CA1051350A - Headphone system - Google Patents
Headphone systemInfo
- Publication number
- CA1051350A CA1051350A CA242,592A CA242592A CA1051350A CA 1051350 A CA1051350 A CA 1051350A CA 242592 A CA242592 A CA 242592A CA 1051350 A CA1051350 A CA 1051350A
- Authority
- CA
- Canada
- Prior art keywords
- headphone
- channel
- signal source
- headphones
- cross
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04S—STEREOPHONIC SYSTEMS
- H04S1/00—Two-channel systems
- H04S1/002—Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution
- H04S1/005—For headphones
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Stereophonic System (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A headphone system for reproduction of 2-channel stereophonic signals recorded on a program source with a headphone. A part of each of the right and left channel stereophonic signals is respectively combined with the other channel stereophonic signal through a low pass filter with a cut-off frequency not greater than 400 Hz and an attentuation characteristic of -1.5 to -6 dB/oct and the combined stereo-phonic signals are applied to the headphone. As a result, it is possible to stimulate same acoustic environment with the headphone as that obtained by actually listening to sound waves radiated from two loudspeakers.
A headphone system for reproduction of 2-channel stereophonic signals recorded on a program source with a headphone. A part of each of the right and left channel stereophonic signals is respectively combined with the other channel stereophonic signal through a low pass filter with a cut-off frequency not greater than 400 Hz and an attentuation characteristic of -1.5 to -6 dB/oct and the combined stereo-phonic signals are applied to the headphone. As a result, it is possible to stimulate same acoustic environment with the headphone as that obtained by actually listening to sound waves radiated from two loudspeakers.
Description
The present invention relates to a headphone system for reproducing a 2-channel stereo signal recorded in a program source and listening to the reproduced signal through a head~
phone.
The invention provides a headphone system which enables an audiophile, when he merely connects a simple electric circuit between a reproducing system and a usual headphone, to obtain an auditorial state such as if he were listening directly to loud-speakers Witll the auditory image located outside of his head in spite in his actual state clad witll a headphone and continue to listen with the headphone for a long time without feeling fati-gue.
According to the present invention there is provided a headphone system for reproduction of 2-channel stereophonic signals with a pair of headphones, which system comprises a 2- ~-channel stereophonic signal source, two low-pass filters each E
positioned at a cross-talk channel cross-coupling between a respective channel of said 2-channel stereophonic signal source E
and a respective one of said headphones and each provided with t `O a cut-off frequency not greater than 400 Hz and an attentuation characteristic of -1.5 to -6 dB/oct and two adders each provided t for receiving a cross-talk channel signal from the output of one ~;
of said low pass filters and a direct channel signal from said E
stereophonic signal source, the outputs of said adders being respectively coupled to said headphones.
In one embodiment of the present invention the system includes two delay circuits each connected between said stereo-phonic signal source and said low-pass filter and each provided i-for providing a delay time corresponding to the difference be- t~
tween the arrival times of the cross-talk channel and direct F:
channel signal at said headphone.
In another embodiment of the present invention the B
.
- - . : . . . - .
. , . - .~:
.
10~1350 system includes two notch filters each connected between said adder and said headphone for correcting sound pressure versus frequency characteristic occurred due to the use of said head-phone into the substantially same characteristic as that ob-tained by actually listening to sound waves radiated from two loudspeakers of said stereophonic signal source. L
The present invention will be illustrated by way of the accompanying drawings in which:
Fig. 1 is a view schematically illustrating an auditorial 10state of a person listening directly to loudspeakers;
Fig. 2 is a view schematically illustrating an auditorial state of a person listening with a headphone;
Fig. 3 is a view schematically illustrating an auditory path in case of a direct auditorial state;
Figs. 4A to 4F are graphs showing sound pressure versus frequency characteristics with respect to left and right ears of the audiophile in case of Fig. 3 when the angle ~ is set to 15, 30, 45, 60, 75 and 90 respectively; [
Figs. 5A to 5F are graphs showing the (SL - SR) charac-teristics regarding the characteristics in Figs. 4A to 4F; t Fig. 6 is a view schematically illustrating one i ~ :
' ::
i' !
