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JPH0970092

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JPH0970092
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
point source non-directional speaker system that radiates a well-focused sound wave in the space
around the entire speaker system in a spherical shape. The present invention relates to a speaker
system capable of stereoscopically depicting the presence of individual sound sources, such as
human voices and musical instruments, contained therein.
[0002]
2. Description of the Related Art When a tuning fork is struck and vibrated, the vibration of air
originating from the tuning fork spreads in a spherical shape in a four-dimensional space
centered on the tuning fork. That is, at a position on the space equidistant from the tuning fork,
the sound emitted from the tuning fork can be heard with substantially the same sound pressure
in any direction, so the sound wave emitted from the struck tuning fork is diffused as a spherical
wave I understand that Now, when the sound of the tuning fork is collected and recorded with a
microphone and reproduced with a conventional speaker system in which a speaker unit is
disposed on one side of a hexahedron (a rectangular enclosure), the front of the speaker unit is
recorded. The sound pressure is high only, the surrounding area is low, and the tuning fork
spherical wave is not reproduced.
[0003]
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Conventionally, the speaker system has been used to reproduce music, expand speech such as
speech, and reproduce natural sounds and sound effects in movies etc., but as a sound source to
be reproduced from the speaker unit Many of the sounding bodies included are omnidirectional
and emit spherical waves like percussive instruments and woodwinds, and even if the
pronunciation part is one side of the instrument like stringed instruments, body noise is
important Since it can be regarded as a virtually omnidirectional sounding body because it acts
as a sound quality element, most of the sounding body may be considered to emit an
omnidirectional spherical wave. On the other hand, the sense of the human ear determines the
direction of the sound source by the direct sound that can be reached at the shortest distance
from the instrument, and compares the information of indirect sound from surrounding
reflectors such as the floor, wall and ceiling with the experience value of the brain Then, it is seen
to experience the distance to the musical instrument, that is, the sound source, the presence of
the musical instrument, and the sense of reality. Some brass instruments, such as trumpet, have
extremely different timbres before and after the instrument, that is, they have strong directivity.
In such a highly directional instrument, the timbre of the front is generally the sound of the
instrument, and since it is close to the sounding form of the unidirectional speaker system, the
nondirectional and point sound source speaker system is not suitable However, in the case of
sounds played by a speaker system in which the appearance of the performer can not be seen, a
person who listens to the reproduced sound recognizes the existence of the trumpet or the sound
emitted from it. In order to do so, we need information on the sense of distance by indirect
sound. In order to faithfully reproduce the sound source as described above, that is, the sound
source sounding in a variety of manners, a point sound source that exhibits excellent
characteristics even in the reproduction of a single directivity / high directivity instrument sound
An omnidirectional, spherical wave speaker system is preferable. The reason is as follows.
[0004]
(A) In the most common unidirectional speaker system, in which the speaker unit is attached to
one side of a six-sided enclosure, the correct instrument sound can be detected only in the front
direction of the system. It is equivalent to emitting and emitting another sound corresponding to
the indirect sound source in directions other than the front. As a result, two different musical
instruments, direct sound and indirect sound, exist at the position of the sounding body, and a
subtle deviation of the auditory sensation image makes it impossible to form a realistic sound
image in human hearing. . (B) In view of this point, a speaker system in which a speaker unit is
uniformly mounted on the surface of a polyhedron or a sphere is newly proposed as JP-A-6205490, etc., and it is partially used for practical use. There is something that In addition, a
report on "a nondirectional speaker" is also published in "JAS JOURNAL 'September 1993 issue".
