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JP2008219228

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DESCRIPTION JP2008219228
PROBLEM TO BE SOLVED: To reduce resources for signal processing of an audio reproduction
apparatus using a speaker array. SOLUTION: A DSP 10 performs signal processing on an input
audio signal to generate a drive signal to each speaker unit SP of a speaker array 40. The CPU 50
causes the speaker array 40 to reproduce sound in a directivity pattern that is a mirror pattern
symmetrical with respect to a virtual plane which is a directivity pattern specified according to
the signal processing control program 61 and which includes an axis vertically penetrating the
center of the speaker array 40. Control to be performed. At this time, programs and parameters
to be executed by the DSP 10 are shared with the program memory 12 and the parameter
memory 13 by sharing at least a part of each process for obtaining each drive signal for the
speaker unit SP pair that forms mirror symmetry about the virtual plane Write to [Selected
figure] Figure 1
Sound reproduction device
[0001]
BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a
sound reproduction apparatus that performs sound reproduction by a speaker array.
[0002]
The speaker array is an acoustic output device in which a plurality of speaker units are arranged
in a one-dimensional array or two-dimensional array.
04-05-2019
1
The sound reproduction apparatus provided with this speaker array is provided with a signal
processing system which generates a drive signal to be given to each speaker unit from an input
audio signal. Here, as signal processing for generating a drive signal from an input audio signal, a
combination of delay processing and coefficient multiplication processing, FIR (Finite Impulse
Response; finite impulse response) filter processing, or the like is used. Then, according to this
sound reproducing apparatus, each drive to each speaker unit from the input audio signal is
controlled by controlling the delay amount of the delay processing and the coefficient of
coefficient multiplication processing, or controlling the filter coefficient sequence used for the
FIR filter processing. Each transfer characteristic to the signal can be controlled, and the
direction and the width of directivity of the acoustic wave radiated from the speaker array can be
controlled (for example, Patent Document 1). Unexamined-Japanese-Patent No. 5-41897
[0003]
By the way, in the above-mentioned conventional sound reproducing apparatus, signal
processing for obtaining drive signals for each speaker unit from input audio signals is
performed for all the speaker units constituting the speaker array, so the number of speaker
units is large. And resources required for signal processing, such as memory capacity for storing
parameters used for signal processing (for example, coefficients for coefficient multiplication
processing, filter coefficients for FIR filter processing, etc.) and operation capability for signal
processing. There was a problem that it would be huge.
[0004]
The present invention has been made in view of the above-described circumstances, and it is an
object of the present invention to provide a technical means capable of reducing resources
required for signal processing in an audio reproduction apparatus using a speaker array. There
is.
[0005]
The present invention comprises a speaker array in which a plurality of speaker units are
arranged in an array, signal processing means for applying signal processing to an input audio
signal to generate drive signals to be applied to the plurality of speaker units, and designated
directivity Means for controlling the signal processing means so that acoustic waves having a
pattern are emitted from the speaker array, wherein a mirror surface is a mirror plane of an
imaginary plane including an axis passing through a predetermined point of the speaker unit
arrangement surface in the speaker array When emitting acoustic waves having a symmetrical
04-05-2019
2
directivity pattern to the speaker array, speaker units having mirror symmetry with respect to
the virtual plane among the speaker units constituting the speaker array are grouped, and the
speakers of the same group are grouped. For each process to obtain each drive signal for the
unit, To provide an acoustic reproducing apparatus, wherein at least part of the processing of the
by sharing and control means for executing the signal processing means.
According to this invention, for the group of speaker units having mirror symmetry, at least a
part of the signal processing for obtaining the drive signal is shared among the speaker units, so
the total amount of signal processing is reduced.
Therefore, resources for signal processing can be reduced.
[0006]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings. FIG. 1 is a block diagram showing the configuration of a sound reproducing apparatus
1 according to an embodiment of the present invention. As shown in FIG. 1, the sound
reproduction device 1 includes a DSP (Digital Signal Processor) 10. Then, in the subsequent stage
of the DSP 10, an output sample register array 20 consisting of N (N is a plurality of) registers
for storing data output from the DSP 10, and D of each data stored in these N registers. N D / A
converters 31 for respectively performing N / A conversion, N amplifiers 32 for amplifying the
analog signals outputted from these D / A converters 31, and these amplifiers 32 A speaker array
40 is provided in which N speaker units SP are arrayed on a flat baffle surface.
