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JP2001069591

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DESCRIPTION JP2001069591
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
directional loudspeaker system capable of listening to sounds of different signal sources in
different areas with respect to a pair of speakers, more specifically, in a predetermined listening
area. And a directional loud-speaker capable of transmitting different sound information to a
plurality of listening areas so as to make it difficult to hear the sound of the signal source and to
hear different sounds in different listening areas.
[0002]
2. Description of the Related Art Conventionally, as a device for enabling different sounds to be
heard simultaneously in different areas of the same space, the directivity of sound radiated from
a speaker is controlled in two or more desired directions. There was something like that. For
example, as shown in FIG. 1 (1), each input signal (AS) supplied to an array speaker (AS) in which
a plurality of speakers are linearly arranged is disclosed in Japanese Unexamined Patent
Publication No. 6-205496 (“Speaker device”). The digital signals (IN1, IN2) are individually
processed by digital filters (DF1 to m) so as to make the delay time and the like different, and
thereby directivity (D1) of each input signal sound emitted from the array speaker (AS) , D2) have
been described, but this technique has the disadvantage of a large scale of the device.
[0003]
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Also, in general, when acoustic signal power is applied in phase with an array speaker physically
arranged in an array, sound pressure other than the front becomes very low due to sound wave
interference, and the directivity becomes very sharp. However, in order to obtain sufficiently
sharp directivity, several wavelengths of sound waves are required for the dimensions in the
longitudinal direction (arrangement direction) of the array speaker. This makes it difficult to fit
within practical dimensions in the low to mid range. For example, since one wavelength of a
sound wave having a frequency of 1 kHz is 34 cm, in order to obtain sufficient directivity at
frequencies lower than this, a large size of 1 m to several m is required.
[0004]
In JP-A-5-344579 ("Speaker system and television receiver using the speaker system"), as shown
in FIG. 1 (2), the speakers of two speaker units (SU) are used. Described is a technology that
provides an acoustic partition (PP) and a sound absorbing panel (AP) to an acoustic tube (ST) that
guides the sound wave emitted from the diaphragm, to give the speaker directivity in any
direction structurally However, this technique has the disadvantage that the suppression ratio
effect is small and the switching of the pointing direction is not easy.
[0005]
On the other hand, the inventors of the present invention have two (or two) people in different
areas of the same space by canceling predetermined sound wave components radiated from two
closely arranged speakers by digital signal processing. Japanese Patent Application No. 1039378 proposes a speaker device in which listeners of one group can listen to the sound of
different sound sources at the same time (this proposal is hereinafter referred to as "the
proposal").
However, in this speaker device, there is a disadvantage that the control frequency band is
narrow, and in particular, the controllable range of the high range becomes narrow.
[0006]
SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention
is directed to a method, in particular, in a certain area in a space where the sound emitted from a
pair of left and right speaker systems is heard. In addition to making it difficult to listen or to be
able to simultaneously listen to the sound of different sound sources in different areas, it is also
possible to expand such hard-to-listen areas and individually listenable areas regardless of the
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frequency band. SUMMARY OF THE INVENTION It is an object of the present invention to
provide an improved directional loudspeaker system which can further improve the controllable
range of the high-pitched range and can simplify the structure and reduce the size.
[0007]
SUMMARY OF THE INVENTION According to the present invention, two mid-bass speakers (5a,
5b) juxtaposed at an interval of 1⁄8 wavelength to 1 wavelength of a sound wave in a control
frequency band; Mid-bass cancellation control means, interposed between the acoustic signal
source (A, B) and the mid-bass speaker, for canceling out the sound waves radiated from the midbass speaker in the listening space by the interference between the sound waves (SC), a
directional loud-speaker comprising directional high-tone speakers (9a, 9b) for emitting sound
based on a high-range acoustic signal from the acoustic signal source, or 8 of sound waves in a
control frequency band Two mid-low range speakers (5a, 5b) juxtaposed at a distance of 1/1
wavelength, and between two acoustic signal sources (A, B) and mid-low range speakers In the
different regions of space, Mid-bass cancellation control means (SC) for canceling out the sound
wave emitted from the speaker by the interference of the sound waves, and for two directivity
high-pitched sounds for emitting the sound based on the high range acoustic signal from the
acoustic signal source A directional loudspeaker system is provided which comprises speakers
(9a, 9b).