- la -B
. , ;. . ~ .
ofthe stereophonic channels in case of the direct auditorial state;
Fig. 7 is a block diagram showing an embodiment of -the headphone system according to the invention; and ~;
Fig. 8 is a graph showing a fre~uency characteristic -of a notch filter used in the system according to the invention.
Fig. 1 is a view showing an auditorial state of a person listening directly to loudspeakers and where a 2-channelstereophonic signal recorded on a program source such as a record disc or magnetic tape is being reproduced.
In Fig. 1, designated at 1 is a reproducing system re-producing the program source, at 2 and 3 loudspeakers converting the respective left and right signals reproduced from the reproducing system 1 into sound,at4 an audiophile, and at 5 and 6 the ears of an audiophile 4. In this case, the sound wave radiated from the loudspeakers 2 and 3 are directly received by the ears 5 and 6 of the ~udiophile 4, and he recognizes the auditory image at a point outside his head, for instance at point A.
Fig. 2 shows an auditorial state in which the reproduc-tion of the same program source as in the case of Fig. 1 enters the ears of the audiophile via a headphone 7. In this case of using the headphone 7, the audiophile 4 recognizes the auditorial image at a point within his head, for instance at point B. Designated at 8 and 9 in the Figure are right and left sound converters of the headphone 7.
The invention features a headphone system, .: ,, - - ::
which permits a person to recog~ize an auditory image at a point outside his head like the case of the direct auditorial state as shown in Fig. 1 while he actually uses the headphone 7 for listening as shown in Fig. 2.
Fig. 3 schematically shows a direct auditorial state where sound wave issuin~ from one of the loudspeakers, namely loudspeaker 3, is directly received hy the right and left ears 5 and 6 of the audiophile 4. In this situation, the sound wave of sound pressure S emerging from the loudspeaker 3 and entering the right and left ears 5 and 6 is guided through the respective auricles to reach the eardrums and give sound pressures SR and SL
to the eardrums of the respective right and left ears 5 and 6.
Figs 4A to 4F show sound pressure versus fre~uency characteristics with respect to the left and right ears when the angle ~ of the loudspeaker 3 in Fig. 3 with respect to the line directed right forward from the front of the audiophile 4 is set to 15, 30, 45, 60, 75 ;
and 90, respectively.
Figs. 5A to 5F show the difference between the sound pressure SL of the left ear 6 and the sound pressure SR of the right ear 5 in the respective cases of Figs. 4A
to 4F. It will be seen that for ~ = 15 , 30, 45, 60, 75 or 90 , the value of (SR - SL) begins to decrease with frequency from the neighborhood of 400 Hz. In Figs. 5A
to 5F, the plots A15 to Ago represent the approximation of the value (SL - SR). The cut-off frequencies and attenuation characteristics of Al5 to Ago are as follows.
- , :, :
lOS1350 Cut-off frequency Attenuation characteristic A15 250 (Hz) -l.S (dB/oct) A30 220 ~3 A45 200 -3.5 Ago 400 ~4-5 The time lag T between the instants of arrival of the sound wave issued from the loudspeaker 3 at the ears 5 and 6 is determined by the angle 0, the distance d between the ears of the audiophile 4 and the speed C of sound and is given as -T = d sin ~
If ~ = 30, d = 17 cm and C = 340 m/s, the time lag T 8 250 ~ sec.
In the case of the auditorial state shown in Fig. 6, where the audiophile 4 uses the headphone 7, one of the 2-channel signals, for instance, the left channel signal, is converted by the left-hand sound converter 9 of the headphone 7 and is transmitted to the left ear only. Also, since the sound converter 9 directly bears on the ear 6, a peculiar sound pressure versus frequency characteristic is provided due to the presence of the auricule between the sound converter 9 and the eardrum of the left ear. More particularly, when the headphone bears on the ear a peculiar sound pressure versus frequency characteristic (SH) shown by the dashed curve in Fig. 4B, with a resonant frequency fl, is provided due to the presence of the auricule.