[0007]
The DSP 10 receives an input audio signal from a sound source (not shown). The input audio
signal is a time-series sample string obtained by sampling and digitizing an analog audio signal
with a sampling clock of a predetermined sampling frequency. A main clock (not shown) having
the same frequency as the sampling frequency of the input audio signal is supplied to the DSP 10
and the N D / A converters 31.
[0008]
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In the present embodiment, the DSP 10 functions as a signal processing unit that performs signal
processing on an input audio signal to generate drive signals to be supplied to the N speaker
units SP. More specifically, the DSP 10 includes an operation unit 11, a program memory 12, a
parameter memory 13, and a work memory 14. Here, the program memory 12, the parameter
memory 13 and the work memory 14 are rewritable volatile memories, for example, RAMs. The
program memory 12 stores a program that the arithmetic unit 11 executes during one sampling
cycle (one cycle of the main clock). This program is a program for calculating N drive signal
samples respectively used for driving the N speaker units SP of the speaker array 40 based on
the input audio signal. The parameter memory 13 also stores various parameters (for example, a
filter coefficient sequence for the FIR filter) necessary for execution of the program in the
program memory 12. Arithmetic unit 11 starts the execution of the program in program memory
12 each time the main clock rises, refers to necessary parameters in parameter memory 13, and
makes each instruction constituting the program faster than the main clock. Run in
synchronization with the operation clock. At this time, the work memory 14 is used by the
operation unit 11 as a work area for storing an intermediate result of the operation.
[0009]
In each sampling cycle, operation unit 11 sequentially generates N drive signal samples
respectively used for driving N speaker units SP of speaker array 40 in accordance with the
program in program memory 12, and generates the generated drive signal samples. And write to
the corresponding register among the N registers of the output sample register array 20. The N D
/ A converters 31 simultaneously convert the N drive signal samples stored in the output sample
register array 20 into analog signals in synchronization with the main clock in each sampling
cycle. These N analog signals are provided to the N speaker units SP of the speaker array 40 via
the N amplifiers 32. Thereby, an acoustic wave corresponding to the input audio signal is emitted
from the speaker array 40.
[0010]
Furthermore, the sound reproduction device 1 according to the present embodiment has a CPU
50, a ROM 60, and a RAM 70. The CPU 50 is a device that controls the entire sound reproduction
device 1. The ROM 60 stores various programs executed by the CPU 50 to control the respective
units of the sound reproducing apparatus 1 and various information referred to when the
programs are executed. The RAM 70 is used by the CPU 50 as a work area.
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[0011]
Among the information stored in the ROM 60, there are a signal processing control program 61,
a subroutine library 62, and speaker array information 63. Directivity pattern designating
information for designating a directivity pattern of acoustic waves radiated from the speaker
array 40 is given to the CPU 50 from a host computer (not shown). When the CPU 50 receives
the directivity pattern designation information, the CPU 50 executes the signal processing
control program 61 in the ROM 60, and an acoustic wave having a directivity pattern designated
by the directivity pattern designation information is emitted from the speaker array 40.
Functions as control means for controlling the DSP 10 as signal processing means.
[0012]
More specifically, the signal processing control program 61 has a directivity pattern indicated by
the directivity pattern indication information as a program and parameters for generating drive
signal samples for the N speaker units SP from the input audio signal. It is a program that
generates a program and parameters that can emit the acoustic wave from the speaker array 40
and causes the CPU 50 to execute the process of writing the program memory 12 and the
parameter memory 13.
[0013]
The subroutine library 62 is a collection of subroutines such as a subroutine for FIR filter, a
subroutine for EQ (equalizer), etc., which generate a program to be written to the program
memory 12 by the signal processing control program 61.
The speaker array information 63 is information indicating the arrangement of the speaker units
SP in the speaker array 40, the characteristics of the speaker units SP, and the like, and is
referred to when the signal processing control program 61 generates a program or parameters
written to the program memory 12. Ru.