[0008]
According to another feature of the present invention, the directional high-pitched speaker can
be configured as an array speaker (SA, SB), and according to another different feature, the midlow range speaker and the directional high-pitched loudspeaker The speaker for an array can be
shared by the array speakers (SA, SB).
Furthermore, in the latter case, the mid-low range speaker is divided into the mid-range speaker
unit (SM) and the low-range speaker unit (SL), and the mid-range speaker unit (SM) is the center
of the array speakers (SA, SB) It can be located on the side, and the bass speaker (SL) can be
located outside of it.
[0009]
According to the first aspect of the present invention, two loudspeakers (5a, 5b) are closely
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arranged via an interval of 1⁄8 wavelength to 1 wavelength of the sound wave of the controlled
frequency domain, The sound wave of the mid-low range acoustic signal in this frequency range
is emitted.
A mid-bass cancellation control means (SC) is interposed between the acoustic signal source (for
example, A) and one of the speakers (5b), whereby in a certain area of the listening space of both
speakers Mid-low range sound waves emitted from the speaker are canceled out by the
interference between the sound waves. With regard to the high-range acoustic signal of the
acoustic signal source, the corresponding high-range acoustic wave is emitted from the
directional high-tone speaker (for example, 9a) in a direction avoiding the cancellation region.
Therefore, it is possible to make it difficult to hear both the middle low tone and the high tone in
the above-mentioned cancellation area and the listening area in the vicinity thereof by using a
speaker device of small size.
[0010]
According to the second aspect of the present invention, two speakers (5a, 5b) are closely
arranged via an interval of 1/8 wavelength of sound wave of controlled frequency domain to 1
wavelength, and the control frequency domain In each of the speakers, sound waves in the midlow range including the first and second channel acoustic signal components having different
content types (that is, no correlation) are emitted from the two speakers. A mid-bass cancellation
control means (SC) is interposed between the second and first channel acoustic signal sources (B,
A) and the first and second speakers, whereby the listening spaces of both speakers are received.
In the first and second different regions, the second or first channel acoustic signal component of
the mid-low range sound wave emitted from each speaker is canceled out by the interference
between the sound waves. With regard to the high frequency range acoustic signals of the first
channel or second channel acoustic signal source (A, B), the corresponding high frequency range
sound signals are transmitted from the midrange low frequency sound waves from the
directional high frequency speakers (9a, 9b), respectively. Sound is emitted in a direction toward
the region where the second channel or first channel acoustic signal component is canceled.
Thus, using small sized loudspeaker devices, separate sounds from the first or second channel
acoustic signal source (A, B) at each cancellation area and each listening area in its vicinity, midlow range Both the sound of the treble and the sound of the treble can be heard effectively.
[0011]
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According to the present invention, in this way, for the mid-low range, the mid-bass cancellation
control means (SC) is used to mutually generate the sound from the two speakers (5a, 5b) using
the sound wave interference. With regard to the high-pitched range, by raising the sound
pressure level only in a specific direction toward the listening area using the directivity highpitched speakers (9a, 9b), the separate high-pitched sound information is divided into a plurality
of listening areas Can be effectively transmitted. Further, according to another feature of the
present invention, by using the directivity high-tone speaker (9a, 9b) as a high-directivity sound
source such as an array speaker, separate sounds for each listening area including the high-tone
range are used. Effective transmission of information can be realized with a simple configuration.
[0012]
Further, according to another feature of the present invention, mid-low range speakers are also
included in the array speakers (SA, SB), and part or all of the array speakers are mid-low range
cancellation control means (SC). The speaker structure can be further simplified by using as a
mid-low range speaker driven through the. In this case, the mid-low range speaker is divided into
the mid-range speaker unit (SM) and the low-range speaker unit (SL), and the mid-range speaker
unit (SM) is positioned on the center side of the array speakers (SA, SB) Various effective
methods can be adopted depending on the listening environment, such as positioning the bass
speaker unit (SL) outside thereof.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present
invention will now be described in detail with reference to the drawings. The following
embodiments are merely examples, and various modifications can be made without departing
from the spirit of the present invention.
[0014]
[System Configuration] FIG. 2 is a block diagram showing the configuration of a directional
loudspeaker system according to an embodiment of the present invention. In this example, the
first and second channel acoustic signals A and B having different content types (that is, no
correlation) are input to this directional loudspeaker system, and these two acoustic signals A
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and B are After being converted into digital signals by analog-to-digital converters (ADCs) 1a and
1b, the digital signals are supplied to an acoustic signal control circuit 2.