However, in the case of a conventionally known spherical wave radiation type speaker system in
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which a speaker unit is disposed on a polyhedron or a spherical body, it is known that a peak and
a dip occur in the frequency response. There is a disadvantage that the system can not be driven
as a high-fidelity speaker system unless corrections are made. (C) On the other hand, it is known
that, if the defect of frequency response is compensated in the conventional analog technology, it
causes phase distortion, but in order to clarify the relationship between this phase distortion and
audibility, correction using an analog equalizer There is an experimental report on For example,
“phase and sound quality” published in “AES Tokyo Convention '95 Preliminary Collection”
is one of them. However, in the analog processing, it is difficult to exactly correct the sound
pressure level, and the phase response is deteriorated due to the correction of the frequency
response, so that a clear sound image is obtained in the conventional analog technology
nondirectional speaker system. It is said that I can not do it. (D) On the other hand, a speaker
system which generates a pseudo-spherical wave by using a round reflector is also
conventionally proposed as a kind of omnidirectional speaker. However, since the speaker
system causes deterioration of the frequency response and the phase response due to the
reflection plate, the corresponding cancellation process is required, but the speaker system does
not take this point into consideration. The basic performance of an omnidirectional speaker, ie,
reproduction of a sound source, has not been realized. (E) Recently, Digital signal processor,
hereinafter the same.
), And Realtime digital signal processing (the same below). (6) has attempted to flatly correct the
frequency response and phase response of a speaker system using a hollow hexahedron
enclosure. However, this is also an attempt to apply digital signal processing to a multi-waist
picker unit set in a conventionally known hollow hexahedron enclosure, and the speaker system
itself is a mechanism for producing natural sound. We have not studied a speaker system that
can realize point sound sources, omnidirectionality, and spherical waves. (F) The real-time digital
signal processing unit using a digital signal processor as described above is commercialized as a
single digital equalizer, but using the digital equalizer, a speaker system with a digital equalizer is
used. Become a block diagram of FIG. When the speaker system of FIG. 6 is used as an example
for a public address system etc., there are the following problems. Generally, in the public
address system, the analog attenuator 13 is installed at the monitor output of the mixing console
operated by the mixing engineer, and the volume control operates this attenuator 13. . When the
speaker system shown in FIG. 6 is used for high-fidelity audio, the attenuator 13 is installed in a
control amplifier operated by a listener to control the volume in the same manner. On the other
hand, in the speaker system of FIG. 6, the analog attenuator 14 inserted in front of the power
amplifier 17 is often half-fixed for the purpose of presetting the input gain of the power amplifier
17. If the analog attenuator 14 is set so that the output sound of the speaker unit 18 is not
distorted by power, the analog attenuator 13 at the front stage of the input system is used in the
normal use state where it is used at a smaller volume. Since the volume is lowered, the input
signal level to the A / D converter 15 becomes small, and the A / D converter 15 can not perform
accurate analog-to-digital conversion. As a result, the digital equalizer 16 that handles input
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signals with small levels has a problem that calculation errors are accumulated in the process of
signal processing, causing negative effects such as increase in noise and deterioration in
distortion factor. In order to solve the above problems, the master engineer / attenuator 20 is
placed at the mixing engineer's hand, and a special signal line 21 for level control signal is
provided in addition to the audio signal line, and the analog attenuator 14 is It is conceivable that
it could be used in practice.
As an example of applying this to a system using a plurality of speaker units in parallel, such as a
public address, the configuration is as shown in the block diagram of FIG. However, when the
speaker system becomes large like this, the volume control does not work for only one channel
when it is necessary to lower the volume at the end of the music, for example, due to a contact
failure of the connector or the like. There is a problem that an accident that the volume of the
speaker unit 18 of the channel does not decrease easily occurs.
[0005]
As mentioned above, when we look at the sound generation mechanism of musical instruments
and natural sounds reproduced by the speaker system, there are many non-directional sounding
bodies, and the auditory sense of the person on the listening side makes the presence of the
sound source Considering that it is clearly grasped, it can be said that the point sound source /
nondirectional / speaker system is an ideal sounding body in order to more faithfully reproduce
the sound emitted by the sound source. In addition, although the concept of a breathing sphere is
conventionally known, in the speaker system as well, if the entire surface of the sphere is
uniformly expanded or contracted to transmit the vibration of the sound wave to the air, the
sound can be reproduced. It is possible to hear the reproduced sound in the same manner as an
instrument or natural sound generating mechanism that can hear equal sound pressure if it is
equidistant from the speaker system. However, there is no point sound source nondirectional
speaker system which can reproduce the wide band of about 20 Hz to 20 KHz required by the
audio system in the form of a breathing sphere.
