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JP2018006963

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DESCRIPTION JP2018006963
Abstract: To provide a speaker device capable of reproducing a waveform of a sound signal of a
source in which a waveform of a sound including complicated harmonics is carved like a sound
of a stringed instrument more faithfully and reproduced. A surface of a vibrating body of a
speaker unit is used as a signal sound generation unit, and when a part other than the signal
sound generation unit is used as a noise generation unit, noise emitted from the noise generation
unit to the outside It is characterized in that the structure and the material of the noise
generating part are selected so that the amount is less than the allowable level. [Selected figure]
Figure 1
Speaker device
[0001]
The present invention relates to, for example, a speaker device capable of reproducing a
waveform of a sound signal of a source in which a waveform of a sound including a complicated
overtone is carved like a sound of a stringed instrument more faithfully and reproducing it.
[0002]
The audio HiFi device using the speaker device “When a sound signal normally cut in a normal
source such as a CD (sound recording medium) is reproduced by the speaker device, the
waveform of the reproduced sound is the original source. It should be said that this is a device
that faithfully reproduces the waveform of the sound carved in.
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The sound is identified by the waveform, so if the sound waveform of the source is reproduced,
the sound of the source is faithfully reproduced.
[0003]
However, it is easily imagined that conventional speaker devices would be difficult to faithfully
reproduce (waveform reproduction) without distortion and complex sound wave forms carved in
a common source. That is, there are "frequency characteristics" and "group delay characteristics"
as the characteristics of the speaker device, and theoretically, if these two characteristics are
good, good waveform reproduction can be performed. This is because it is a well-known fact that
the characteristics are far from ideal.
[0004]
Here, “frequency characteristics” are sound pressure characteristics of each frequency.
Further, when a signal of a certain frequency is input to a certain signal processing system, the
group delay (τg) is τg = dφ /, where the phase difference between the input waveform and the
output waveform is φ, and the angular frequency is ω. It is represented by dω. From the
viewpoint of signal transmission, it can be said that it represents the frequency dependency of
the time (delay time) taken from the input of a signal to the output thereof. That this is not ideal
(= not uniform) means that the delay time is different for each frequency.
[0005]
The group delay has a large value, particularly in the low-pitched portion of a large aperture
speaker, and thus, for a speaker with a diameter of 30 cm or less, for example, a 50 Hz sound
signal and a 500 Hz sound signal are simultaneously applied to the speaker However, from the
speaker, a sound of 50 Hz comes out several seconds after the sound of 500 Hz comes out first.
[0006]
If a sound signal having a waveform in which a 500 Hz wave is superimposed on a 50 Hz wave is
added to a speaker having such a group delay characteristic, the 500 Hz wave sound is
reproduced first, and then several milliseconds After some delay, the sound of the 50 Hz wave is
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reproduced, and the peak position of the 500 Hz wave above the 50 Hz wave moves by several
milliseconds.
That is, when a sound signal of a waveform in which a plurality of waves having different
frequencies are superimposed is added to such a speaker and reproduced, the waveform of the
sound coming out has a waveform in which the superimposed waveform is significantly
deformed. .
[0007]
Here, in particular, the waveform of a natural raw sound such as the sound of a stringed
instrument is different from the wave of the simple repetitive waveform, so to say, it should be
called a non-repetitive waveform or an asymmetric waveform, It is common for a complex shape
in which a number of waves different in wavelength (= frequency) are superimposed in a complex
manner. In the case of the sound of such a complex waveform, when there is a group delay, the
peak position (positional relationship in the time axis) of the wave of each wavelength changes. If
it does so, it will become a waveform different from the original waveform by itself. As a result, it
is clear that the sound itself to be reproduced will be different.
[0008]
In addition, if the frequency characteristics are not ideal, the peak height of the wave of each
wavelength can not be reproduced, and the waveform can not be reproduced even by itself. It is
expected that in the conventional speaker, both the "frequency characteristic" and the "group
delay characteristic" are far from ideal, so that the waveform reproducibility will necessarily be
considerably poor. In this regard, actually, for some sound sources, such as human singing voice
and string instrument sounds, the original sound waveform recorded on a CD etc. is compared
with the sound waveform when it is reproduced by the speaker When I tried it, it was confirmed
that the sound waveform when playing with the speaker was a waveform that was significantly
different from the original sound waveform.
[0009]
In recent years, digital filters such as FIR have been developed, and so-called sound field
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correction techniques using this digital filter have been developed (see Patent Document 1).
Among these sound field correction techniques, there are techniques for correcting "frequency
characteristics" and "group delay characteristics". Therefore, if it is possible to improve the
"frequency characteristics" and "group delay characteristics" and improve these characteristics
by the sound field correction device using this digital filter in the conventional speaker device,
"waveform reproducibility" is also It should be possible to improve.
[0010]
Japanese Patent Application Laid-Open No. 8-79879
[0011]
However, according to the research of the inventors of the present invention, even if the
correction of the "frequency characteristic" and the "group delay characteristic" is added to the
above-mentioned conventional speaker apparatus using the sound field correction apparatus
using a digital filter, It turned out that the improvement effect of "waveform reproducibility"
expected in theory can not be obtained sufficiently in practice.