[0014]
As described above, under the prior art, signal processing for obtaining a drive signal for each
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speaker unit from input audio signals was performed for all the speaker units constituting the
speaker array. For this reason, the number of instruction steps that the DSP must execute during
one sampling period increases in proportion to the number of speaker units, and parameters
such as filter coefficients used to execute those instructions are also speaker units There is a
problem that it increases in proportion to the number of The object of the present embodiment is
to reduce resources for signal processing, that is, to halve the number of instruction steps that
the DSP 10 has to execute during one sampling period, and also to halve the parameters used to
execute the instructions. It is to let
[0015]
In the present embodiment, this object is achieved by the following means. a. The directivity
pattern of acoustic waves radiated from the speaker array 40 is restricted. That is, in the present
embodiment, an acoustic wave having a directivity pattern that is mirror-symmetrical with
respect to a virtual plane including an axis vertically penetrating the center of the speaker array
40 is emitted from the speaker array 40. However, the directivity pattern may be mirror
symmetric with respect to the virtual plane, and a representative axis of the directivity pattern
with respect to an axis vertically penetrating the center of the speaker array 40 (specifically, an
axis directed to the main lobe) The angle of may be any angle. b. About each process for
obtaining each drive signal sample with respect to two speaker units SP which make mirror
symmetry about a virtual plane including an axis which penetrates the center of speaker array
40 perpendicularly, at least one copy of those processes is shared The signal processing means is
executed by the DSP 10. That is, the signal processing control program 61 generates a program
and parameters for causing the DSP 10 to execute such partially shared signal processing, and
writes the program and parameters in the program memory 12 and the parameter memory 13.
[0016]
Further, in the present embodiment, in order to enhance the effect of resource reduction
described above, the speaker array 40 having symmetry with respect to the arrangement of the
speaker units SP is adopted, and a virtual plane of which directivity pattern is mirror symmetric
is Restrict to those in the range consistent with the symmetry of the SP arrangement. The details
will be described below.
[0017]
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6
FIGS. 2A to 2D are diagrams showing an arrangement example of the speaker units SP in the
speaker array 40 suitable for the present embodiment. In the speaker array 40 shown in FIG. 2A,
the speaker units SP are arranged in mirror symmetry. Moreover, in each speaker array 40
shown in FIG.2 (b)-(d), each speaker unit SP is arrange | positioned so that rotation symmetry
may be made. 2 (b) is an example of six-fold symmetry, FIG. 2 (c) is an example of two-fold
symmetry, and FIG. 2 (d) is an example of four-fold symmetry. If the arrangement of the speaker
units SP in the speaker array 40 is mirror symmetric or rotationally symmetric as in these
examples, the effect of resource reduction can be enhanced while enhancing the variation of the
directivity pattern.
[0018]
FIGS. 3A to 3D illustrate the symmetry and directivity of the arrangement of the speaker units SP
in the present embodiment, taking the case where the speaker units SP are arranged in the
speaker array 40 so as to form six-fold symmetry. It shows the relationship with the symmetry of
the pattern.
[0019]
In the case where the arrangement of the speaker units SP is six-fold symmetric, a virtual plane
which bisects each speaker unit SP such that each speaker unit SP has mirror symmetry is
included in total including an axis vertically penetrating the center of the speaker array 40 Six
sides can be provided.
In FIGS. 3A to 3D, their imaginary planes are shown by broken lines.
[0020]
In the present embodiment, the directivity pattern requires that the speaker units SP of the
speaker array 40 be mirror symmetric with respect to one of a plurality of mirror symmetric
surfaces forming mirror symmetry. In the example shown in FIG. 3A, the speaker array 40 emits
an acoustic wave having a directivity pattern DP in which the mirror symmetry plane P1 is a
mirror symmetry plane among the mirror symmetry planes of six planes of the speaker array 40.
There is. In the example shown in FIGS. 3B to 3D, the speaker array 40 generates acoustic waves
of directivity patterns DP in which the mirror symmetry planes P2, P3 and P4 of the speaker
04-05-2019
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array 40 different from this are mirror symmetry planes. Is emitting
[0021]
The following advantages can be obtained by setting the above restrictions. That is, for example,
as shown in FIG. 3A, when the acoustic wave of the directivity pattern DP which is mirror
symmetric with respect to the mirror symmetry plane P1 of the speaker array 40 is emitted to
the speaker array 40, the mirror symmetry plane P1 The group of symmetrical speaker units SP,
for example, the group of speaker units SP1a and SP1b in FIG. 3A, the group of speaker units
SP2a and SP2b, etc., provide the same drive signal to two speaker units in each group. Become.