[0006]
Therefore, the problem to be solved by the present invention is to combine a conventionally
known unidirectional directivity speaker unit in order to form a sound producing body of an ideal
reproduction sound. Although it is used, devising the arrangement of the speaker unit to be used
and the peak and dip of the frequency response and the phase response which can not be solved
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only by the arrangement of the speaker unit can be realized by the digital signal processor. By
applying time digital signal processing to the speaker unit to reversely correct the peaks and dips
and eliminating them, it is possible to give a reproduced sound that vibrates in the state close to
the breathing sphere to human hearing. To provide a power system. In addition, an analog level
controller which is necessary for practical use, for example, an analog attenuator incorporates
this after a D / A converter of an input signal line, and a special signal for a control signal of the
attenuator. Optimal operation of real-time digital signal processing without adding lines is also
part of the problem of the present invention.
[0007]
SUMMARY OF THE INVENTION The configuration of the point sound source non-directional
speaker system of the present invention made for the purpose of solving the above problems is
twelve pentagonal planes and twenty hexagonal planes. A hollow icosahedron consisting of flat
surfaces is used as the basic structure of the enclosure, and the speaker units are disposed on all
32 surfaces, or 25 to 31 surfaces, and the above-mentioned speaker units are produced. In order
to flatten the frequency and phase response peaks and dips, filtering of the reverse characteristic
to the drive signal of the speaker unit is performed by the real time digital signal processing unit
inserted in the input system of the speaker unit. It is characterized in that it is carried out.
[0008]
Further, in the above-described speaker system of the present invention, a hollow body of 32
faces made up of 12 planes of pentagons and 20 planes of hexagons is used as a basic structure
of the enclosure, and is formed of pentagons. Arrange the speaker unit for the low frequency
range or the middle or low range on the 12 to 9 side, and arrange the speaker unit for the middle
or high range on the 20 to 15 side composed of a hexagonal shape Thus, a speaker unit group in
which a plurality of mid-high range or high-range speaker units are disposed around each lowrange or middle-low range speaker unit is a spherical surface. Being placed on the body or
polyhedron in a well-balanced manner, it is possible to further extend the reproduction
bandwidth of the sound around the entire circumference of the speaker body.
[0009]
Furthermore, in the above-described speaker system of the present invention, D / A conversion is
performed by multiplexing control data for volume control into SPDIF or AES / EBU signal of
digital audio interface standard. A real-time digital signal by sending to a block and increasing or
decreasing the level of the analog signal after D / A conversion so that the calculation accuracy
of the real-time digital signal processing unit can always be kept in the best state. The calculation
accuracy of the processing unit can be kept in the best state, and the information possessed by
the sound source can be reproduced from the speaker system without distortion.
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[0010]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The preferred balanced
polyhedrons for use in the speaker system of the present invention are regular dodecahedrons,
regular icosahedrons, and 32-faces, 180 faces and the like consisting of pentagonal faces and
hexagonal faces. However, in the speaker system according to the present invention, the speaker
enclosure is preferably a hollow icosahedron or a polyhedron having a polyhedron close to it or
the like, in order to give the human a sense of hearing equivalent to a spherical wave by a
breathing sphere. .
Further, in the speaker system of the present invention, from a practical point of view, the
relative positional relationship between the user in charge of the low frequency range and the
tweeter in charge of the middle and high range by the minimum number of faces of 32 faces, and
It is the speaker system of the present invention which will be described in the examples that the
optimum order values of their relative arrangements are determined through experiments.
In the speaker system of the present invention using a hollow 32-faced enclosure as viewed from
the point of sound reception, the enclosure should be disposed so that the pentagonal surface
faces the upper and lower surfaces. desirable.
This point is the same as in the case of using a spherical body assuming a pentagonal surface and
a hexagonal surface as the enclosure.