[0012]
The present invention has been made to solve the above-mentioned problems, and it has been
found that “waveform reproducibility” is obtained when “frequency characteristics” and
“group delay characteristics” are corrected using a processing device including a digital filter.
A sufficient improvement effect can be obtained, whereby, for example, the waveform of the
sound signal of the source in which the waveform of the sound including complicated harmonics
is incised like the sound of a stringed instrument is reproduced as a sound more faithfully
reproduced Aims to provide a speaker device that can
[0013]
The means for solving the above problems are as follows.
(1) The amount of noise emitted to the outside from the noise generating unit when the surface
of the vibrating body of the speaker unit is a signal sound generating unit, and the other portions
excluding the signal sound generating unit are a noise generating unit The speaker device is
characterized in that the structure and the material of the noise generating unit are selected so as
to be equal to or less than the allowable level defined below.
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However, the allowable level does not perform the correction of the frequency characteristic and
the correction of the group delay characteristic when the correction of the frequency
characteristic and the correction of the group delay characteristic using the digital filter are
performed on the speaker device. In this case, it means the level at which the waveform
reproducibility will be significantly improved, and the waveform reproducibility means a test
sound having a waveform in which a plurality of waves having different frequencies
(wavelengths) are superimposed. Refers to the degree of coincidence of the two waveforms when
the waveform of the sound when reproduced by the speaker device as a sound source and the
waveform of the sound source is compared, and the time axis and sound pressure of both
waveforms in the range of a fixed time axis When the axes are aligned so that they can be
compared with each other so as to minimize the deviation between the two waveforms, the area S
of the area surrounded by the two waveforms formed in the part where the two waveforms
deviate is defined as the mismatch amount The amount of mismatch The smaller the value, the
higher the degree of agreement, and the higher the waveform reproducibility. Furthermore, with
the level at which the waveform reproducibility significantly improves, the amount of
inconsistency when correction is not performed is S1, and correction is performed. Let S2 be the
amount of non-matching in the case, and let the value of SK = (S1-S2) = (S1) × 100 (%) be the
repeatability improvement rate. Say.
(2) The test sound is a sound obtained by recording a natural sound such as a human voice or a
musical instrument, and the allowable level is a level at which the reproducibility improvement
rate SK exceeds 20%. It is a speaker apparatus given in (1) which makes it a feature. (3) The test
sound is a sound obtained by recording a natural sound such as a human voice or a musical
instrument, and the allowable level is a level at which the reproducibility improvement rate SK
exceeds 30%. It is a speaker apparatus given in (1) which makes it a feature. (4) Noise generated
by vibration of a unit structural member constituting the speaker unit, generated by vibration of
a mounting structural member to which the speaker unit is attached and other structural
members attached to the mounting structural member A sound absorbing member, a damping
member or a sound insulating member is disposed in a propagation path to the outside where
noise to be generated and noise emitted from the back surface of the vibrating body of the
speaker unit respectively reach the outside, and arrangement positions of these members The
speaker device according to any one of (1) to (3), wherein the amount of emitted noise to the
outside is selected to be equal to or less than the allowable level by selecting the structure or the
amount of arrangement. (5) A single-unit unit is configured to be able to reproduce the bass
region of the speaker device by combining a plurality of small-aperture unit speaker units with
insufficient ability to reproduce the bass region that the speaker device can reproduce. The
speaker device according to any one of (1) to (4), characterized in that (6) A speaker device
comprising: an amplification device portion for inputting necessary sound signals from a sound
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source and performing necessary processing and amplification; and a speaker device portion
connected to the amplification device portion, wherein the amplification device portion A
correction processing device is provided which performs processing for correcting group delay
characteristics and frequency characteristics of the speaker device, and the speaker device
according to any one of (1) to (5) is used as the speaker device portion. It is a speaker device
characterized by the above. (7) The speaker device according to (6), which is shipped after the
correction of the group delay characteristic and the correction of the frequency characteristic are
performed by the correction device after the manufacture of the speaker device and before the
shipment. is there. (8) The speaker device according to (6), wherein the correction is performed
in an anechoic chamber.
[0014]
According to the means of (1) to (8) described above, the case where the correction of the
“frequency characteristic” and the “group delay characteristic” is added to the speaker
device using the digital filter is compared with the case where the correction is not added. A
sufficient "waveform repeatability" improvement effect has come to be obtained.
[0015]
Such an action and effect is obtained due to the fact that it has not been recognized at all in the
prior art and is due to the following fact that the present inventor first elucidated.
a. The fact that the "waveform repeatability" improvement effect that can be theoretically
expected can not be obtained by applying the correction of the "frequency characteristic" and the
"group delay characteristic" by the digital filter to the conventional speaker device. b. The
reason is that in conventional speakers, correction of "frequency characteristics" and "group
delay characteristics" by digital filters is not effective. b1. In the conventional speaker device,
the "frequency characteristics" and "group delay characteristics" due to the digital filter are not
effective in the conventional speaker device because the front surface of the vibrating body of
the speaker unit, that is, the front surface of the cone paper If the sound to be emitted is a signal
sound and the sound emitted from other than the front surface of the cone paper is a noise, the
fact is that the noise is so large that the noise can not be ignored.