With regard to the two speaker units SP constituting such a group, if the drive signal sample to
be supplied to one speaker unit SP is calculated, the drive signal sample can be used to drive the
other speaker unit SP. That is, signal processing (more specifically, a program and parameters for
signal processing) for obtaining drive signal samples can be shared between two speaker units SP
configuring the same group. The present embodiment utilizes this point to reduce resources for
signal processing.
[0022]
FIG. 4 and FIG. 5 are diagrams showing the processing content of the signal processing control
program 61 in the present embodiment. The signal processing control program 61 refers to
directivity pattern designation information and the speaker array information 63 in the ROM 60
as shown in FIG. 4 when generating a program and parameters to be written to the program
memory 12 and the parameter memory 13.
[0023]
In a preferred embodiment, the directivity pattern designation information includes mirror
symmetry plane designation information, radiation angle information, and wavefront designation
information. Here, the mirror surface symmetry plane designation information is information
specifying the mirror surface symmetry plane in which the directivity pattern is mirror plane
symmetry among the one or a plurality of mirror plane symmetry surfaces in which the
arrangement of the speaker units SP is mirror plane symmetry in the speaker array 40. is there.
Further, in the radiation angle information, the representative direction (for example, the
direction of the main lobe) of the directivity pattern is with respect to the axis passing through
04-05-2019
8
the center O of the speaker array 40 in the mirror symmetry plane where the directivity pattern
is mirror symmetry. This is information for specifying the angle φ to be made (see above, FIG. 5).
The wavefront designation information is information for identifying the wavefront shape of the
acoustic wave emitted from the speaker array 40. For example, in the case of emitting an
acoustic wave that converges to a focal point in front of the speaker array 40, information
indicating the relative position of the focal point viewed from the center O of the speaker array
40 is used as this wavefront designation information. In addition to the information indicating
the position of the speaker unit SP in the speaker array 40, the speaker array information 63 is a
mirror surface of each of one or a plurality of mirror symmetry surfaces in which the
arrangement of the speaker unit SP is mirror symmetric in the speaker array 40. It includes
grouping information that designates a group of speaker units SP that are mirror-symmetrical
with respect to a plane of symmetry.
[0024]
The signal processing control program 61 executes the grouping processing 61a based on the
mirror symmetry plane designation information in the directivity pattern designation information
given from the host computer and the grouping information in the speaker array information 63
(see FIG. 4). . More specifically, the mirror surface symmetry plane in which the directivity
pattern is mirror plane symmetric is determined based on the mirror plane symmetry plane
designation information, and the group of speaker units SP in mirror symmetry with respect to
the mirror plane symmetry plane is calculated based on the grouping information. is there.
[0025]
Then, in the signal processing control program 61, for each of the groups obtained by the
grouping processing 61a, a processing 61b for generating a program and parameters for
calculating a drive signal sample to be commonly used for the two speaker units SP is executed. ,
Programs and parameters are written to program memory 12 and parameter memory 13 (see
FIGS. 4 and 5).
[0026]
In addition, since there is no speaker unit SP which becomes the other side of mirror symmetry,
the speaker unit SP which a mirror symmetry plane crosses can not comprise a group.
04-05-2019
9
Therefore, in the signal processing control program 61, such a speaker unit SP is handled alone,
and a program and parameters for calculating a drive signal sample for the speaker unit SP are
generated to generate the program memory 12 and the parameter memory 13. Write.