[0011]
Next, an embodiment of the speaker system of the present invention will be described with
reference to the drawings. In the speaker system according to the present invention, a hollow
icosahedron whose outer surface is composed of 12 planes 1 of pentagons and 20 planes 2 of
hexagons is enclosed by an enclosure EC (speaker cabinet or The basic structure of the speaker
box (also referred to as a “speaker box”), all of the 12 faces 1 composed of pentagons, or 11 to
9 faces of the pentagonal face 1 from a practical point of view -The speaker unit 7 is disposed,
and the speaker unit 8 for the middle to high range is disposed on all 20 faces configured with a
hexagonal shape, or 19 to 15 from a practical point of view. Configure What is illustrated in FIGS.
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1 and 2 is an example in which a so-called full range type speaker unit 78 is disposed on each of
the surfaces 1 and 2 described above.
[0012]
The speaker body having the speaker units 7 and 8 or 78 disposed in a 32-sided body as
described above, when this is driven as it is, as shown schematically in FIG. 4 and dip 5 occur. In
the present invention, the digital signal processor 6 (hereinafter referred to as DSP 6) exemplifies
the correction as shown in FIG. 4 in order to substantially flatten such distortion appearing in the
peak 4 and the dip 5. Inverse filtering is performed on the drive signal of each speaker unit 78 or
7 and 8. In FIG. 4, 9 is a digital input signal input to the DSP 6, 10 is a D / A converter block, 11
is a power amplifier, 12 is an operation panel attached to the DSP 6, and 100 is inserted in front
of the power amplifier 11. Analog attenuator.
[0013]
In the speaker system of the present invention, when driving each speaker unit 7, 8 or 78 of the
speaker unit, the program memory of the DSP 6 for digital input signal processing shown in FIG.
Load the program of the FIR filter (Finite impulse response filter) or the filter program combining
the FIR and the IIR filter (Infinite impulse response filter), and also in the coefficient memory
(Coefficient response), the frequency possessed by each speaker unit itself Load a coefficient
(Coefficient) of inverse correction of the speaker response including distortion of the frequency
response (Frequency & Phase response).
[0014]
As shown in the block diagram of FIG. 4, the input signal 9 is subjected to arithmetic processing
of inverse correction of the frequency response and the phase response of the speaker body of
the present invention by the real time digital signal processing system by the DSP 6. A converter
10 converts a digital signal into an analog signal.
[0015]
In the present invention, the operation panel 12 of the DSP 6 forming the real-time digital signal
processing system is provided with an operation unit for changing the output volume of each of
the speaker units 7 and 8, and the analog attenuator 100 is Control is performed to determine
the volume of the playback sound, and numerical values indicating the set volume are user bits of
subcodes such as AES / EBU and SPDIF, which are serial transmission formats of digital audio
signals, Alternatively, of the subcodes, control data for volume control is incorporated into bits
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not required by the D / A converter 10 and is multiplexed into a signal for driving the speaker,
and the D / A converter is multiplexed. Transfer to the data block 10;
[0016]
With this configuration, the signal line 21 for volume control for the analog attenuator 14 shown
in the known example of FIG. 7 becomes unnecessary, so a defect due to contact failure of the
control line of the attenuator 14 or the like Because the DSP 6 signal processing and volume
control can be controlled by the same operation panel 12, the DSP 6 can be operated at an
optimal signal level, and the DSP 6's operation accuracy is always the best. Since the sound
volume can be set arbitrarily while being held in the state, the reduction of the S / N ratio and the
deterioration of the distortion factor do not occur in the reproduced sound.
In the D / A converter block 10, the volume information is taken out from the sub code, and the
level of the audio signal converted into analog by the D / A converter 10 is controlled by the
analog attenuator 100. The reason is that
[0017]
EXAMPLES Examples of the present invention will now be described.
FIG. 1 shows an example of a speaker body in the speaker system of the present invention, in
which a full hollow speaker unit 78 is mounted on the hollow EC by means of a rigid hollow 32sided frame EC. The speaker units 78 of this system are driven by a power amplifier 11.
The analog signal input to the power amplifier 11 is subjected to filtering processing in real time
by digital signal processing in the DSP 6 in order to correct the characteristics of the respective
speakers 78, and the digital output is subjected to D / A converter 10 A signal converted into an
analog signal is amplified by the power amplifier 11 to drive each speaker unit 78.