[0015]
The acoustic signal control circuit 2 includes first and second delay units 21 and 22 and first and
second digital filters 23 and 24, and the first delay unit 21 and the first digital filter 23 have a
first channel. The acoustic signal A is supplied, and the second delay unit 22 and the second
digital filter 24 are supplied with a second channel acoustic signal B. The output signals of the
first delay unit 21 and the second digital filter 24 in the acoustic signal control circuit 2 are
respectively transmitted through the digital analog conversion circuits (DACs) 31 and 34 and the
first and second attenuators AT. The output signals of the second delay unit 22 and the first
digital filter 23 in the acoustic signal control circuit 2 are summed by the summing circuit AD,
and output from the second delay unit 22 through the DACs 32 and 33 and the third and fourth
attenuators AT, respectively. Addition is performed by the addition circuit AD.
[0016]
The addition output signals of the addition circuits AD are respectively amplified by the first and
second power amplifiers 4a and 4b, and then input to the first and second mid-bass speakers 5a
and 5b. Both mid-low range speakers 5a and 5b are disposed at an interval (d0) between the
eighth wave and the first wave of the sound wave of the main control frequency domain of the
first and second channel acoustic signals A and B, respectively. , Emit a sound wave based on the
signals input from the first and second power amplifiers 4a and 4b.
[0017]
The ADCs 1a and 1b, the acoustic signal control circuit 2, the DACs 31 to 34, the attenuator AT,
the adder circuit AD, and the first and second power amplifiers 4a and 4b described above are a
crossover network type of sound source control. A proximity sound source control (PSC:
Proximate Sourse Control) method [in the following, "PSC method" by configuring the device SC
and driving the first and second mid-bass speakers 5a, 5b by the sound source control device SC
It is abbreviated and expressed. Is realized. When the mid-low range speakers 5a and 5b are
driven by this PSC method, two different points Pa and Pb in the listening space (not shown). For
example, in FIG. 2, left front and right front with the first and second middle bass speakers 5a
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and 5b as backs, respectively. ) To listen only to the first channel or second channel acoustic
signal component (A, B), respectively, and to make the crosstalk sound from the second channel
or first channel acoustic signal B, A inaudible Can. Such proximity control sound source has
already been described in the above proposal, but the principle will be described later.
[0018]
In one embodiment of the present invention, as shown in FIG. 2, sound source control is
performed for the mid-bass range of about 100 Hz to 2500 Hz (or 3000 Hz) of the first and
second channel acoustic signals A and B. The first and second mid-bass speakers 5a and 5b are
driven by the device SC in a PSC system, and the first and second channel acoustic signals A and
B have a high frequency range of about 3 kHz (or 2.5 kHz) to 15 kHz. For sound, high-pass filters
6a and 6b, power amplifiers 7a and 7b, distribution circuits 8a and 8b, and high directivity
speakers 9a and 9b are provided to provide desired directivity to the high-range sound. I am
trying to get it. That is, high-pass signals of the first and second channels obtained by passing the
first and second channel acoustic signals A and B through the high-pass filters 6a and 6b,
respectively, are amplified by the power amplifiers 7a and 7b. After predetermined signal
strength gradients are applied by the distribution circuits 8a and 8b, the tone generation units of
the high-tone array speakers 9a and 9b are supplied.
[0019]
Here, as the directivity high-tone speakers 9a and 9b, as shown in FIG. 2, an array speaker having
narrow (high) directivity in a band of 3 kHz (or 2.5 kHz) to 15 kHz is used. It is suitable.
However, speakers having the same directivity (for example, those having the structure as shown
in FIG. 1 (1) having the physically equivalent directivity) may be used. FIG. 3 is a view showing
the appearance of a directional loudspeaker in accordance with an embodiment of the present
invention. It is set so that only the first channel or second channel acoustic signal components (A,
B) can be listened to at the listening points Pa, Pb by driving the mid-low range speakers 5a, 5b
by the PSC method. Assuming that each of the high-tone array speakers 9a and 9b inclines in the
physical arrangement direction as shown in FIGS. 2 to 3, each of the high-tone array speakers 9a
and 9b adjusts the intensity gradient of the signal supplied to the sound generation unit. A
predetermined directivity characteristic is given in the direction toward the listening points Pa
and Pb.
