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JP2008134421

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This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
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DESCRIPTION JP2008134421
The present invention provides a karaoke apparatus capable of imparting directivity to singing
voice while securing sound quality from low to high. A speaker array (5) includes high-sound
speaker units (51H to 58H), mid-sound speaker units (51M, 52M), low-sound speaker units (51L,
52L), and full-range speaker units (51F, 52F). The speaker units 51H to 58H are defined by the
inter-unit distance d4 = v / (2 * f4), the speaker units 51M and 52M are defined by d3 = v / (2 *
f3), and the speaker units 51L and 52L are d2 = v The speaker units 51F and 52F are defined by
d1 = v / (2 * f1). The singing voice is beam-controlled by the speaker units 51H to 58H, 51M,
52M, 51L, 52L, 51F and 52F and the other sounds are outputted from the speaker units 51F and
52F. [Selected figure] Figure 2
Karaoke device
[0001]
The present invention relates to a karaoke apparatus capable of controlling the directivity of
singing voices.
[0002]
Karaoke devices are installed in places where one room is occupied by a single group (such as a
karaoke box), and often installed in places where unspecified customers gather (e.g., restaurants
such as snack shops).
[0003]
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1
The conventional karaoke apparatus spreads accompaniment sound and singing voice in the
shop using a stereo speaker.
Therefore, when installed in a store where the above-mentioned unspecified customers gather, it
is possible for all the people in the store to hear the singing voice that anyone sings.
[0004]
In a restaurant such as a snack, the singing of another person (other group) is not necessarily
what you want to listen to, and in some cases it may be annoying.
However, in the above-mentioned conventional karaoke apparatus, since the singing voice of the
singing person is emitted to the whole store, there is a problem that all the customers have to
listen to the karaoke singing.
[0005]
Therefore, by using a speaker array, a device has been proposed in which directivity is given to
the sound emission so that only the group in which the singer is present can hear the singing
voice (for example, see Patent Document 1). JP 2005-173137 A
[0006]
In the device shown in Patent Document 1, when the width of the speaker array is increased, the
directivity characteristic is sharpened, and the sound beam can be concentrated in the target
direction. The beam width θ of the voice beam is determined by the following equation 1
(where, v is the speed of sound, d is the spacing between the speaker units, n is the number of
speaker units, and f is the frequency). θ = sin <−1> (v / fdn) (1) In order to sharpen the
directivity characteristics, ie, to increase the width of the speaker array, the number n of speaker
units is increased or the same number In order to carry out in, the interval d is increased.
However, if the distance d is increased, another voice beam (referred to as a side lobe) other than
the target direction is obtained due to the spatial aliasing phenomenon. Problems occur). In order
04-05-2019
2
to prevent side lobes, the distance d between the speaker units must be set so as to satisfy the
condition of Equation 2 below. d <v / 2f... In order to reduce the formula 2 d, it is necessary to
use a small diameter speaker unit. That is, the speaker units can not be overlapped and arranged,
and it is necessary to use a small diameter speaker unit in order to arrange the speaker units
close to each other. However, in the case of using a small-aperture speaker unit, there is a
problem that it is not possible to obtain sufficient sound quality (particularly, sound quality of
bass).
[0007]
An object of the present invention is to provide a karaoke apparatus capable of imparting
directivity to singing voice while securing sound quality from low to high.
[0008]
The karaoke apparatus according to the present invention arranges storage means for storing
song data for generating accompaniment sounds of karaoke songs, a microphone for inputting
singing voice, and a plurality of speaker units with different apertures, and a full range at the
array end A speaker array including a speaker unit for the speaker, a sound output processing
unit for delaying the singing voice and inputting directivity to each speaker unit, and inputting
the accompaniment sound to the speaker unit for the full range And control means for
controlling the sound output processing unit to output the song voice with directivity in a
specific direction, and the speaker array is the innermost array of the array Arranged in the highrange array section outside the high-range array section and the high-range array section in
which the speaker units having the same aperture are arranged at predetermined intervals from
the origin, and outside the high-range array section A mid-low range array section in which
speaker units having a larger aperture than the speaker unit arranged at a larger interval than
the high-range array section, the high-range array section and the mid-range array section In the
above, the intervals d of the respective speaker units are arranged at intervals given by the
following equation: d = v / 2f from the upper limit frequency f and the speed of sound v having
directivity.
[0009]
In this configuration, it has a speaker array in which speaker units having different diameters are
arranged.
At the end of the array, a speaker unit for full range (for example, having a sound output
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3
capability of 20 Hz to 20 kHz) is disposed.