10~i13S0 It will be seen from a comparison of Figs. 3 and 6 that in the auditorial state with a headphone a peculiar sound pressure versus frequency characteristic which is absent in the case of the direct auditorial state prevails due to the presence of the headphone and also that in the state with a headphone the right channel signal is transmitted only to the left ear; that is, in the auditorial state with a headphone the intelligence that would reach from the right-hand speaker 3, for instance, to the right ear 5 in the case of the direct auditorial state is lacking. Due to this difference the auditory image is located within the audiophile's head when he listens with the headphone. The invention is predicated on the above considerations and permits realization of practically the same auditorial state as the direct one while wearing the headphone by making the peculiar charac-teristic to the auditorial state with the headphone coincide with that in the direct auditorial state and mixing each ~
channel signal after passing it through a delay circuit and ~-a filter with the other channel signal. ~
An embodiment of the invention will now be described -with reference to Fig. 7. In the Figure, designated at 10 and 11 are delay circuits each providing the afore-mentioned delay time T, at 12 and 13 low pass filters with a cut-off frequency not greater than 400 Hz and an attenuating charac-teristic of -1.5 to -6 dB/oct as shown in Figs. 5A to 5F, at 14 and 15 adders, and at 16 and 17 notch filters attenua-ting only a particular frequency fl as shown in Fig. 8. The notch filters 16 and 17 are provided to correct the character-istic due to the use of -' . ~ ' ' ,: ,. ' .
1 the headphone as shown by the dashed curve in Fig. 4~
for obtaining the same sound pressure versus frequency characteristic (S~) as in the case of the direct auditorial state.
As has been shown in the foregoing, in the head-phone system according to the invention notch filters are used to couple the signals to the headphone so that the characteristic peculiar to the auditorial state using the headphone is removed. Also, since each of the 2-10 channel signals is mixed with the other channel signal :-after passing through the delay circuit and filter, it is possible to obtain the same auditorial state as the direct one while actually using the headphone for listen-;~ -.
A ing~ ~ is, in spite of the auditorial state of a person wearing the headphone, he can recognize the auditory image located outside his head without feeling any oppres-sive sensation peculiar to the auditorial state using the headphone and continue this state for a long time without feeling fatigue.
~ ,.. ,.,." ' '
phone.
The invention provides a headphone system which enables an audiophile, when he merely connects a simple electric circuit between a reproducing system and a usual headphone, to obtain an auditorial state such as if he were listening directly to loud-speakers Witll the auditory image located outside of his head in spite in his actual state clad witll a headphone and continue to listen with the headphone for a long time without feeling fati-gue.
According to the present invention there is provided a headphone system for reproduction of 2-channel stereophonic signals with a pair of headphones, which system comprises a 2- ~-channel stereophonic signal source, two low-pass filters each E
positioned at a cross-talk channel cross-coupling between a respective channel of said 2-channel stereophonic signal source E
and a respective one of said headphones and each provided with t `O a cut-off frequency not greater than 400 Hz and an attentuation characteristic of -1.5 to -6 dB/oct and two adders each provided t for receiving a cross-talk channel signal from the output of one ~;
of said low pass filters and a direct channel signal from said E
stereophonic signal source, the outputs of said adders being respectively coupled to said headphones.
In one embodiment of the present invention the system includes two delay circuits each connected between said stereo-phonic signal source and said low-pass filter and each provided i-for providing a delay time corresponding to the difference be- t~
tween the arrival times of the cross-talk channel and direct F:
channel signal at said headphone.
In another embodiment of the present invention the B
.
- - . : . . . - .
. , . - .~:
.
10~1350 system includes two notch filters each connected between said adder and said headphone for correcting sound pressure versus frequency characteristic occurred due to the use of said head-phone into the substantially same characteristic as that ob-tained by actually listening to sound waves radiated from two loudspeakers of said stereophonic signal source. L
The present invention will be illustrated by way of the accompanying drawings in which:
Fig. 1 is a view schematically illustrating an auditorial 10state of a person listening directly to loudspeakers;
Fig. 2 is a view schematically illustrating an auditorial state of a person listening with a headphone;
Fig. 3 is a view schematically illustrating an auditory path in case of a direct auditorial state;
Figs. 4A to 4F are graphs showing sound pressure versus frequency characteristics with respect to left and right ears of the audiophile in case of Fig. 3 when the angle ~ is set to 15, 30, 45, 60, 75 and 90 respectively; [
Figs. 5A to 5F are graphs showing the (SL - SR) charac-teristics regarding the characteristics in Figs. 4A to 4F; t Fig. 6 is a view schematically illustrating one i ~ :
' ::
i' !
