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EP0160431A2
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Sound field correction system
Assignee: Pioneer Corp
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Filing: 1985-04-09
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Granted: —
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Expires: 2005-04-09
Abstract
Abstract A sound field correcting system for correcting for multipath frequency-characteristic distortion in an acoustic reproducing system. In one embodiment, the level and delay of an original signal are adjusted and superposed on the original signal so as to obtain a signal which, when reproduced by a loudspeaker, yields a sound pattern at a listening point having a flat frequency characteristic. The delay adjustment is effected in accordance with a difference between the travel distances of direct and reflected sound waves to the listening point.
Inventors
- 👤 Yoshio C/O Pioneer Electronic Corporation Sasaki
- 👤 Yoshiro C/O Pioneer Electronic Corporation Kunugi
- 👤 Toshikazu Pioneer Electronic Corporation Yoshimi
- 👤 Shinjiro C/O Pioneer Electronic Corporation Kato
- 👤 Shuichi C/O Pioneer Electronic Corporation Mori
- 👤 Takeshi C/O Pioneer Electronic Corporation Sato
- 👤 Makoto C/O Pioneer Electronic Corporation Odaka
- 👤 Akio C/O Pioneer Electronic Corporation Tokumo
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 03:00
CPC Classifications
H; H04; H04S; H04S1/00; H04S1/002; H03; H03G; H03G5/00; H03G5/02; H03G5/04; H04R; H04R3/00; H04R3/04
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
76 words
A sound field correcting system for correcting a sound field formed by a direct sound wave and reflected sound wave thereof, comprising: means for adjusting a level and delay of an original signal; and means for superposing an output signal of said adjusting means onsaid original signal to obtain a signal which is applied to said loudspeaker, thereby to eliminate an effect of said reflected sound wave at a predetermined listening point in said sound field.
Claim 2
Dependent Claim
76 words
A sound field correcting system for correcting a sound field formed by a direct sound wave and reflected sound wave thereof, comprising: means for adjusting a level and delay of an original signal; and means for superposing an output signal of said adjusting means onsaid original signal to obtain a signal which is applied to said loudspeaker, thereby to eliminate an effect of said reflected sound wave at a predetermined listening point in said sound field.
Claim 3
Dependent Claim
40 words
The system as claimed in claim 1, wherein delay adjustment by said adjusting means is effected in accordance with at least a difference between travel distance of said direct sound wave and reflected sound wave to said predetermined listening point.
Claim 4
Dependent Claim
96 words
A sound field correcting system for correcting a sound field formed by a direct sound wave radiated directly from a loudspeaker and a reflected sound wave thereof, comprising: means for adjusting a level and delay of an original signal; a high-pass filter inserted in a signal transmission path in said adjusting means; and means for superposing an output signal of said adjusting means on said original signal to obtain a signal which is applied to said loudspeaker, thereby to eliminate an effect of said reflected sound wave at a predetermined listening point in said sound field.
Claim 5
Dependent Claim
96 words
A sound field correcting system for correcting a sound field formed by a direct sound wave radiated directly from a loudspeaker and a reflected sound wave thereof, comprising: means for adjusting a level and delay of an original signal; a high-pass filter inserted in a signal transmission path in said adjusting means; and means for superposing an output signal of said adjusting means on said original signal to obtain a signal which is applied to said loudspeaker, thereby to eliminate an effect of said reflected sound wave at a predetermined listening point in said sound field.
Claim 6
Dependent Claim
110 words
A sound field correcting system comprising: means for delaying a sound signal; level adjusting means for adjusting a level of said sound signal thus delayed; phase inverting means for inverting a phase of said signal thus level-adjusted; and mixing means for mixing said signal thus phase-inverted and said sound frequency characteristic at a listening point caused by interference of a direct sound wave radiated directly from a loudspeaker and a reflected sound wave thereof, wherein the improvement comprises a low-pass filter connected between said delay means and said level adjusting means, a frequency characteristic of said low-pass filter being determined according to a frequency characteristic of said reflected sound wave.
Claim 7
Dependent Claim
110 words
A sound field correcting system comprising: means for delaying a sound signal; level adjusting means for adjusting a level of said sound signal thus delayed; phase inverting means for inverting a phase of said signal thus level-adjusted; and mixing means for mixing said signal thus phase-inverted and said sound frequency characteristic at a listening point caused by interference of a direct sound wave radiated directly from a loudspeaker and a reflected sound wave thereof, wherein the improvement comprises a low-pass filter connected between said delay means and said level adjusting means, a frequency characteristic of said low-pass filter being determined according to a frequency characteristic of said reflected sound wave.