[0016]
Here, “noise emitted from other than the front surface of cone paper” means, for example,
sound emitted by vibration of a unit structural member constituting the speaker unit is emitted to
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the outside through some route. Noise generated, noise generated by the sound generated by the
vibration of the mounting structural member to which the speaker unit is attached and the other
structural member attached to the mounting structural member being emitted to the outside
through some path, And noise generated by the sound emitted from the rear surface of the
vibrator of the speaker unit toward the inside of the speaker box to the outside through various
paths.
[0017]
c.
According to the inventor's consideration, it was surmised that the reason why the correction is
not effective when the noise is large is because of the following reasons. c1. The correction
device simply measures the "frequency characteristics" and "group delay characteristics" of the
speaker device, and measures the "frequency characteristics" and "group delay" using a digital
processing device provided with a digital filter or the like. An inverse correction function having
exactly the same characteristics as the “characteristic” is created, and this digital processing
device is interposed between the source and the speaker device when the musical tone of the
source such as a CD is reproduced by the speaker device. The speaker apparatus is driven after
applying an inverse correction function to the signal from the source. By this, it is intended to
obtain flat "frequency characteristics" and "group delay characteristics". Specifically, the
measurement signal for measuring the "frequency characteristic" and the "group delay
characteristic" is reproduced by the speaker device, the sound is detected by the microphone,
and is input to the digital processing device provided with the digital filter and the like. The
"frequency characteristic" and the "group delay characteristic" of the speaker device are
measured to create a function (correction function) of the inverse correction thereof, and the
input sound signal is corrected using the correction function.
[0018]
c2. Here, this correction is a correction made to the "corn paper" of the speaker to the last (it
is the corn paper that vibrates and emits the sound, but it is the voice coil that vibrates the corn
paper) Because the sound signal is added to this voice coil, it is not a strictly accurate expression,
but here it is assumed that the voice coil vibration and cone paper vibration have a one-to-one
relationship. . That is, this correction measures the "frequency characteristics" and "group delay
characteristics" of the "cone" of the speaker vibrating depending on the sound signal applied to
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the last, and the function (correction function) of the correction thereof It is assumed that the
"frequency characteristics" and the "group delay characteristics" of the "corn paper" are
corrected.
[0019]
c3. In other words, when measuring "frequency characteristics" and "group delay
characteristics", the measurement signal is reproduced by the speaker device to emit
"measurement signal sound". This "measurement signal sound" is "cone". It is premised that the
paper is ejected only from "paper". c4. Then, it is premised that the inverse correction
function is created based on the measurement information ejected only from the “corn paper”,
and the correction is applied only to the “corn paper”. c5. However, if the "measurement
signal sound" for measuring the above "frequency characteristics" and "group delay
characteristics" includes sounds other than the measurement signal sound emitted from "corn
paper", that is, "noise". Assuming that the measured "frequency characteristics" and "group delay
characteristics" are not the "frequency characteristics" and "group delay characteristics" of "cone
paper", the noise and noise emitted from "cone paper" Become the “frequency characteristics”
and “group delay characteristics” of the synthesized sound. c6. As a result, correction is
performed on "corn paper" by an inverse correction function created based on the sound
obtained by combining the signal sound from this "corn paper" and the noise from other than
"corn paper". In particular, a correction error occurs due to the addition of the noise.
[0020]
c7. According to the inventor's consideration, even if correction is applied to the conventional
speaker device, the waveform reproducibility is hardly improved because, in the conventional
speaker device, “noise” generated from other than the above “corn paper” is extremely high.
Since there were many, it was presumed that the correction error became so large that the effect
of the correction could hardly be obtained. c8. That is, the conventional speaker is one in
which a speaker unit is attached to a speaker box made of a material as rigid as possible. Then, in
order to enable reproduction of a desired bass region, a so-called bass reflex system or a back
load horn system is used, or a closed box system in which a necessary volume is secured is used.
[0021]
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c9. In such a conventional speaker device, when a sound signal is added to the speaker unit
of the speaker device to vibrate the "cone", not only the "cone" vibrates, but the speaker unit is
configured. It is obvious that the unit structural member also vibrates as the cone paper vibrates.
c10. It is also apparent that when the unit structural member constituting the speaker unit
vibrates, the mounting structural member on which the speaker unit is mounted and the other
structural members mounted on the mounting structural member also vibrate. And since these
structural members are mechanically connected to the speaker box, they vibrate the speaker box.
As a result, a sound is generated from the surface of the speaker box. This sound is a kind of
noise other than the sound (signal sound) due to the vibration of the cone paper of the speaker.
In this regard, no matter how rigid the speaker box is made, it is not possible to prevent the
generation of sound only by varying the frequency components of the generated sound. This can
be seen immediately by bringing the music box unit into contact with a rigid material, but even if
it is a rigid material, it vibrates the material very easily to generate a loud sound.