- la -B
. , ;. . ~ .
ofthe stereophonic channels in case of the direct auditorial state;
Fig. 7 is a block diagram showing an embodiment of -the headphone system according to the invention; and ~;
Fig. 8 is a graph showing a fre~uency characteristic -of a notch filter used in the system according to the invention.
Fig. 1 is a view showing an auditorial state of a person listening directly to loudspeakers and where a 2-channelstereophonic signal recorded on a program source such as a record disc or magnetic tape is being reproduced.
In Fig. 1, designated at 1 is a reproducing system re-producing the program source, at 2 and 3 loudspeakers converting the respective left and right signals reproduced from the reproducing system 1 into sound,at4 an audiophile, and at 5 and 6 the ears of an audiophile 4. In this case, the sound wave radiated from the loudspeakers 2 and 3 are directly received by the ears 5 and 6 of the ~udiophile 4, and he recognizes the auditory image at a point outside his head, for instance at point A.
Fig. 2 shows an auditorial state in which the reproduc-tion of the same program source as in the case of Fig. 1 enters the ears of the audiophile via a headphone 7. In this case of using the headphone 7, the audiophile 4 recognizes the auditorial image at a point within his head, for instance at point B. Designated at 8 and 9 in the Figure are right and left sound converters of the headphone 7.
The invention features a headphone system, .: ,, - - ::
which permits a person to recog~ize an auditory image at a point outside his head like the case of the direct auditorial state as shown in Fig. 1 while he actually uses the headphone 7 for listening as shown in Fig. 2.
Fig. 3 schematically shows a direct auditorial state where sound wave issuin~ from one of the loudspeakers, namely loudspeaker 3, is directly received hy the right and left ears 5 and 6 of the audiophile 4. In this situation, the sound wave of sound pressure S emerging from the loudspeaker 3 and entering the right and left ears 5 and 6 is guided through the respective auricles to reach the eardrums and give sound pressures SR and SL
to the eardrums of the respective right and left ears 5 and 6.
Figs 4A to 4F show sound pressure versus fre~uency characteristics with respect to the left and right ears when the angle ~ of the loudspeaker 3 in Fig. 3 with respect to the line directed right forward from the front of the audiophile 4 is set to 15, 30, 45, 60, 75 ;
and 90, respectively.
Figs. 5A to 5F show the difference between the sound pressure SL of the left ear 6 and the sound pressure SR of the right ear 5 in the respective cases of Figs. 4A
to 4F. It will be seen that for ~ = 15 , 30, 45, 60, 75 or 90 , the value of (SR - SL) begins to decrease with frequency from the neighborhood of 400 Hz. In Figs. 5A
to 5F, the plots A15 to Ago represent the approximation of the value (SL - SR). The cut-off frequencies and attenuation characteristics of Al5 to Ago are as follows.
- , :, :
lOS1350 Cut-off frequency Attenuation characteristic A15 250 (Hz) -l.S (dB/oct) A30 220 ~3 A45 200 -3.5 Ago 400 ~4-5 The time lag T between the instants of arrival of the sound wave issued from the loudspeaker 3 at the ears 5 and 6 is determined by the angle 0, the distance d between the ears of the audiophile 4 and the speed C of sound and is given as -T = d sin ~
If ~ = 30, d = 17 cm and C = 340 m/s, the time lag T 8 250 ~ sec.
In the case of the auditorial state shown in Fig. 6, where the audiophile 4 uses the headphone 7, one of the 2-channel signals, for instance, the left channel signal, is converted by the left-hand sound converter 9 of the headphone 7 and is transmitted to the left ear only. Also, since the sound converter 9 directly bears on the ear 6, a peculiar sound pressure versus frequency characteristic is provided due to the presence of the auricule between the sound converter 9 and the eardrum of the left ear. More particularly, when the headphone bears on the ear a peculiar sound pressure versus frequency characteristic (SH) shown by the dashed curve in Fig. 4B, with a resonant frequency fl, is provided due to the presence of the auricule.