Claim 8
Dependent Claim
16 words
The system as claimed in claim 4, wherein said low-pass filter has a variable frequency characteristic.
Claim 9
Dependent Claim
140 words
A sound field correcting system for correcting a sound field formed by a direct sound wave radiated directly from a loudspeaker and a reflected sound wave thereof, comprising: adjusting means for adjusting a level and phase of an original signal; and means for superposing outputs of said adjusting means on said original signal to provide a signal which is applied to said loudspeaker, said adjusting means comprising means for producing n signals having levels attenuated by an, where a is a constant defined by 0 < a < 1 and n is a natural number, with respect to a level of said original signal, having polarities defined by (-1) n , and delay times of n· τ, where τ is a constant, thereby eliminating an effect of said reflected sound wave at a predetermined listening point in said sound field.
Claim 10
Dependent Claim
140 words
A sound field correcting system for correcting a sound field formed by a direct sound wave radiated directly from a loudspeaker and a reflected sound wave thereof, comprising: adjusting means for adjusting a level and phase of an original signal; and means for superposing outputs of said adjusting means on said original signal to provide a signal which is applied to said loudspeaker, said adjusting means comprising means for producing n signals having levels attenuated by an, where a is a constant defined by 0 < a < 1 and n is a natural number, with respect to a level of said original signal, having polarities defined by (-1) n , and delay times of n· τ, where τ is a constant, thereby eliminating an effect of said reflected sound wave at a predetermined listening point in said sound field.
Claim 11
Dependent Claim
35 words
The system as claimed in claim 6, wherein said values a and τ are functions of lengths of paths along which said direct sound wave and said reflected sound wave travel to said listening point.
Claim 12
Dependent Claim
105 words
A sound field correcting system for correcting a sound field formed by a direct sound wave radiated directly from a loudspeaker and a reflected sound wave thereof, comprising: adjusting means for adjusting a phase and level of an original signal; and means for superposing output signals of said adjusting means on said original signal to provide a signal which is supplied to said loudspeaker, said adjusting means comprising means for providing correcting signals different in level and phase from said original signal to cancel out a plurality of reflected sound waves which arrive at a predetermined listening point in said sound field through different paths.
Claim 13
Dependent Claim
105 words
A sound field correcting system for correcting a sound field formed by a direct sound wave radiated directly from a loudspeaker and a reflected sound wave thereof, comprising: adjusting means for adjusting a phase and level of an original signal; and means for superposing output signals of said adjusting means on said original signal to provide a signal which is supplied to said loudspeaker, said adjusting means comprising means for providing correcting signals different in level and phase from said original signal to cancel out a plurality of reflected sound waves which arrive at a predetermined listening point in said sound field through different paths.
Claim 14
Dependent Claim
97 words
A sound field correcting system mounted on a vehicle which corrects the acoustic characteristic in the sound field formed inside said vehicle by direct sound waves radiated from front and rear loudspeakers provided respectively for front and rear seats and reflected sound waves thereof, comprising: one pair of correcting means provided for respective drive systems driving said front and rear loudspeakers, each correcting means comprising means for delaying, attenuating and phase inverting an original signal, and means for adding the signal so obtained to said original signal, thereby to make a sound pressure frequency characteristic thereof smooth.
Claim 15
Dependent Claim
97 words
A sound field correcting system mounted on a vehicle which corrects the acoustic characteristic in the sound field formed inside said vehicle by direct sound waves radiated from front and rear loudspeakers provided respectively for front and rear seats and reflected sound waves thereof, comprising: one pair of correcting means provided for respective drive systems driving said front and rear loudspeakers, each correcting means comprising means for delaying, attenuating and phase inverting an original signal, and means for adding the signal so obtained to said original signal, thereby to make a sound pressure frequency characteristic thereof smooth.
Claim 16
Dependent Claim
39 words
The sound field correcting system as claimed in claim 9, further comprising delay means for delaying sound waves radiated from said rear loudspeakers by a predetermined period of time with respect to sound waves radiated from said front loudspeakers.
Claim 17
Dependent Claim
112 words
A sound field correcting system for correcting a sound field formed by direct sound waves radiated from right and left channel loudspeakers for stereo reproduction and reflected sound waves thereof, comprising: first addition means for adjusting a level and delay of a left channel signal to obtain a first signal and adding said first signal thus obtained to said right channel signal; and second addition means for adjusting a level and delay of said right channel signal to obtain a second signal and adding said second signal thus obtained to said left channel signal, outputs of said first and second addition means being applied to said right and left channel loudspeakers, respectively.