[0022]
c11. Furthermore, the sound emitted from the back surface of the cone paper of the speaker
unit to the inside of the speaker box is reflected inside the speaker box, and a part of the sound
penetrates the cone paper and is emitted to the outside. This is a kind of noise because it is a
sound other than the sound due to the vibration of the cone paper. Also, when the noise
penetrates the cone paper, it vibrates the cone paper, which also generates a kind of noise other
than the signal sound from the cone paper. c12. In the case of the bass reflex type or the
back load horn type, in addition to the above noise, the sound emitted from the bass reflex port
or the back load horn is added to the speaker device. These sounds are also a kind of noise
because they are not sounds directly emitted from "corn paper" but sounds emitted with a
predetermined time delay from the sound emitted from "corn paper". c13. As described
above, it is considered that, in the conventional speaker device, various “noises” generated
from other than the above “corn paper” are summed up, resulting in extremely large noise.
[0023]
d. Therefore, the inventor of the present application made a trial experiment considering a
speaker having a structure in which "noise" from other than the above "corn paper" is not
generated as much as possible. d1. That is, first, the speaker unit is not attached to a rigid
speaker box, and the speaker unit is supported by a sound absorbing member that hardly
generates a sound even if vibration is transmitted. d2. Also, in order to absorb as much as
possible the sound emitted from the back side of the corn paper, the layer of the sound absorbing
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member as thick as possible is provided in the area on the back side of the corn paper.
[0024]
d3. In this way, an experimental machine was constructed in which the area on the back side
of the speaker unit is covered with the thickest possible sound absorbing member and, at the
same time, the sound absorbing member also supports the speaker unit itself. Specifically, a long
screw is fixed to a plurality of mounting holes provided in the circular frame of the speaker unit,
and a cylindrical area such as a wood or paper cross section is circular in a circular area
surrounded by these screws. One end of the open end of the cylindrical body is pressed against
the back of the circular frame of the speaker unit while the outer periphery of the body is
inscribed, and screws and the cylindrical body are fixed with vinyl tape etc. A sound insulating
wall was formed between the front and back sides of the cone paper. Then, the inside of the
cylinder is filled with the sound absorbing material, the layer of the sound absorbing material is
formed as thick as possible on the outside of the cylinder, and the surface of the circular frame of
the speaker unit is also covered with the sound absorbing material. In addition, in order to secure
a reproduction frequency band, if necessary, a plurality of small diameter units of 8 to 13 cm are
used for woofer and medium sound, and a tweeter is used to further provide a digital channel
divider and a plurality of amplifiers. It shall drive by the used multi-amplifier system.
[0025]
e. It is easily guessed that the above-mentioned experimental machine has a sufficiently small
occurrence of the above-mentioned "noise". The above-mentioned experiment machine was used
to measure the waveform reproducibility in the case where the above "frequency characteristics"
and "group delay characteristics" were not corrected and in the case where these corrections
were applied. As a result, it was found that the waveform reproducibility was significantly
improved as compared with the case where the correction was not applied, and it became
considerably similar to the original waveform. f. On the other hand, in the conventional
speaker device, it is not recognized that the waveform reproducibility is significantly improved as
compared to the case where the correction is applied but not the correction, and in any case, the
waveform is quite different from the original waveform. Met.
[0026]
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g. The results of the above experiments demonstrate that the effectiveness of the correction
depends on the presence or absence of noise. In other words, if noise can be removed effectively,
it indicates that the correction is effectively applied. Therefore, as long as noise can be removed,
it is of course possible to use a method different from that of the above-mentioned experimental
machine. For example, the speaker unit is attached to a rigid box (called a core box) as in the
prior art, and the core box is housed in a box slightly larger than the core box (called a shell box)
to block the vibration transmission between both boxes It may be something like this.
Furthermore, the surface of the box may be covered with a rubber member or the like. The point
is, of course, that any structure that effectively reduces noise may be used.
[0027]
The reproduction sound after "frequency correction" and "group delay correction" are applied to
the speaker device according to the present invention is a sound having a waveform that
reproduces the waveform of the sound of the source very faithfully, so to speak, the correct
reproduction It should be called a sound. As a result, the natural sound that seems to have many
harmonic components represented by the sound of a stringed instrument can be heard very
vividly and naturally, so to speak, it is also called a real sound that emits the brilliance of a bare
metal that has been completely stripped of plating. It sounds like it should. And that's not only
about specially chosen sources, but about many sources that seem to have been recorded
properly.
[0028]
In the case of a video, if color shift or distortion of the image is visible to anyone, it can be clearly
determined by anyone that it is not a correct video, but in the case of a sound, the sound can only
be heard. It is normal not to know at all whether the sound is correct or not. It seems that the
present condition is that even the definition of "correct sound" has not been decided in the first
place. In addition, there is a peculiar liveliness in the photographic image that directly captures
the site etc., and in the case of a photographic image, we can taste it normally in the case of a
photographic image, with little distortion of the recorded image. It is thought that it is because
the thing which can be done is natural. Similarly, in the case of sound, if it were possible to hear
the recorded sound waveform without deformation, it should be able to taste its unique
freshness. The reproduced sound obtained by reproducing the waveform of the source by
applying the “frequency correction” and the “group delay correction” to the speaker device
according to the present invention is also just to prove it.