[0020]
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[Principle of PSC System] A certain point Pa (not shown) in the acoustic listening space for the
low-mid range loudspeakers 5a and 5b. For example, in FIG. 2, the first mid-bass speaker 5a is on
the back left side. Considering), the sound to be heard at this point Pa is a linear superposition of
the sound pressure due to the sound emitted from the first and second mid-bass speakers 5a, 5b.
Therefore, the sound pressure S (ω) at the listening point Pa is X (ω) for the voltage of the first
channel acoustic signal A and Y (ω) for the second channel acoustic signal B (where ω is a
sound signal And the following equation (1): S = (α X + β Y) + (γ X + δ Y) (1) where α is the
circuit element 1a → 21 → 31 → 4a → 5a and the space 5a Transfer function between elements
1a to 5a to Pa with path → Pa, β is transfer function between elements 1b to 5a to Pa with path
from circuit element 1b → 24 → 34 → 4a → 5a and space 5a → Pa , Γ is the circuit element 1a
→ 23 → 33 → 4b → 5b and the space 5b → Pa is the path The transfer function δ between 1a
to 5b to Pa is the circuit element 1b → 22 → 32 → 4b → 5b and the space 5b It is a transfer
function between 1b-5b and Pa which makes-> Pa the path | route.
[0021]
That is, the first term on the right side represents the sound radiated from the first mid-bass
speaker 5a and heard at the listening point Pa, and the second term on the right side is radiated
from the second mid-bass speaker 5b. It represents the sound to be heard at the same listening
point Pa. Therefore, when the digital coefficient of the second digital filter 24 is adjusted to
change the coefficient β and β = −δ is established, the equation (1) is obtained from the
equation (1) and the second channel acoustic signal voltage Y is included. You can delete terms. S
= αX + γX = (α + γ) X (2)
[0022]
In this sense, at the listening point Pa, only the sound derived from the first channel acoustic
signal A (signal voltage X) is heard, and the crosstalk noise derived from the second channel
acoustic signal B (signal voltage Y) [(Β + δ) Y] indicates that it can not be heard.
[0023]
The same operation is performed at another point Pb (not shown) symmetrical with respect to
the center line between the mid-low range speakers 5a and 5b at the listening point Pa.
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For example, in FIG. 2, the second mid-bass speaker 5b is on the back and right front. ) By
adjusting α = −γ also to the filter of the first digital filter 23 so that only the sound originating
from the second channel acoustic signal B (signal voltage Y) is heard at the listening point Pb.
Thus, crosstalk sound [(.alpha. +. Gamma.) X] derived from the first channel acoustic signal A
(signal voltage X) can be prevented from being heard.
[0024]
In such a configuration, only one point in the listening space can satisfy β = -δ or α = -γ by
each digital filter 23 and 24, and one point (hereinafter referred to as "cancellation It is called
point. )においてクロストークはゼロとなる。 In addition, around the cancellation point, an area
with less crosstalk is generated.
[0025]
For example, in the case where the crosstalk at the listening point Pa is made zero by adjusting
the filter coefficient of the second digital filter 24 to establish β = −δ, the crosstalk is
generated near the listening point Pa. When crosstalk is reduced to zero at the listening point Pb
by adjusting the filter coefficient of the first digital filter 23, crosstalk is reduced in the vicinity of
the listening point Pb symmetrical thereto. This is clarified by the present inventors, as will be
described below, and the invention utilizing this phenomenon is described in detail in the above
proposal.
[0026]
In general, when the speakers are placed sufficiently apart in the diffuse sound field, the space
where the crosstalk is -10 dB is substantially circular, and one tenth of the wavelength of the
sound wave in the control band. It is said that it will be of a large size (eg, “A. David and S. J.
Elliot 1993 applied acoustics 41, 63-79. See “Numerical studies of actively generated quiete
zones”). Also, conversely, when the sound source speakers are brought close to 1/8 or less of
the wavelength of the sound wave of the control frequency, the area where crosstalk is less than 10 dB spreads in front of both of the two speakers, It has been found that in the case of {circle
over (2)}, the areas of crosstalk reduction overlap each other.