Claim 18
Dependent Claim
112 words
A sound field correcting system for correcting a sound field formed by direct sound waves radiated from right and left channel loudspeakers for stereo reproduction and reflected sound waves thereof, comprising: first addition means for adjusting a level and delay of a left channel signal to obtain a first signal and adding said first signal thus obtained to said right channel signal; and second addition means for adjusting a level and delay of said right channel signal to obtain a second signal and adding said second signal thus obtained to said left channel signal, outputs of said first and second addition means being applied to said right and left channel loudspeakers, respectively.
Claim 19
Dependent Claim
120 words
The sound field correcting system for correcting a sound field which is formed by direct sound waves radiated from right and left channel loudspeakers for stereo reproducing and reflected sound waves thereof, comprising: first addition means for adjusting levels and phases of right and left channel signals to obtain first and second signals; means for adding said first and second signals thus obtained to said left channel signal; second addition means for adjusting levels and phase of right and left channel signals to obtain third and fourth signals; and means for adding said third and fourth signals thus obtained to said right channel signal, outputs of said first and second addition means being.applied to said left and right channel loudspeakers.
Claim 20
Dependent Claim
120 words
The sound field correcting system for correcting a sound field which is formed by direct sound waves radiated from right and left channel loudspeakers for stereo reproducing and reflected sound waves thereof, comprising: first addition means for adjusting levels and phases of right and left channel signals to obtain first and second signals; means for adding said first and second signals thus obtained to said left channel signal; second addition means for adjusting levels and phase of right and left channel signals to obtain third and fourth signals; and means for adding said third and fourth signals thus obtained to said right channel signal, outputs of said first and second addition means being.applied to said left and right channel loudspeakers.
Claim 21
Dependent Claim
80 words
A sound field correcting system for correcting a sound field formed by a direct sound wave radiated from a loudspeaker and a reflected sound wave thereof, wherein the improvement comprises: a feedback loop provided in an amplification path between a signal source and a loudspeaker, transfer functions as to the level with frequency and the delay of said feedback loop being determined so as to eliminate effects of said reflected sound wave at a listening point in said sound field.
Claim 22
Dependent Claim
80 words
A sound field correcting system for correcting a sound field formed by a direct sound wave radiated from a loudspeaker and a reflected sound wave thereof, wherein the improvement comprises: a feedback loop provided in an amplification path between a signal source and a loudspeaker, transfer functions as to the level with frequency and the delay of said feedback loop being determined so as to eliminate effects of said reflected sound wave at a listening point in said sound field.
Claim 23
Dependent Claim
51 words
The sound field correcting system as claimed in claim 13, wherein said feedback loop comprises a delay adjusting unit and a level adjusting unit, and wherein a delay time and amount of attenuation of said adjusting units are functions of travel distances of said direct sound wave and reflected sound wave.
Claim 24
Dependent Claim
164 words
A sound field correcting system for correcting a sound field formed by direct sound waves radiated from right and left channel loudspeakers for stereo reproduction, and reflected sound waves thereof, comprising: subtraction means provided respectively in input stages of amplification means provided respectively between a right channel signal source and a right channel loudspeaker and between a left channel signal source and a left channel loudspeaker in a right channel system and a left channel system, respectively; and transmission means for applying a part of a signal applied to said right channel loudspeaker to said subtraction means in the left channel system, and transmission means for applying a part of a signal which is applied to said left channel loudspeaker to said subtraction means in the right channel system, transfer functions as to level with frequency and phase with frequency of each transmission means being determined so as to eliminate effects of said reflected sound waves at a listening point in said sound field.
Claim 25
Dependent Claim
164 words
A sound field correcting system for correcting a sound field formed by direct sound waves radiated from right and left channel loudspeakers for stereo reproduction, and reflected sound waves thereof, comprising: subtraction means provided respectively in input stages of amplification means provided respectively between a right channel signal source and a right channel loudspeaker and between a left channel signal source and a left channel loudspeaker in a right channel system and a left channel system, respectively; and transmission means for applying a part of a signal applied to said right channel loudspeaker to said subtraction means in the left channel system, and transmission means for applying a part of a signal which is applied to said left channel loudspeaker to said subtraction means in the right channel system, transfer functions as to level with frequency and phase with frequency of each transmission means being determined so as to eliminate effects of said reflected sound waves at a listening point in said sound field.
Claim 26
Dependent Claim
52 words
The sound field correcting system as claimed in claim 15, wherein each of said transmission means comprises a delay adjusting unit and a level adjusting unit, a delay time and an amount of attenuation of said adjusting units being functions of travel distances of said direct sound waves and reflected sound waves.
References Cited (Backward Citations)
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