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[0029]
Although the present invention is based on the discovery of a novel fact that “waveform
reproducibility” is improved by “noise removal”, in the present application, “the amount of
noise” is “waveform reproducibility. We do not adopt a method such as directly defining the
amount of noise itself by defining it as “amount below the level that will be significantly
improved”. This is because, at present, it is almost impossible to separate and measure only
"noise" from the sound emitted from the speaker device, so the amount of noise can not be
determined quantitatively. It is. In other words, no method has been found to properly identify
the present invention other than the indirect specific method as defined in the present
application. Although, for example, a method of specifying the structure of a speaker or the like
is also conceivable, since such a structure can be considered innumerably, it is impossible to
appropriately specify the present invention by a method of specifying such a structure. is there.
Furthermore, since the nature and degree of the generated noise vary depending on the
performance of the speaker unit, the material and structure of the box, etc., it is inappropriate
that the method of specifying only by the "reproducibility of waveform" is not appropriate. it is
obvious. From the above background, in the present application, it can not be concluded that the
invention can be appropriately specified only by introducing newly defined concepts of
"waveform reproducibility" and "waveform reproducibility improvement rate". It is According to
this specific method, “waveform reproducibility” is obtained even if “waveform
reproducibility” itself differs considerably depending on the performance of the speaker unit to
be used and the material and structure of the storage body such as a box for housing the unit. By
defining the rate of improvement, it is considered that the effect can be greatly reduced and the
essence of the present invention can be more appropriately specified.
[0030]
According to the above-mentioned means (5), as a speaker for reproducing the bass region, the
bass region can be reproduced by combining a plurality of small diameter unit speaker units
having an insufficient ability to reproduce the bass region by itself. As a result, it is possible to
reduce the group delay value of the bass region reproduction speaker and to reduce the
correction amount of the group delay. That is, since the group delay value of the speaker unit
increases as the aperture increases, the correction amount must be increased, but it is possible to
reduce the correction amount by using the small aperture speaker unit. Become. This makes it
possible to further improve the accuracy of the correction.
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[0031]
According to the above-described means (6) to (8), the user does not need to perform any
operation after the purchase, and simply by purchasing the speaker device, the "frequency
correction" and the "group delay correction" can be easily applied to the source It is possible to
enjoy the reproduced sound after reproducing the waveform of.
[0032]
Here, the group delay correction and the frequency correction by the sound field correction
device are performed using a digital filter such as a known FIR filter.
According to this, it is possible to relatively easily perform the correction without causing the
disturbance of the phase and the like. As these corrections are generally used in well-known AV
amplifiers and the like, a measurement signal for measuring group delay characteristics,
frequency characteristics, etc. is reproduced by an audio device, received by a microphone, and
analyzed. Then, based on the obtained group delay characteristics and frequency characteristics,
an acoustic transmission pressure function that performs inverse correction is created, and
correction is performed using that function. The correction device using the FIR filter can
perform more precise correction as the number of filter taps increases, so it is desirable to have
at least several thousand taps, and possibly several tens of thousands taps. In addition, it is
desirable that the processing frequency is also 192 kHz and 24 bits or more.
[0033]
It is a figure which shows the whole structure of the speaker apparatus 10 concerning Example 1
of this invention. FIG. 2 is a cross-sectional view showing a configuration of a bass speaker 11.
FIG. 1 shows an example of an audio system including a speaker device 10. The original sound
wave form carved in the sound source and the sound wave form in the case where the sound
signal of the original sound wave form is reproduced without the frequency correction and the
group delay correction by the conventional speaker device are superimposed and displayed FIG.
The original sound wave form inscribed in the sound source and the sound wave form in the case
where the sound signal of the original wave form is reproduced with the frequency correction
and the group delay correction performed by the conventional speaker device are superimposed
and displayed. It is a waveform comparison figure. The original sound wave form inscribed in the
sound source and the sound wave form in the case where the sound signal of the original sound
wave form is reproduced without the frequency correction and the group delay correction by the
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speaker device of Example 1 It is a waveform comparison figure displayed. The original sound
wave form inscribed in the sound source and the sound wave form in the case where the sound
signal of the original sound wave form is reproduced with the frequency correction and the
group delay correction performed by the speaker device of Example 1 It is a waveform
comparison figure displayed.
[0034]
First Embodiment FIG. 1 is a view showing the overall configuration of a speaker device 10
according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view
showing the configuration of a bass speaker 11. As shown in FIG. 1, the speaker device 10
according to the first embodiment includes four bass speakers 11, 12, 13, and 14 for playing a
bass region, and one for playing a middle and high tone region. And the coaxial type speaker 21
of FIG.