Using this speaker array, the singing voice is output with directivity in a specific direction. Also,
the karaoke accompaniment sound is emitted from the speaker unit for full range at the end. The
sound quality from low to high is secured by using speaker units with different diameters. Near
the center of the array, speaker units of the same diameter are arranged at equal intervals, and
on the outside, speaker units with large diameters are arranged at wide intervals. The
arrangement interval of each speaker unit is defined by d = v / 2f using the upper limit frequency
f for giving directivity. In the high tone range array section (that is, the section in which the
upper limit frequency f is increased), speaker units with small apertures are arrayed at equal
intervals, and the interval d is reduced. In the mid-low range array section, the speaker unit
having a large aperture is set to have a larger interval d than the high-range array section. A
speaker unit having a large aperture may be disposed gradually toward the outside to widen the
arrangement interval, and the directivity of the bass may be secured as it goes to the outside. A
plurality of speakers with the same aperture may be arranged at equal intervals also in the
middle bass range arrangement section.
[0010]
In addition, the present invention is characterized by further comprising a filter for limiting the
band higher than the upper limit frequency f and inputting it to each speaker unit for the singing
voice.
[0011]
In this configuration, the band above the upper limit frequency f is cut, and the side lobe
generation above the frequency f is further suppressed.
[0012]
Further, the present invention is characterized by further comprising a phase compensation filter
for correcting the difference in phase characteristics among the plurality of speaker units with
respect to the sound input to each speaker unit.
[0013]
In this configuration, it is conceivable that the phase characteristics are different in the speaker
units having different apertures and phase interference may occur, but the speaker unit is
corrected with a filter that compensates for the phase difference between the speaker units for
singing voice and accompaniment voice. Enter in
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4
[0014]
Further, the present invention further comprises a microphone position detection unit for
detecting the position of the microphone, and the control means is configured to output the
singing voice with directivity in a direction including the position of the microphone. It controls
the sound emission processing unit.
[0015]
In this configuration, the position of the microphone is detected, and an audio beam is set to be
output in a direction including the position of the microphone.
It is sufficient for the singing voice to be emitted in the direction of the singer and its
surroundings (groups), so that the directivity may be limited to the direction including the
microphone position.
[0016]
According to this invention, it is possible to give directivity to singing voice while securing the
sound quality from low to high.
[0017]
A karaoke apparatus according to an embodiment of the present invention will be described with
reference to the drawings.
FIG. 1 is a block diagram of a karaoke apparatus, and FIG. 2 is an external view of a speaker array
used in the karaoke apparatus.
[0018]
The karaoke apparatus 1 includes a microphone 2A, a microphone 2B, a driver amplifier 3, an
audio signal processing unit 4, a speaker array 5, an ADC 6A, an ADC 6B, a microphone position
detection unit 7, a control unit 8, an accompaniment reproduction unit 9, and a storage unit 10.
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5
ing.
[0019]
The karaoke apparatus 1 receives a request for a karaoke song, reads the song data of the song,
performs a karaoke performance, and displays the lyrics of the karaoke song on a monitor (not
shown).
At the time of the karaoke performance, the accompaniment sound of the karaoke song (Karaoke
performance sound) is generated.
Also, play the guide vocal sound.
The karaoke performance sound and the guide vocal sound are amplified by the driver amplifier
3 and emitted from the speaker array 5.
[0020]
As shown in FIG. 2A, the speaker array 5 is configured by linearly arranging speaker units.
In FIG. 2, the right side in the drawing is the X direction, and the left side is the −X direction.
[0021]
The speaker array 5 includes speaker units 51H to 58H for high frequency range (for example, 4
kHz or more), speaker units 51M and 52M for medium frequency range (for example, 400 Hz to
4 kHz), and speaker units 51L and 52L for low frequency range (for example, 400 Hz or less)
And speaker units 51F and 52F for full range use (for example, 20 Hz to 20 kHz, which has a
higher sound output capability in the bass region than the speaker units 51L and 52L).
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In the example shown in the figure, eight high sound range speaker units, two mid range sound
speaker units, two low sound range speaker units, and two full range speaker units are arranged.
[0022]
The eight speaker units 51H to 58H are arranged at an inter-unit distance d4 in left-right
symmetry with the array origin which is the innermost of the array. The speaker units 51M
arranged outside (−X side) of the section where the eight speaker units 51H to 58H are
arranged are arranged at an inter-unit distance d3 with the speaker units 51H. Similarly, the
speaker units 52M arranged outside (X side) of the section in which the speaker units 51H to
58H are arranged are arranged at an inter-unit distance d3 with the speaker units 58H.