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[0027]
In a system in which mid-low range speakers 5a and 5b are juxtaposed as shown in FIG. 2, when
the wavelength of the sound to be emitted is λ, the crosstalk is -10 dB when the loudspeaker
interval is changed. The reduction region changes as a function of loudspeaker spacing for a
given wavelength λ. When the speakers 5a and 5b are sufficiently separated from each other to
have a relationship of "speaker distance d1> wavelength λ", crosstalk is reduced in a
substantially circular small area [see the above-mentioned proposed FIG. 2 (A). ]. Further, when
the two speakers 5a and 5b are brought close to each other and have a relationship of "speaker
distance d2> (1/8) × wavelength λ", the crosstalk reduction region is greatly expanded, but the
first channel and the second channel Cross talk reduction regions for acoustic signal components
overlap each other [see FIG. 2 (C) of the proposal. ].
[0028]
However, when the speaker spacing d0 is set to (1/8) × λ <d0 <λ (3) as in the present
invention, the crosstalk reduction region of each acoustic signal component is independent. The
weir also has a large volume [see FIG. 2 (B) in the proposal above. ]. In the sound field based on
such PSC method, in FIG. 2, the sound source control device SC makes the first and second midbass speakers 5a, 5b (for example, the distance d0 between the centers of the mid-bass speakers
5a, 5b approximately It can be within 40 cm. Is realized by the proximity control sound source
driving the
[0029]
[Summary of Sound Field Formation in Mid-Low Range and High-Range Range] According to
such PSC method, the sound pressure in a specific direction is selected for the mid-low range
sound of about 100 Hz to 2500 Hz (or 3000 Hz). It is possible to lower the area where crosstalk
is reduced well and make the volume even larger, but for high-pitched sounds of 2500 Hz (or
3000 Hz) or more, the controllable crosstalk reduction area is narrow. It is difficult to achieve the
desired effect.
[0030]
Therefore, in one embodiment of the present invention, as shown in FIG. 2, the PSC system is
used by the sound source control device SC for the mid-low range sound of the first and second
channel acoustic signals A and B. Drive the first and second mid-bass speakers 5a and 5b, and for
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the high-pitched sounds of the first and second channel acoustic signals A and B, respectively,
the high-pass filters 6a and 6b, and the power Amplifiers 7a and 7b, distribution circuits 8a and
8b, and high directivity speakers 9a and 9b having high directivity are provided.
[0031]
FIGS. 4 and 5 are diagrams for explaining the formation of mid-low range sound fields by the PSC
type mid-low range speakers 5a and 5b in the present invention, and FIG. 6 is a directivity highpitched sound in the present invention. It is a figure for demonstrating formation of the high
sound area sound field by the speakers 9a and 9b.
For example, it is assumed that a broadcast sound signal of "English" is input as the first channel
sound signal A and a broadcast sound signal of "Spanish" is input as the second channel sound
signal B in the sound source control device SC.
[0032]
In the present invention, for example, the PSC system is applied to the pair of mid-low range
speakers 5a and 5b in pairs for mid-low range sounds of 100 Hz to 2500 Hz (or 3000 Hz). Make
the direction (DA) where the sound of the channel is hard to hear, and similarly make the
direction (DB) where the sound of the other channel is hard to hear in the other direction.
For example, for "Spanish" of the second channel acoustic signal B, a sound field is generated in
which the direction in which it is difficult to hear is the direction indicated by "DA" in FIG. In the
case of “1”, the proximity control sound source including the sound source control device SC is
set so as to generate a sound field in which the direction that is difficult to hear is the direction
indicated by “DB” in FIG. Then, when the acoustic signals A and B of these two channels are
overlapped and reproduced by this proximity control sound source, as shown in FIG. 5, two
directions DA and DB in which only "English" or "Spanish" can be easily heard As a result,
bilingual broadcasts of Spanish and English can be distributed to two-way DA and DB.
[0033]
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In an embodiment of the present invention, for example, for sounds in the high range of 2500 Hz
(or 3000 Hz) or higher, array speakers 9a and 9b physically arranged in an array are used. The
array speakers 9a and 9b are very directional sharp sound sources, and have the characteristic
that when power is given in the same phase, sound pressure other than the front becomes very
low due to sound wave interference. Therefore, the directivity of each of the array speakers 9a
and 9b is matched with the directions DA and DB of FIG. 5 by the mid-bass speakers 5a and 5b of
the proximity control sound source as shown in FIG. And “Spanish” of the second channel can
be heard only in the listening areas of the desired directions DA and DB, respectively, even for
the high tone range. Therefore, according to the present invention, bilingual broadcasting can be
effectively distributed to two directions DA and DB for the whole range.