[0027]
In the program and parameter generation process 61b, radiation angle information or wavefront
designation information in directivity pattern designation information and information indicating
the position of each speaker unit SP in the speaker array information 63 are referred to. For
example, when the wavefront designation information designates radiation of an acoustic wave
that converges to a certain focal point, in the program and parameter generation processing 61b,
the focal point from each loudspeaker unit SP is based on the information indicating the position
of each loudspeaker unit SP. Find each distance up to. Then, as an optimal value of each delay
amount between the input audio signal and the drive signal sample addressed to each speaker
unit SP, the delay amount capable of causing the acoustic wave emitted from each speaker unit
SP to reach the focal point in the same phase And generate programs and parameters that cause
such delays. In that case, it is not necessary to perform such an operation for all the speaker
units SP, and for the two speaker units SP in the same group, if the necessary delay amount is
calculated for one of the speaker units SP, Good. This is because the same result can be obtained
even if the calculation for calculating the delay amount is performed for the other speaker unit
SP. The same applies to parameters other than delay, such as gain by which the delayed audio
signal sample is multiplied to obtain each drive signal sample. Note that instead of referring to
the wavefront designation information, referring to the radiation angle information, an acoustic
wave having the direction of the main lobe in the direction of the angle φ indicated by the
radiation angle information in the mirror symmetry plane indicated by the mirror symmetry
plane designation information The contents of the program and parameters for obtaining the
drive signal sample of each speaker unit SP may be determined so as to be emitted from the
speaker array 40.
[0028]
In FIG. 4, the program for signal processing corresponding to each group corresponds to the two
speaker units SP belonging to the group among the N registers in the output sample register
array 20 for the drive signal sample calculated in the program. The final process includes the
process of writing the two registers. In addition, a program for signal processing corresponding
to a single speaker unit SP writes the drive signal sample calculated in the program into a
register corresponding to the speaker unit SP among N registers in the output sample register
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array 20. Is included as final processing. The program and parameter generation process 61b
generates an instruction for this final process as a part of a signal processing program
corresponding to each group.
[0029]
6 to 8 show specific contents of programs and parameters written to the program memory 12
and the parameter memory 13 by the signal processing control program 61, that is, specific
examples of signal processing executed by the DSP 10 according to the programs and
parameters. It is a thing.
[0030]
In the example shown in FIG. 6, the signal processing control program 61 divides each speaker
unit SP of the speaker array 40 into a first group consisting of the speaker units SP1a and SP1b,
a second group consisting of the speaker units SP2a and SP2b, etc. For each group, programs
and parameters for executing the FIR filter 101-j (j is a group number) are generated as signal
processing for obtaining drive signal samples from the input audio signal.
The contents of the filter coefficient sequence of the FIR filter are determined based on the
relationship between the position of the speaker unit SP and the directivity pattern. Thus, the
content of the filter coefficient sequence of the FIR filter is generally different between the
groups. FIR filter 101-k and subsequent FIR filters are signal processing for a single speaker unit
in which there is no mirror symmetric partner.
[0031]
In the example shown in FIG. 7, the signal processing control program 61 multiplies the sampling
period Ts by the integer n as signal processing for obtaining drive signal samples from the input
audio signal for each group of speaker units SP forming mirror symmetry. Sample delay
processing 111 for delaying the input signal by delay time, Fractional multiple delay processing
112 for delaying the input signal by delay time obtained by multiplying sampling period Ts by
fraction α, multiplication processing for multiplying the input signal by gain G Programs and
parameters for executing signal processing 110-j (j is a group number). The integer n, the
fraction α and the gain G are generally different between different groups. The signal processing
after the signal processing 110-k is signal processing for a single speaker unit in which there is
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no mirror symmetric partner.
[0032]
In the example shown in FIG. 8, each speaker unit SP of the speaker array 40 is divided into a
speaker unit SPL for low frequency output and a speaker unit SPH for high frequency output.
Here, since the low-frequency output speaker unit SPL and the high-frequency output speaker
unit SPH have different frequency characteristics of loss during conversion from an electrical
signal to air vibration and frequency characteristics of acoustic radiation, the input is different. It
is necessary to change the content of signal processing to obtain drive signal samples from the
audio signal. Therefore, in this example, the signal processing control program 61 divides each
speaker unit SP of the speaker array 40 into a large group of speaker units SPL for low
frequency output and a large group of speaker units SPH for high frequency output. An LPF
process 201 is generated to select the low frequency component of the input audio signal for the
large group, and an HPF process 202 is generated to select the high frequency component of the
input audio signal for the latter large group. In order to enable such processing, in the speaker
array information 63 to which the signal processing control program 61 refers, for each speaker
unit SP of the speaker array 40, whether each is a speaker unit SPL for low frequency output or
high Information indicating the speaker unit SPH for range output may be included.