[0023]
Further, the speaker units 51L arranged on the outer side (−X side) of the speaker unit 51M are
arranged at an inter-unit distance d2 with the speaker unit 51M. Similarly, the speaker units 52L
arranged on the outer side (X side) of the speaker units 52M are arranged at a unit distance d2
with the speaker units 52M.
[0024]
Furthermore, the speaker units 51F disposed on the outer side (−X side) of the speaker units
51L are arranged at an inter-unit distance d1 with the speaker units 51L. Similarly, the speaker
units 52F disposed on the outer side (X side) of the speaker units 52L are arranged at a unit
distance d1 with the speaker units 52L. The relationship between the unit distances d1 to d4 will
be described in detail later.
[0025]
The number of arranged speaker units and the arrangement mode are not limited to this
example. For example, an arrangement as shown in FIG. 2 (B) may be used. In the example shown
in FIG. 2 (B), the high-tone speaker units 51H to 58H are linearly arranged in parallel in two
lines, the mid-range speaker units 51M and 52M are arranged on the outer side, and further on
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7
the outer side. The low-range speaker units 51L and 52L are arranged, and the full-range
speaker units 51F and 52F are arranged on the outermost side. By arranging in this manner, the
speaker array can be configured in a compact case. In the example shown in the figure, the
tweeter 51T and tweeter 52T that emit higher-pitched sound (for example, 10 kHz or more) than
the high-pitched speaker unit are arranged to improve the sound quality, but in the present
invention, the tweeter is used. Not required.
[0026]
By delaying and inputting an audio signal to each speaker unit of the speaker array 5 of this
configuration (for example, the configuration of FIG. 2A), an audio beam can be formed to have
sound emission directivity. . In addition, it is also possible to output with nondirectionality.
[0027]
Here, beam control will be described with reference to FIG. FIG. 3 is a diagram for explaining the
principle of forming an audio beam. The same figure (A) has shown the case where an audio
signal is simultaneously inputted into a plurality of speaker units SP arranged in a line. In this
case, sound is emitted simultaneously from each speaker unit SP. The sound waves output from
the individual speaker units SP propagate radially (circularly). Here, in the synthetic waveform of
the sound wave output from each speaker unit SP, the component propagating forward is
synthesized and strengthened. On the other hand, components propagating in directions other
than the front are canceled by interference of signal components output from the respective
speaker units SP. Therefore, only the forward component is enhanced by the synthesis into a
speech beam.
[0028]
The figure (B) is a figure shown about delay time control in the case of forming a voice beam
from a plurality of speaker units SP shown in the figure (A) diagonally. In this figure, the voice
beam is formed at an angle of θ from the front to the right. In this case, voice is first output from
the speaker unit SP at the end (left end in the same figure) opposite to the direction of the beam,
and after that time each time time τ elapses adjacently to the beam Audio is output to the
adjacent speaker unit SP. The inclination angle θ has a relationship of θ = sin <−1> (vτ / d),
where v is the velocity of sound. Therefore, it is possible to control the angle θ of the voice beam
04-05-2019
8
by controlling τ.
[0029]
Next, the control unit 8 includes a CPU, reads out song data of the karaoke song requested by the
singer from the storage unit 10 and inputs the data to the accompaniment playback unit 9.
Requests for karaoke songs are made using a remote controller (not shown) or the like. Further,
the control unit 8 reads beam control data (data defining the delay amount of the audio signal
input to each speaker unit) for controlling the audio beam of the speaker array from the storage
unit 10, and the audio signal processing unit 4 Control the
[0030]
The accompaniment reproduction unit 9 includes a guide vocal reproduction unit in addition to a
sound source for generating musical tones, and outputs a karaoke performance sound and a
guide vocal sound which is audio data. Guide vocal data is included in the song data of each
karaoke song. The karaoke performance sound and the guide vocal sound output from the
accompaniment reproduction unit 9 are input to the audio signal processing unit 4. The singing
voice signals input from the microphones 2A and 2B are converted to digital signals by the ADCs
6A and 6B and then input to the audio signal processing unit 4.