[0034]
In order to obtain sufficiently sharp directivity in an array speaker, the longitudinal dimension
for several wavelengths of the sound wave is required, and it becomes difficult for the mid-low
range to be within practical dimensions. Then, as described above, the PSC system is applied to
the mid-low range sound and the in-phase drive of the array speaker is applied to the high-range
sound, so the speaker mechanism can be downsized.
[0035]
[Other Configuration Example] In the present invention, not only the directional high-pitched
speakers 9a and 9b but also the mid-low pitched speakers 5a and 5b can be configured as array
speakers.
FIG. 7 is a block diagram showing the configuration of a directional loudspeaker according to
another embodiment of the present invention, and the same reference numerals as in FIG. 2
indicate the same configurations as in FIG. In this embodiment, the functions of the mid-low
range speakers 5a and 5b and the directivity high-tone speakers 9a and 9b of FIG. 2 are realized
by the array speakers SA and SB, thereby further simplifying the configuration of the speaker
device. Can. FIG. 8 is an external view of a directional loudspeaker according to another
embodiment of the present invention.
[0036]
In the example shown in FIGS. 7 and 8, the array speakers SA and SB are only driven in phase by
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the high frequency range acoustic signals of the first and second channels by the distribution
circuits 8a and 8b, respectively, with a predetermined intensity gradient. Instead, the output units
of the power amplifiers 4a and 4b are supplied via the adder circuit AD, and a part of the sound
generation units on the center side (the three units inside) are also driven by the PSC method.
When used together as an PSC driven speaker in an array speaker, the sounding unit on the
center side driven by the PSC method is eight minutes of the sound wave of the control
frequency band of the mid-bass component of the first and second channel acoustic signals A and
B. It is necessary to satisfy the interval of 1 wavelength to 1 wavelength, and depending on the
conditions, as shown in the development view of both speaker output surfaces in FIG. May not be
used.
[0037]
FIG. 9 (2) shows an example of another speaker apparatus configuration in which a part or all of
the array speaker used as the directional high-pitched speaker is shared with the mid-low range
speaker by the PSC system. Even in the array speakers SA and SB shown in FIG. 9 (2), all the tone
generation units are driven in phase with the high range acoustic signal with a predetermined
intensity gradient, and some tone generation units near the center are based on PSC method The
function of the mid-low range speaker is given.
[0038]
As described above, when both array speakers SA and SB are driven in phase with the first
channel and the second channel treble band acoustic signals respectively in phase, and in
addition, when PSC is driven with the middle bass sound signals, basically, , PSC midrange
acoustic signals use the inner unit of the array speaker, whereas PSC bass acoustic signals use
the outer unit of the array speaker. In the example of FIG. 9 (2), the function of the mid-low range
speaker is divided into the mid-range speaker unit SM and the low-range speaker unit SL, and the
mid-range speaker unit SM is located on the center side of the array speaker, The bass speaker
unit SL is located on the outside thereof. In this case, for example, the outputs of the power
amplifiers 4a and 4b of the sound source control device SC can be supplied to the medium sound
speaker unit SM and the low sound speaker unit SL through an appropriate filter.
[0039]
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Incidentally, the function of the mid-low range speaker for the mid-low range sound signal of the
PSC system can be divided not only into the above-described two ranges, but also into multiple
ranges more finely. Furthermore, it is not necessary to use all the sound generation units for the
high-range sound signal, and some sound generation units may be driven or not to be used by
the PSC method alone.
[0040]
[Other Embodiments] In the PSC system, the sound wave cancellation region (position, direction)
is, for example, the filter coefficient control already proposed by the present inventors (Japanese
Patent Application Nos. 11-101805 and 102110). No. 2), but such a filter coefficient control is
adopted in the sound source control apparatus of the present invention, and the arrangement
and directivity characteristic of high directivity speakers such as an array speaker are changed
accordingly. It can be configured.
[0041]
Also, the directional loudspeaker apparatus according to the present invention can consciously
create, in any direction or position, a region where the volume of a television broadcast, radio
broadcast, etc. is smaller than that in the same room, for example. .
It can be used as a speaker of a television audio multiplex broadcast receiver, and it is possible
for two people (or two groups) to simultaneously enjoy different voices of the main and auxiliary
channels of an audio multiplex broadcast such as bilingual broadcast. Regions can be consciously
created in any direction or position. In addition, it is not limited to broadcasting such as
television and radio, and is used for various directional loud-sounding systems in the case of
creating a small volume in a certain area or creating different areas in two areas indoors etc. be
able to.