[0035]
As shown in FIG. 2, the bass speaker 11 includes an inner box 11a formed of a wooden plate or
the like having a thickness of about 1 to 3 cm and an outer box 11b for storing the inner box
11a. Have. The inner box 11a has a rectangular parallelepiped outer shape and is a box-like
body, and a speaker mounting hole 11d is formed in the front face 11c which is one end face in
the longitudinal direction, and the back face 11e which is the other end face is a closed face The
speaker terminal 11f is provided. The bass speaker unit 11g is attached to the attachment hole
11d. In this case, the bass speaker unit 11g is fixed to the inner box 11a using a fixing screw, nut,
etc. (not shown). The fixing screw, the bass speaker unit 11g, and the inner side A vibration
blocking member is interposed between the box 11a and the box 11a so that the vibration of the
bass speaker unit 11g is not transmitted to the inner box 11a. The size of the vertical cross
section of the inner box 11a is a size to which the bass speaker unit 11g is attached, and the
length in the longitudinal direction is several times or more of the diameter of the bass speaker
unit 11g.
[0036]
The outer box 11b is similar in shape to the inner box 11a, and its inner dimension is slightly
larger than the outer dimension of the inner box 11a, and between the outer wall 11h of the
07-05-2019
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inner box 11a and the inner wall 11i of the outer box 11b. The inner box 11a can be stored so
that a slight gap 11j is formed on the inner side. Then, a gel-like vibration blocking member 11k
is provided at an appropriate position in the gap 11i, and the inner box 11a housed in the outer
box 11b is supported. Further, the sound absorbing material 11m is appropriately filled in the
inner box 11a. In addition, since the other bass speakers 12, 13, 14 have the same configuration
as the bass speaker 11, the detailed description thereof will be omitted.
[0037]
The coaxial speaker 21 basically has the same configuration as that of the bass speaker 11
except that the coaxial speaker unit 21g is used instead of the bass speaker unit 11g, and thus
the detailed description thereof will be omitted. In addition, as a low-pitch speaker unit 11g, a
low-pitch speaker unit (woofer) having an aperture of about 10 to 13 cm can be used. In
addition, the coaxial speaker unit 21g has a middle sound portion 21g1 made of cone paper
similar to a normal speaker with a diameter of about 10 to 13 cm, and then a high sound portion
21g2 such as a tweeter is provided in the front center of the cone paper It is equipped.
[0038]
In addition, it is preferable to use as many as possible of a speaker with a small aperture as much
as possible for the bass speaker, but when using a commercially available speaker, one having a
size of about 1 inch to 6 inches is preferable. This is because, generally, the smaller the aperture
diameter, the better the group delay characteristic, so the amount of correction can be small and
the correction effect is considered to be more effective. Therefore, even if the aperture is large, it
is acceptable if there is a speaker with a small group delay, and if the performance of the
correction device is high, there is no particular concern with the aperture. Of course, the smaller
the aperture, the more speakers should be used.
[0039]
FIG. 3 is a diagram showing an example of an audio system including the speaker device 10. This
audio system includes a bass amplifier 51 for driving the bass speakers 11, 12, 13, and 14, a
mid-sound amplifier 52 for driving the mid-sound portion 21g1 of the coaxial speaker 21, and a
high-pitch drive for driving the treble portion 21g2. Amplifier 53, a digital channel divider 6 for
sending a bass signal, a middle tone signal and a high tone signal to these amplifiers, a
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preamplifier 7 with a sound field correction function for sending a sound signal to the digital
channel divider 6, and a sound field A sound source device 8 for sending a sound signal to the
pre-amplifier 7 with correction function. Note that two voice coils are connected in series to form
one pair, and two pairs connected in series are connected in parallel to form the bass amplifier
51 of the bass speaker units 11g, 12g, 13g, and 14g. Connected to the output.
[0040]
The bass amplifier 51, the midrange amplifier 52, and the treble amplifier 53 are amplifiers for
power amplification, respectively, and power amplification of the sound signal from the digital
channel divider 6 is performed for the bass speaker unit 11g to 14g, middle tone The speaker
21g1 and the high-tone speaker 21g2 are driven. It is desirable to use a full digital amplifier for
these amplifiers. This is because the digital amplifier is less likely to cause a group delay in the
amplifier. In addition, it is desirable that the path through which the sound signal passes be
digitally processed with as little group delay as possible. In that case, it is desirable that the
sampling frequency and the format of digital processing be as high as possible, such as 192 KHz
and 24 bits, for example.
[0041]
The digital channel divider 6 divides the sound signal sent from the pre-amplifier 7 with sound
field correction function into sound signals of bass, mid-tone and high-tone frequency regions
and respectively uses the bass amplifier 51, mid-tone amplifier 52 and treble amplifier It is sent
to the amplifier 53. The digital channel divider 6 is configured by using a large number of digital
filters such as FIR filters or IIR filters. This is because analog channel dividers using resistors,
capacitors, etc. are not preferable because they cause a group delay which is harmful to
waveform reproduction. A channel divider using a large number of digital filters such as FIR
filters or IIR filters can be configured by using a computer device programmed to operate as a
channel divider by operating a large number of digital filters such as FIR filters or IIR filters. If
possible, it is desirable to use an FIR filter with good phase characteristics. The number of taps of
the filter is several thousand or more, and if possible it is about one hundred thousand.