[0033]
The signal processing control program 61 then divides the large group of low-pass output
speaker units SPL into small groups of two speaker units that form mirror symmetry with respect
to the same plane as the mirror symmetry plane of the directivity pattern (an example shown in
FIG. Then, it is divided into groups of speaker units SPL1a and SPL1b, etc.) and signal processing
210L-j consisting of EQ 211, sample delay processing 212, fractional multiple delay processing
213, and multiplication processing 214 for each small group thereof. (J is a group number) is
generated. In addition, the signal processing control program 61 further comprises a large group
of speaker units SPH for high frequency output, and a small group of two speaker units forming
mirror symmetry with respect to the same plane as the mirror symmetry plane of the directivity
pattern Then, the signal unit 210H is divided into the speaker unit SPH1a and the group SPHb,
etc.) and signal processing 210H-j consisting of EQ 211, sample delay processing 212, fractional
double delay processing 213, and multiplication processing 214 for each small group thereof. (J
is a group number) is generated. In each of the low band and high band large groups, the signal
processing of the signal processing 210 L-k onward and the signal processing 210 H-k is signal
processing for a single speaker unit in which there is no mirror symmetric partner.
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[0034]
Here, the EQ 211 is a combination of the following three EQs. a. A first EQ for compensating
for the frequency characteristics of the loudspeaker unit SP itself (frequency characteristics of
loss in conversion from electrical signal to air vibration and frequency characteristics of acoustic
radiation). b. A second EQ to compensate for differences in frequency characteristics
dependent on the distance relationship between the position of the loudspeaker unit SP and the
control point (such as the focal point of the acoustic wave). c. A third EQ for compensating for
differences in frequency characteristics depending on the directional relationship between the
position of the speaker unit SP and the control point (such as the focal point of the acoustic
wave).
[0035]
Among the first EQs, the contents of the first EQ greatly differ between those corresponding to
the low-pass output speaker unit SPL and those corresponding to the high-pass output speaker
unit SPL. Also, the second and third EQs are generally different between the groups of speaker
units SP. For this reason, in the example shown in FIG. 8, the EQ 211 is generated for each small
group obtained by further dividing each large group for low band output and high band output
based on mirror symmetry. The differences between the small groups in the processing contents
of the delay processing 212 and 213 and the multiplication processing G are the same as in the
example of FIG. 7 described above.
[0036]
As described above, according to the present embodiment, the amount of signal processing for
obtaining the signal for driving each speaker unit SP of the speaker array 40 can be halved as
illustrated in FIGS. it can. Further, according to the present embodiment, the amount of signal
processing can be halved, so the amount of programs and parameters that are generated for the
signal processing and stored in the memory can be halved. Therefore, according to the present
embodiment, resources for signal processing can be reduced.
[0037]
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As mentioned above, although one Embodiment of this invention was described, other
embodiment besides this can be considered to this invention. For example:
[0038]
(1) In the speaker array 40, the baffle surface on which each speaker unit SP is disposed may be
a curved surface.
[0039]
(2) It is not necessary that all of the plurality of speakers SP in the speaker array 40 have mirror
symmetry.
Even if some of the plurality of speakers SP do not have mirror symmetry with another speaker
unit SP with respect to a certain mirror symmetry surface, if the other speaker units SP have
mirror symmetry, the mirror symmetry surface When the acoustic wave of the directivity pattern
which makes mirror symmetry with respect to the same plane as the above, it is possible to share
signal processing and reduce resources for the group of speaker units SP which make mirror
symmetry.
[0040]
(3) Although two or more types of speaker units SP having different shapes and characteristics
may be mixed in the speaker array 40, the speaker units SP constituting the same group have the
same type and the same shape and characteristics. It is preferred that Therefore, when the
speaker array 40 includes two or more types of speaker units SP, the speaker array information
63 may include speaker type identification information indicating the shape and characteristics
of each speaker unit SP of the speaker array 40. . In this aspect, in the grouping processing 61a
of the speaker units SP, when there is a group of two speaker units SP that are mirror targets, the
signal processing control program 61 uses the speaker type identification information of each
speaker unit SP as the speaker array. It is extracted from the information 63 and it is determined
whether or not both speaker type identification information are the same. Then, only when the
speaker type identification information of the two speaker units SP is the same, the speaker units
SP are grouped, and otherwise, each speaker unit SP is not grouped but a single speaker It is
04-05-2019
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treated as a unit SP.