[0042]
As described above, according to the present invention, two loudspeakers (5a, 5b) are separated
by an interval of 1/8 wavelength of sound wave of controlled frequency domain to 1 wavelength.
By arranging the sound wave of the mid-bass acoustic signal in this frequency region close to
each other and interposing the mid-bass cancellation control means between the acoustic signal
source and one of the speakers, In a certain area, mid-bass sound waves radiated from both
speakers are canceled by the interference between sound waves, and the high-range sound signal
of the sound signal source is avoided from the cancellation area from the directional high-tone
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speaker Since sound is emitted in the direction, it is difficult to hear both mid-low and highpitched sounds in the above-mentioned cancellation area and the listening area in the vicinity
thereof by using a small-sized speaker device. Door can be.
[0043]
Further, according to the present invention, two speakers are closely arranged via an interval of
1⁄8 wavelength of the sound wave of the frequency domain to be controlled to 1 wavelength, and
in this frequency domain, each content type is Mid-low range sound waves including the different
(uncorrelated) first channel and second channel acoustic signal components are emitted from
both speakers, and the second channel and first channel acoustic signal sources and the first and
second speakers In the meantime, by interposing the mid-bass cancellation control means, the
second channel of the mid-bass sound wave radiated from each speaker in the different first or
second regions in the listening spaces of both speakers respectively Alternatively, the first
channel acoustic signal component is canceled out by interference between sound waves, and the
high range acoustic signal of the first channel or second channel acoustic signal source can be
The speaker device is used to emit sound in a direction toward the region where the second
channel or first channel acoustic signal component of the mid-low range sound wave component
is canceled. In each of the listening areas in the area and its vicinity, it is possible to effectively
hear both the mid-bass range and the treble range of the separate sounds from the first channel
or second channel acoustic signal source.
[0044]
According to the present invention, with regard to mid-bass, the mid-bass cancellation control
means cancels each other out of the sounds emitted from the two speakers using the interference
of the sound waves, and for the high-pitch range, for directivity high-pitched By raising the sound
pressure level only in a specific direction toward the listening area using a speaker, separate
sound information can be effectively transmitted to a plurality of listening areas, including highpitched sound.
In addition, the directional high-tone speaker uses a high-directivity sound source such as an
array speaker to further effectively transmit separate sound information to each listening area
including the high-tone range with a simpler configuration. It can be realized.
[0045]
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15
Furthermore, according to the present invention, the mid-low range speaker is also included in
the array speaker, and part or all of the array speaker is driven as the mid-low range speaker via
the mid-low range cancellation control means. By using it, the speaker structure can be further
simplified.
In this case, the mid-low range speaker is divided into a mid-range speaker unit and a low-range
speaker unit, and the mid-range speaker unit is positioned on the center side of the array
speaker, and the low-range speaker unit is positioned outside thereof. Various effective methods
can be adopted depending on the situation.
[0046]
Brief description of the drawings
[0047]
FIG. 1 FIG. 1 is a diagram showing a prior art related to a directional loudspeaker.
[0048]
FIG. 2 is a block diagram showing a system configuration of a directional loudspeaker in
accordance with an embodiment of the present invention.
[0049]
3 is an external view of a directional loudspeaker system according to an embodiment of the
present invention.
[0050]
FIG. 4 FIG. 4 is a part of a view for explaining formation of a sound field by the proximity control
sound source in the present invention.
[0051]
FIG. 5 FIG. 5 is the other part of the diagram for explaining the formation of the sound field by
the proximity control sound source in the present invention.
10-05-2019
16
[0052]
FIG. 6 is a diagram for explaining formation of a sound field by a directional sound source in the
present invention.
[0053]
FIG. 7 is a block diagram showing a system configuration of a directional loudspeaker in
accordance with another embodiment of the present invention.
[0054]
FIG. 8 is an external view of a directional loudspeaker according to another embodiment of the
present invention.
[0055]
FIG. 9 is a view showing another example of the array speaker arrangement in another
embodiment of the present invention.
[0056]
Explanation of sign
[0057]
2 sound signal control circuit, 5a, 5b mid-bass speaker, 9a, 9b speaker for high-pitched sound,
ADC analog-to-digital converter, AT attenuator, AD addition (mixing) circuit, DAC digital-to-analog
converter, SC sound source controller, SA , SB Array speaker.
SM mid-tone speaker, SL bass speaker.
10-05-2019
17
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