[0031]
The microphone position detection unit 7 detects the positions of the microphone 2A and the
microphone 2B. Although any position detection method may be used for the microphone 2A and
the microphone 2B, for example, the method shown in FIG. 4 is used. FIG. 4 is a conceptual view
showing microphone position measurement. The microphone position detection unit 7 receives
one end speaker unit 51F of the speaker array 5 and the other end speaker via the audio signal
processing unit 4 (the beam control unit 41A or the beam control unit 41B in FIG. 1). The same
inspection audio signal (for example, high frequency audio close to the audible limit) is
sequentially input to the unit 52F. The microphone position detection unit 7 detects the
collection timing when the inspection audio signal is collected from the microphone 2A
(microphone 2B).
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[0032]
The microphone position detection unit 7 counts time t1 from the timing at which the speaker
unit 51F outputs the measurement voice to the sound collection timing. In addition, the time t2
from the timing when the speaker unit 52F outputs the measurement voice to the sound
collection timing is measured. The microphone position detection unit 7 calculates the
microphone position using the time t1 and the time t2. That is, the microphone position detection
unit 7 can measure the distance between the speaker unit 51F and the microphone 2A and the
distance between the speaker unit 52F and the microphone 2A (microphone 2B) from the
relationship between the times t1 and t2 and the speed of sound. If the distance information
between the speaker unit 51F and the speaker unit 52F is included, the position of the
microphone 2A (microphone 2B) can be measured by triangulation. The position of the
microphone 2A (microphone 2B) is, as shown in FIG. 4, a distance r from the center position of
the speaker housing (as viewed from the top) and a front direction from the center position of
the housing It is expressed by a shift angle φ with respect to the axis (a direction orthogonal to
the long axis direction) (this is taken as an angle 0 degree).
[0033]
The microphone position detection unit 7 inputs information on the microphone position
detected as described above to the control unit 8. The control unit 8 reads beam control data for
controlling an audio beam of the speaker array 5 from the storage unit 10 based on the
information of the input microphone position, and controls the audio signal processing unit 4.
Details will be described later with reference to FIG.
[0034]
The singing voice signal input to the microphone 2A is digitized by the ADC 6A and then input to
the beam control unit 41A of the audio signal processing unit 4. The singing voice signal input to
the microphone 2B is digitized by the ADC 6B and then input to the beam control unit 41B of the
audio signal processing unit 4. On the other hand, the karaoke performance sound output from
the accompaniment reproducing unit 9 The guide vocal sound is input to the mixer 431 and the
mixer 432.
[0035]
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10
The beam control unit 41A controls the delay time for each speaker unit so that the singing voice
signal is output as a voice beam in the speaker array 5. Similarly, the beam control unit 41 B
controls the delay time of each speaker unit so that the singing voice signal is output as a voice
beam in the speaker array 5.
[0036]
The control unit 8 controls the beam output of the singing voice only in the direction in which
the singer and the group are present by setting separate beam control data to each of the beam
control units of the audio signal processing unit 4. Do.
[0037]
The audio signal (singing voice) whose directivity is controlled by the beam control unit 41 A is
input to the mixer 42, the mixer 431, and the mixer 432.
Similarly, the audio signal (singing voice) whose directivity is controlled by the beam control unit
41 B is input to the mixer 42, the mixer 431, and the mixer 432.
[0038]
In the mixer 42, the singing voice collected by the microphone 2A and the singing voice collected
by the microphone 2B are synthesized for each speaker unit. The synthesized singing voice is
converted into an analog voice signal by the DAC 45 H for each of the speaker units 51 H to 58
H of the speaker array 5 and is input to the driver amplifier 3. The driver amplifier 3 includes the
audio amplifiers 31H to 38H of the number corresponding to the speaker units 51H to 58H of
the speaker array 5, and amplifies the input audio signal of each speaker unit to obtain the
speaker array 5 (speaker unit 51H To 58H).
[0039]
In addition, the singing voice synthesized by the mixer 42 is converted into an analog voice
04-05-2019
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signal by the DAC 46 M corresponding to the speaker unit 51 M of the speaker array 5, input to
the audio amplifier 31 M of the driver amplifier 3, amplified and amplified. Output to the unit
51M). Similarly, the singing voice synthesized by the mixer 42 is converted into an analog voice
signal by the DAC 47 M corresponding to the speaker unit 52 M of the speaker array 5, input to
the audio amplifier 32 M of the driver amplifier 3, amplified and amplified. It is outputted to the
speaker unit 52M).
[0040]
In addition, the singing voice synthesized by the mixer 42 is converted into an analog voice
signal by the DAC 46L corresponding to the speaker unit 51L of the speaker array 5, input to the
audio amplifier 31L of the driver amplifier 3, and amplified to be the speaker array 5 (speaker
Output to the unit 51L). Similarly, the singing voice synthesized by the mixer 42 is converted into
an analog voice signal by the DAC 47 L corresponding to the speaker unit 52 L of the speaker
array 5, input to the audio amplifier 32 L of the driver amplifier 3, amplified and amplified. It is
outputted to the speaker unit 52L).