[0018]
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Second Example FIG. 2 is another example of the speaker body in the speaker system according
to the present invention, in which the hollow hollow sphere EC having a rigid hollow sphere is
provided with a speaker unit 78 of a full range, respectively. The speaker units 78 of this system
are also driven by the power amplifier 11 at an equal distance a from the center point 0 of the
sphere forming the EC. The signal input to the power amplifier 11 is processed in the same
manner as in the speaker system of FIG. 1, the input signal is a digital signal as it is, the analog
signal is A / D converted and the DSP 6 has speaker characteristics. Correction processing and D
/ A converted analog signal.
[0019]
FIG. 5 is another example of a speaker body in the speaker system according to the present
invention, in which a rigid hollow sphere enclosure EC is formed into 12 faces formed in a
pentagon on its outer surface. 1 and 20 faces 2 formed of hexagons are defined, and 12
loudspeaker units 7 for the bass range are fixed to all of the faces 1 set to the pentagons,
respectively. Another example of the speaker body in the speaker system according to the
present invention is formed by fixing twenty high-pitched speaker units 8 to each of all twenty
surfaces 2 set in . Even with the speaker body of the speaker system of the present invention in
which speaker units 7 and 8 for low and high range are arranged in a fixed relationship in a
hollow 32 face body, peak 4 and dip 5 in frequency response when driven as it is. Is substantially
the same as in the speaker body of the two embodiments. A real time digital signal processing
system mainly composed of the DSP 6 is inserted in front of the power amplifier 11 in order to
substantially flatten the above-mentioned peak 4 and dip 5 and the lowering of the low range.
[0020]
Therefore, in the present invention, to digitally process an analog or digital input signal, the
program memory of the DSP 6 is loaded with the program of the FIR filter or the combination of
the FIR and IIR filters, and the DSP 6 coefficient memory In this case, the coefficients of the
inverse correction of the frequency / phase response of the speaker including the distortion of
the frequency / phase response of each speaker unit 7, 8 itself are loaded.
[0021]
As a result, the input signal 9 is subjected to the arithmetic processing of the inverse correction
of the frequency response and the phase response of the speaker system of the present invention
by the real time digital signal processing system mainly composed of the DSP 6. The analog
signal is converted by the A converter block 10 and amplified by the power amplifier 11 to drive
the speaker system of the present invention.
03-05-2019
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[0022]
In the above embodiment, the correction of the peak 4 of the frequency response in the DSP 6 is
set to -8 decibels (dB) and the correction of the dip 5 is set to +10 decibels (dB).
Incidentally, this set value has a property of changing depending on factors such as the size
(volume) of the enclosure EC, the type of the speaker unit 7, 8 or 78 used.
In addition, the distance between the diaphragm of the speaker unit 7 for the door and the
distance between the diaphragm of the speaker unit for the tweeter are different from the center
0 of the hollow body 32. In consideration, the drive signal of the speaker unit 8 for the tweeter is
delayed by about 60 microseconds (.mu.sec) in this example as compared to the drive signal of
the speaker unit 7 for the weber. The analog signal input to the power amplifier 11 is subjected
to filtering processing in real time by digital signal processing in the DSP 6 for characteristic
correction of the respective speakers 7 and 8 as described above, and the digital output thereof
Is converted to an analog signal by a D / A converter.
[0023]
A hook such as a leg or a hook for installing or suspending each speaker body shown in FIGS. 1,
2 and 5 in the embodiment of the present invention is a speaker of the enclosure EC. It is
installed at an open place where no unit is provided, or a speaker unit is not provided at a
required place of the enclosure EC, and used there. Also, the introduction of the input cable to
each speaker unit in these cases may be performed in the same manner as described above.