[0042]
The sound field correction function-equipped preamplifier 7 includes an amplifier for amplifying
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the sound signal sent from the sound source 8 and a computer device for executing the sound
field correction processing. Here, the sound field correction is a correction that performs all of
correction of group delay characteristics, correction of frequency characteristics, and correction
of room characteristics (mainly distortion correction due to a reflected sound of a room or the
like). Group delay correction, frequency correction, and room correction are performed using
digital filters such as well-known FIR filters. According to this, it is possible to relatively easily
perform the correction without causing the disturbance of the phase and the like. Also in this
case, the number of taps of the filter is several thousand or more, and several tens of thousands if
possible.
[0043]
As these corrections are generally used in well-known AV amplifiers and the like, an audio
apparatus reproduces a measurement signal for measuring group delay characteristics,
frequency characteristics and room characteristics, and receives them with a microphone. From
the obtained group delay characteristics and frequency characteristics, etc., to create an acoustic
transfer pressure function that performs inverse correction, and use that to make corrections,
and a computer programmed to perform those processing. This can be realized by incorporating
the device into the preamplifier 7 with sound field correction function. The sound source device
8 for transmitting sound signals reads out sound signals of a recording medium on which digital
or analog sound signals such as a known CD player or record player are recorded, converts the
sound signals into predetermined signals, and converts them into sound field correction
preamplifiers. It is a device to send to 7.
[0044]
Although not illustrated, the above-described speaker device 10, the bass amplifier 51, the
midrange amplifier 52, the treble amplifier 53, the digital channel divider 6, and the preamplifier
7 with a sound field correction function are provided in one case. It may be housed and
configured integrally, and may be configured as a so-called powered speaker with a built-in
sound field correction device.
[0045]
In that case, after production of the powered speaker device with a built-in sound field correction
device, the group delay characteristics may be corrected and the frequency characteristics may
be corrected by the sound field correction device before shipment.
07-05-2019
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The correction in that case is preferably performed in an anechoic chamber. According to this,
the user can immediately listen to the sound in a state where the correction is ideally performed
in the factory without purchasing the correction operation by himself. Of course, of course, it is
desirable to be able to perform room correction to take into account the acoustic characteristics
of the user's room after that.
[0046]
FIGS. 4 to 7 show a sound wave form in which a sound wave shape carved in a sound source and
a sound signal of the sound source reproduced by the above-described audio system using the
speaker device according to the first embodiment are detected by a microphone And the
waveform comparison figure which accumulated and displayed it. The solid line in the figure is
the sound wave form inscribed in the sound source, and the broken line in the figure is the sound
wave form detected by the microphone. In these figures, the time axis and the sound pressure
axis of the sound wave form inscribed in the sound source and the sound wave form detected by
the microphone are aligned so as to be comparable within a certain time axis range, and It
overlaps with the waveform and the detection waveform by the microphone so as to minimize
the difference. Then, the area S of the region surrounded by both waveforms formed in the
portion where both the waveforms are deviated is defined as the non-matching amount, and the
size of the area S is indicated by the alternate long and short dash line. That is, the area
surrounded by the base line of the chart and the dashed-dotted line is the mismatch amount S. In
these figures, as the waveform of the broken line is closer to the waveform of the solid line, the
area S which is the amount of mismatching becomes smaller, and the waveform reproducibility is
excellent. The sound wave form used is one in which a part of the female vocal is taken into the
waveform editing software, the time axis is expanded, and the time axis is made to coincide with
one another.
[0047]
4 shows the conventional speaker without sound field correction, FIG. 5 shows the conventional
speaker with sound field correction, FIG. 6 shows the speaker of Example 1 without sound field
correction, and FIG. 7 shows Example 1 Speakers with sound field correction. In addition, in the
above-mentioned waveform comparison, the sound field correction apparatus used the same
thing, and measured in the normal listening room. In addition, the measurement microphone was
placed about 100 cm from the speaker for measurement. In addition, as a conventional type
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speaker device, a commercially available high-grade speaker device of a 2-way bass reflex system
including a 16.5 cm aperture woofer and a 2.5 cm aperture tweeter and using a network was
used.
[0048]
From the results shown in FIGS. 4 to 7, in the conventional speaker device, it goes without saying
that there is no sound field correction, but the sound source waveform and the speaker
waveform are significantly different even in the case of the sound field correction. It is clear that
On the other hand, in the speaker apparatus of the first embodiment, the waveform of the sound
source and the waveform of the speaker are largely different in the case of no sound field
correction, but in the case of the sound field correction, the waveform of the sound source and
the waveform of the speaker It can be seen that the and clearly agree very well. That is, in the
conventional speaker, the sound field correction is hardly effective from the viewpoint of the
waveform reproduction, whereas it is understood that the sound field correction is very
effectively performed in the speaker device of the first embodiment. Here, the incoincidence
amount when the correction is not performed is S1, and the incoherence amount when the
correction is performed is S2, the value of SK = (S1-S2) / (S1) × 100 (%) is the reproducibility
improvement rate Define as
[0049]
Then, in the case of using the conventional speaker device, S1 = 88.7 and S2 = 81.6, and SK =
(S1-S2) × 100 = 8.0 (%). On the other hand, when the speaker device of the first embodiment is
used, S1 = 80.1 and S2 = 44.6, and SK = (S1-S2) ÷ (S1) × 100 (%) = 44. .3 (%). That is, the
improvement rate of waveform reproducibility by the above definition is 10% or less in the case
of the conventional speaker device, while it is 44.6% in the case of the speaker device of the first
embodiment, which is very high. there were.