[0041]
(4) It is not necessary to group all the mirror-symmetrical speaker units SP. For example, a
specific speaker unit SP may be configured to be handled alone without being grouped.
[0042]
(5) In the above embodiment, the program and parameters for signal processing are shared for
the two speaker units SP in the same group, but the program is provided for each speaker unit SP
and the parameters used by the program are 2 The speaker units SP may be shared.
[0043]
(6) In the above embodiment, the CPU 50 calculates the parameters such as the delay amount,
the gain, and the filter coefficient sequence used for signal processing executed by the DSP 10
according to the signal processing control program 61 by arithmetic processing.
However, these parameters may be generated by table reference processing instead of such
arithmetic processing.
That is, various directivity patterns of acoustic waves radiated by the speaker array 40 are
determined in advance, and a delay amount necessary for signal processing for emitting acoustic
waves having the directivity patterns for each of the directivity patterns, Parameters such as gain
and filter coefficient sequence are calculated in advance, and stored in, for example, the ROM 60
in association with an identifier for specifying a directivity pattern. When the directivity pattern
instruction information is provided from the host computer (in this case, the host computer may
provide the identifier of the directivity pattern as directivity pattern instruction information), the
CPU 50 uses the directivity pattern instruction information. The parameters associated with the
instructed directivity pattern may be read out from the ROM 60 and used for signal processing.
[0044]
(7) When an acoustic wave having a directivity pattern is emitted from the speaker array 40, the
host computer generates a program and parameters used for signal processing therefor, and the
program memory 12 and parameter memory in the sound reproducing apparatus 1 It may be
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written in 13.
[0045]
(8) In the above (7), the sound reproduction device 1 may be provided with a cache memory for
storing a program and parameters used for signal processing together with the directional
pattern identifier.
The cache memory is desired to have a capacity capable of storing programs and memories
corresponding to some kind of directivity patterns. In this aspect, when the CPU 50 receives
certain directional pattern designation information (a directional pattern identifier) from the host
computer, if the corresponding program and parameter are in the cache memory, the program
and the parameter are stored in the program memory. 12 and write to parameter memory 13 If
the program and parameters corresponding to the directivity pattern instructed by the directivity
pattern indication information are not in the cache memory, the CPU 50 requests the program
and parameters from the host computer, whereby the program and parameters supplied from the
host computer Are written to the program memory 12 and the parameter memory 13 and to the
cache memory. At that time, the frequency of use of programs and parameters corresponding to
each directivity pattern in cache memory (frequency of writing to program memory 12 and
parameter memory 13) is managed, and when the cache memory is about to overflow, the
frequency of use is Control may be performed to evict the lowest program and parameters from
the cache memory.
[0046]
(9) In the above embodiment, each DSP 10 is used to sequentially execute programs for
obtaining a drive signal of a group of speaker units SP or a single speaker unit SP during one
sampling period. However, when there are a plurality of DSPs 10 in the sound reproduction
device 1, the program to be executed during one sampling period may be divided, and each of
the divided programs may be executed by the plurality of DSPs 10.
[0047]
It is a block diagram which shows the structure of the sound reproduction apparatus 1 which is
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one Embodiment of this invention. It is a figure which shows the example of arrangement |
positioning of speaker unit SP suitable for the embodiment. It is a figure which shows the
relationship between the symmetry of arrangement | positioning of speaker unit SP in the
embodiment, and the symmetry of a directivity pattern. It is a figure which shows the processing
content of the signal processing control program 61 in the embodiment. It is a figure which
shows the processing content of the signal processing control program 61 in the embodiment. It
is a block diagram which shows the 1st example of the signal processing performed by DSP10 in
the embodiment. It is a block diagram which shows the 2nd example of the signal processing
performed by DSP10 in the embodiment. It is a block diagram which shows the 3rd example of
the signal processing performed by DSP10 in the embodiment.
Explanation of sign
[0048]
10: DSP, 40: speaker array, SP: speaker unit, 50: CPU, 60: ROM, 61: signal processing control
program, 62: subroutine library, 63: speaker array information, 11: ... ... arithmetic unit, 12 ...
program memory, 13 ... parameter memory.
04-05-2019
17
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