[0024]
[Effects of the Invention] A speaker system for use in a professional speaker's hi-fi speaker
system, a loudspeaker such as a public address, or a point sound source for measuring the
acoustic characteristics of a hall, ie, electric The ideal form of a transducer that converts signals
into acoustic signals is required to have the ability to transfer substantially uniform vibrational
energy to the entire surrounding space, with the center of the spherical body or a polyhedron
03-05-2019
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close to a spherical body as the sound generation point. Conventionally, there has been a wide
directional speaker system such as a dodecahedron supplied as capable of exerting the abovementioned performance, but it has not been used so much for music reproduction. The reason is
that the number of radiating surfaces of the sound is small and it deviates largely from the above
ideal shape, and when a hollow polyhedron which is spherical or nearly spherical is used as a
speaker enclosure, such an enclosure specific frequency response That is, the correction process
of the so-called "fear" is not performed correctly and properly.
[0025]
According to the present invention, the structure of the speaker unit is mounted on 32 planes set
equidistant from the center of the enclosure of a hollow sphere or a polyhedron close to a sphere
such as a 32 sphere compared to the above-mentioned prior art. Thus, it is possible to radiate
and transmit uniform vibrational energy to substantially the entire space around the enclosure.
[0026]
Further, in the present invention, even in the case of a multi-way speaker system of two or more
ways in which dedicated speaker units are arranged for each specific sound range, the input
signal for each band is corrected by digital signal processing. The wave front of the sound
radiated from each speaker unit can be equivalently set approximately equidistantly from the
center of a polyhedron close to a spherical surface such as a spherical body or a 32-sided body.
Substantially uniform vibrational energy can be radiated to the entire space surrounding the
speaker system.
[0027]
Moreover, the speaker system of the present invention corrects the lowering of the low
frequency response of the digital signal processor (DSP) and suppresses the rise of the frequency
response which can be the frequency point at which the digital signal processing unit starts to
decrease. The possible dips are also corrected to bring about the effect of being able to cancel the
phase distortion due to the difference in distance from the center of the spherical body of each
speaker unit and the difference in response speed of the diaphragm of each speaker unit. .
[0028]
Furthermore, in the speaker system of the present invention, the structure of the enclosure to
which each speaker unit is attached has a spherical surface or a polyhedron shape close to a
spherical surface by a continuum of a curved surface or an L-shaped cross section. The
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accompanying noise due to the vibration of the box, which tends to occur in the system in which
the speaker unit is attached to the hexahedral enclosure, can be greatly suppressed.
Further, in the speaker system of the present invention, a plurality of high-range speaker units
are arranged around the speaker unit for middle and low frequency range where the sound easily
spreads, and this unit group is the entire outer surface of the spherical body or polyhedron. By
arranging in a well-balanced manner, the reproduced sound is likely to be diffused substantially
uniformly all around the enclosure in all bands, so the combination of the above-mentioned
performance realizes the emission of the point sound source / non-directional reproduced sound.
Greatly contribute to
[0029]
Since the present invention is as described above, it is possible to provide a point sound source /
nondirectional speaker system which is excellent in localization of sound image and excellent in
reproducibility of the spread feeling of the sound field. It is very useful as a high-fidelity speaker
system for public use, a loudspeaker for public broadcasting, etc., a point sound source for
measuring acoustic characteristics such as a hall, etc.
[0030]
Brief description of the drawings
[0031]
1 is a front view of an example of a speaker body in the speaker system of the present invention.
[0032]
2 is a cross-sectional view of another example of the speaker body in the speaker system of the
present invention.
[0033]
3 is a diagram showing an example of the peak and dip of the frequency response in the speaker
unit used in the speaker system of the present invention.
[0034]
4 is a block diagram of an example of the speaker system of the present invention.
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[0035]
5 is a perspective view showing an arrangement example of a speaker unit of another example of
the speaker body in the speaker system of the present invention.
[0036]
6 is a block diagram of an example of a planar baffle type speaker system using a digital
equalizer.
[0037]
7 is a block diagram of an example of a speaker system in which the speaker system of FIG. 6 is
arranged in parallel.
[0038]
Explanation of sign
[0039]
Reference Signs List 1 pentagonal surface 2 hexagonal surface EC enclosure 4 peak of frequency
response 5 dip of frequency response 6 DSP 7, 8 and 78 speaker unit 9 input signal 10 D / A
converter 11 power amplifier
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