[0050]
In addition, since the above-mentioned waveform measurement is a measurement in a normal
listening room, the influence of a reflected sound etc. can be considered and it can not always be
said that it is correct correction or measurement. However, when the above measurement results
are examined, it is presumed that sufficient information is obtained to confirm the effect of the
07-05-2019
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present invention even if there is a certain degree of error. Therefore, if measurement and
correction are performed in an anechoic chamber, it is easily guessed that better results can be
obtained. In addition, it may be considered that waveform reproducibility may differ depending
on the type of sound used for measurement, so it may not be sufficient to use many types of
sound. However, the sound used as the measurement sound source is a human singing voice with
musical instrument accompaniment which is one of the representative sounds frequently used as
a sound source, and various other complex waveforms having various wavelength components.
In addition to having a meaning as a representative example of the sound of and considering the
above-mentioned measurement results, it is inferred that sufficient information is obtained to
confirm the effects of the present invention even if there is a certain degree of error. Be done.
Furthermore, in the conventional speaker device, the improvement rate of waveform
reproducibility may be considerably different depending on the type of the device, and the
improvement rate of reproducibility of the conventional speaker device can not be uniformly in
what percentage. However, according to a survey of the inventors of the present invention, as a
result of examining the waveform reproducibility improvement rate for several models randomly
selected from the speaker devices having a good reputation for being very good quality, those
exceeding 10% It was not. Of course, this does not mean that the waveform reproducibility
improvement rate of all the conventional speaker devices is 10% or less, but it is possible to make
a tentative estimate. The waveform reproducibility improvement rate of Example 1 is much more
than 10%.
[0051]
If the improvement rate of waveform reproducibility exceeds 10%, most people can perceptively
recognize that the degree of agreement is improved even by waveform comparison with the
naked eye, and also in the sense of hearing, especially with regard to the sound of the strings, etc.
It has been confirmed that most people can recognize that the freshness is improved. In addition,
when the waveform reproducibility improvement rate exceeds 20%, the improvement in the
degree of waveform coincidence with the naked eye and the acuity in the sense of hearing
become clearer, and when it exceeds 30%, the degree of waveform coincidence with the naked
eye is more remarkable And it has been confirmed that the freshness on hearing is also
remarkably remarkable.
[0052]
According to the audio apparatus according to the above-described embodiment, the sound
signal waveform of the source in which the waveform of the sound including the complicated
07-05-2019
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harmonics is incised like the sound of the stringed instrument can be reproduced faithfully as the
sound signal waveform of the source. It is not possible for the first time to reproduce the sound
of That is, by correcting the group delay characteristic and the frequency characteristic, at least
the sound coming out of the speaker surface can be a faithful reproduction of the waveform of
the sound carved in the source. And by minimizing the sound coming from the surface of the
speaker and then correcting the room characteristics, it is possible to prevent the waveform of
the sound from coming out of the speaker surface from being deformed, so the waveform of the
sound carved in the source is It is possible to listen to the faithfully reproduced sound. This
means that by comparing the sound of the audio device according to the present embodiment
with the sound of various conventional audio devices, what is the original correct sound and how
the sound of the conventional audio device is deformed It is something that anyone can
immediately feel at a glance whether it is a sound that has been
[0053]
Furthermore, in the audio apparatus according to the present embodiment, it has been found that
the speaker unit in charge of the low-pitched part is constituted by a large number of small
diameter speakers, so that the speaker box can be formed extremely small compared to the prior
art. The That is, in order to reproduce the bass with the conventional large-aperture speaker, a
large box is essential. This is because a large space is required on the back side of the cone paper
in order to shake the entire area of one cone paper to produce bass.
[0054]
However, according to the present invention, it was found that the back space required for one
small-aperture speaker is very small, and it is sufficient for the total space to be very small
compared to the prior art. Therefore, although it is very small, it can produce a sufficient bass
and has a very fast response to vibrations, so the group delay is very small even in the bass, so it
is rather powerful. It has become possible to play. Furthermore, it turned out that the production
cost can also be very cheap. That is, small diameter speakers can be obtained at very low cost, so
using a large number of them can be sufficiently cheaper than one large diameter speaker, and
the speaker box can be made extremely small, and a particularly expensive material It has been
found that it can be configured at a sufficiently lower cost than conventional speaker devices,
since it is not necessary to use
[0055]
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11, 12, 13, 14 Bass Speakers 21 Mid-high range coaxial speaker 51 Bass amplifier 52 Mid-range
amplifier 53 High-tone amplifier 6 Digital channel divider 7 Pre-amplifier with sound field
correction function 8 sound source (sound source device)
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