10~i13S0 It will be seen from a comparison of Figs. 3 and 6 that in the auditorial state with a headphone a peculiar sound pressure versus frequency characteristic which is absent in the case of the direct auditorial state prevails due to the presence of the headphone and also that in the state with a headphone the right channel signal is transmitted only to the left ear; that is, in the auditorial state with a headphone the intelligence that would reach from the right-hand speaker 3, for instance, to the right ear 5 in the case of the direct auditorial state is lacking. Due to this difference the auditory image is located within the audiophile's head when he listens with the headphone. The invention is predicated on the above considerations and permits realization of practically the same auditorial state as the direct one while wearing the headphone by making the peculiar charac-teristic to the auditorial state with the headphone coincide with that in the direct auditorial state and mixing each ~
channel signal after passing it through a delay circuit and ~-a filter with the other channel signal. ~
An embodiment of the invention will now be described -with reference to Fig. 7. In the Figure, designated at 10 and 11 are delay circuits each providing the afore-mentioned delay time T, at 12 and 13 low pass filters with a cut-off frequency not greater than 400 Hz and an attenuating charac-teristic of -1.5 to -6 dB/oct as shown in Figs. 5A to 5F, at 14 and 15 adders, and at 16 and 17 notch filters attenua-ting only a particular frequency fl as shown in Fig. 8. The notch filters 16 and 17 are provided to correct the character-istic due to the use of -' . ~ ' ' ,: ,. ' .
1 the headphone as shown by the dashed curve in Fig. 4~
for obtaining the same sound pressure versus frequency characteristic (S~) as in the case of the direct auditorial state.
As has been shown in the foregoing, in the head-phone system according to the invention notch filters are used to couple the signals to the headphone so that the characteristic peculiar to the auditorial state using the headphone is removed. Also, since each of the 2-10 channel signals is mixed with the other channel signal :-after passing through the delay circuit and filter, it is possible to obtain the same auditorial state as the direct one while actually using the headphone for listen-;~ -.
A ing~ ~ is, in spite of the auditorial state of a person wearing the headphone, he can recognize the auditory image located outside his head without feeling any oppres-sive sensation peculiar to the auditorial state using the headphone and continue this state for a long time without feeling fatigue.
~ ,.. ,.,." ' '
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. The headphone system for reproduction of 2-channel stereophonic signals with a pair of headphones, which system comprises a 2-channel stereophonic signal source, two low-pass filters each positioned at a cross-talk channel cross-coupling between a respective channel of said 2-channel stereophonic signal source and a respective one of said headphones and each provided with a cut-off frequency not greater than 400 Hz and an attentuation characteristic of -1.5 to -6 dB/oct and two adders each provided for receiving a cross-talk channel signal from the output of one of said low pass filters and a direct channel signal from said stereophonic signal source, the out-puts of said adders being respectively coupled to said head-phones.
2. A headphone system according to Claim 1, which in-cludes two delay circuits each connected between said stereo-phonic signal source and a respective one of said low-pass fil-ters and each provided for providing a delay time corresponding to the difference between the arrival times of the cross-talk channel signal and the direct channel signal at the respective headphone.
