation member are separated from each other, and the multi-channel headphones further comprise a sound adjustment plate having a series of slits by which the direct sounds emanating from the speaker units, and reflected sounds are adjusted, the sound adjustment plate mounted to cover the gap between the adjacent ends of the enclosures. 3. The multi-channel headphones of claim 2, further comprising an auxiliary sound adjustment plate having a series of ribs to be fitted into the slits of the sound adjustment plate, wherein the auxiliary sound adjustment plate is combined with the sound adjustment plate, or detached from the sound adjustment plate. 4. The multi-channel headphones of claim 1 or2, wherein a number of projections or a series of grooves for deflecting, scattering and diffracting sounds are formed in the inner wall of the sound field generation member. 5. The multi-channel headphones of claim 1 , further comprising a seal member for covering the periphery wall of the sound field generation member.

Inventors: KIM SUNG-IL, KIM, SUNG-IL
Applicants: KIM SUNG IL, MM GEAR CO LTD, KIM, SUNG-IL, MM GEAR CO., LTD.
Application year: 2000
Main classification: H04R1
IPC codes: H04R1, H04R5