3. A headphone system according to Claim 2, which in-cludes two notch filters each connected between respective said adders and respective said headphones for correcting sound pressure versus frequency characteristic occurring due to the use of said headphones into the substantially same characteris-tic as that obtained by actually listening to sound waves radia-ted from two loudspeakers of said stereophonic signal source.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP50002919A JPS5175429A (en) | 1974-12-25 | 1974-12-25 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1051350A true CA1051350A (en) | 1979-03-27 |
Family
ID=11542750
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA242,592A Expired CA1051350A (en) | 1974-12-25 | 1975-12-24 | Headphone system |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5175429A (en) |
| CA (1) | CA1051350A (en) |
| DE (1) | DE2557516C3 (en) |
| FR (1) | FR2296340A1 (en) |
| GB (1) | GB1517938A (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4136260A (en) * | 1976-05-20 | 1979-01-23 | Trio Kabushiki Kaisha | Out-of-head localized sound reproduction system for headphone |
| DE2918831C2 (en) * | 1979-05-10 | 1982-09-30 | Institut für Rundfunktechnik GmbH, 8000 München | Circuit arrangement for adapting a room-related stereophonic program signal to free-field equalized headphones |
| DE2918776C2 (en) * | 1979-05-10 | 1984-07-19 | Kronester, Walter, Dipl.-Ing., 8000 München | Circuit arrangement for adapting a room-related stereophonic program signal to free-field equalized headphones |
| AT394650B (en) * | 1988-10-24 | 1992-05-25 | Akg Akustische Kino Geraete | ELECTROACOUSTIC ARRANGEMENT FOR PLAYING STEREOPHONER BINAURAL AUDIO SIGNALS VIA HEADPHONES |
| DE69632889T2 (en) * | 1995-05-22 | 2005-07-21 | Victor Company of Japan, Ltd., Yokohama | Player with headphones |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2244162C3 (en) * | 1972-09-08 | 1981-02-26 | Eugen Beyer Elektrotechnische Fabrik, 7100 Heilbronn | "system |
-
1974
- 1974-12-25 JP JP50002919A patent/JPS5175429A/ja active Pending
-
1975
- 1975-12-12 GB GB5105075A patent/GB1517938A/en not_active Expired
- 1975-12-19 DE DE19752557516 patent/DE2557516C3/en not_active Expired
- 1975-12-22 FR FR7539283A patent/FR2296340A1/en active Granted
- 1975-12-24 CA CA242,592A patent/CA1051350A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1517938A (en) | 1978-07-19 |
| DE2557516B2 (en) | 1979-02-01 |
| FR2296340A1 (en) | 1976-07-23 |
| DE2557516C3 (en) | 1979-09-20 |
| DE2557516A1 (en) | 1976-07-15 |
| JPS5175429A (en) | 1976-06-30 |
| FR2296340B1 (en) | 1981-09-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1194007B1 (en) | Method and signal processing device for converting stereo signals for headphone listening | |
| JP3657120B2 (en) | Processing method for localizing audio signals for left and right ear audio signals | |
| US4308423A (en) | Stereo image separation and perimeter enhancement | |
| EP1680941B1 (en) | Multi-channel audio surround sound from front located loudspeakers | |
| US5276740A (en) | Earphone device | |
| US4355203A (en) | Stereo image separation and perimeter enhancement | |
| GB1437129A (en) | Method and apparatus for imparting to headphones the sound- reproducing characteristics of loudspeakers | |
| US4359605A (en) | Monaural signal to artificial stereo signals convertings and processing circuit for headphones | |
| KR100727973B1 (en) | Acoustic reproducing apparatus and method for enhancing low-frequency content | |
| US4087631A (en) | Projected sound localization headphone apparatus | |
| CA1051350A (en) | Headphone system | |
| US4449229A (en) | Signal processing circuit | |
| JP2944424B2 (en) | Sound reproduction circuit | |
| CN105357624A (en) | Loudspeaker replaying double-track signal processing method, device and system | |
| KR102155574B1 (en) | Method for noise cancelling of open headphone and apparatus using the same | |
| JP2567585B2 (en) | Stereoscopic information playback device | |
| WO2011068192A1 (en) | Acoustic conversion device | |
| KR100275779B1 (en) | A headphone reproduction apparaturs and method of 5 channel audio data | |
| JPS5918920B2 (en) | Onkyo Shingo Saisei Souchi | |
| JP2004527961A (en) | Method and circuit for listening to sound recording media with a headset | |
| GB2003706A (en) | Audio signal translation for loudspeaker and headphone sound reproduction | |
| JP2003032782A (en) | Sound-reproducing system | |
| JPH0795877B2 (en) | Multi-dimensional sound field reproduction device | |
| JPH02219400A (en) | Stereophonic sound reproducing device | |
| JPH0946798A (en) | Pseudo stereoscopic device |