[0041]
The mixer 431 synthesizes a singing voice collected by the microphone 2A, a singing voice
collected by the microphone 2B, and a voice signal (Karaoke accompaniment sound, guide vocal
voice) generated by the accompaniment reproducing unit 9. The synthesized audio signal is
converted into an analog audio signal by the DAC 46F, input to the audio amplifier 31F of the
driver amplifier 3, amplified, and output to the speaker array 5 (speaker unit 51F).
[0042]
Similarly, in the mixer 432, the singing voice collected by the microphone 2A, the singing voice
collected by the microphone 2B, and the voice signal (Karaoke accompaniment sound, guide
vocal voice) generated by the accompaniment reproducing unit 9 are synthesized. The
synthesized audio signal is converted into an analog audio signal by the DAC 47F, input to the
audio amplifier 32F of the driver amplifier 3, amplified, and output to the speaker array 5
(speaker unit 52F).
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[0043]
By inputting an audio signal as described above, singing voice (microphone 2A, 2) can be
received from the speaker array 5 (speaker units 51H to 58H, speaker units 51M and 52M,
speaker units 51L and 52L, and speaker units 51F and 52F). The voice collected at 2B is output
as a voice beam. Further, the karaoke accompaniment sound and the guide vocal sound are not
beam-controlled, and are outputted from the full range speaker units 51F and 52F. Here, based
on the information on the microphone position input from the microphone position detection
unit 7, the control unit 8 sets the delay amount for each speaker unit so that the voice beam of
singing voice is directed to the microphone position (angle). Do. As a result, the singing voice is
beam output only in the direction in which the singer and the group are present.
[0044]
Beam control in an actual karaoke shop will be described with reference to FIG. In the figure, the
karaoke apparatus 1 is installed at the corner of the room 61 of the store. Four tables 71 to 74
are installed inside the room 61. This figure shows an audio beam formed when a customer on
table 71 sings a karaoke song. The karaoke accompaniment sound (and the guide vocal sound) is
emitted from the speaker array 5 to the entire room 61 in a nondirectional manner without beam
control (not shown). Further, in the direction of the table 71 of the singer, the singing voice is
emitted from the speaker array 5 by the voice beam 81.
[0045]
By emitting each audio signal in this manner, the accompaniment of the karaoke song can be
heard throughout the room 61, and the singing voice of the singer can be heard only at the table
71 of the singer. In the other tables 72 to 74, there is no need to listen to the singers of other
groups because the accompaniment sounds and guide vocals can be heard. When the singer
moves, for example, when singing is performed in the group of the table 72, the singing voice is
emitted from the speaker array 5 by the audio beam 82. The microphone position detection unit
7 periodically (or when instructed by the remote control) measures the position of the
microphone 2A (microphone 2B), and inputs information on the microphone position to the
control unit 8. Therefore, the singing voice is emitted in the direction (group) in which the singer
is present.
04-05-2019
13
[0046]
Next, the relationship between the distances d1 to d4 between the speaker units of the speaker
array 5 shown in FIG. 2 will be described. First, FIG. 6 is a diagram showing an example of the
sound beam control angle. The horizontal axis of the graph shown in the figure (A) represents θ
and the vertical axis represents the gain (G) of the speaker array. FIG. 11A shows the relationship
between the angle θ and the gain G in the case where the number n of speaker units n = 16, the
spacing d of the speaker units = 4.5 cm, and the width L of the speaker array = 67.5 cm, as an
example.
[0047]
In FIG. 6A, assuming that θ = 0 is the target voice beam direction, the gain G becomes maximum
at θ = 0. The sound output from each speaker unit interferes as the distance from θ = 0, and the
gain G decreases, and becomes zero at θ = ± θ1. The width until the gain G becomes zero
across the target voice beam direction θ = 0 is the beam width. Assuming that the gain G
becomes zero, that is, the width of the voice beam is f (1 kHz in the example of FIG. 6A),
according to the above equation, θ1 = sin <−1> (v / fdn) Is determined by That is, the beam
width θ1 is determined by the spacing d of the speaker units, the number n of the speaker units,
and the target frequency f.
[0048]
The figure (B) is the figure which showed the relationship of angle (theta) when the space |
interval d of a speaker unit is made into 4 time on condition of the figure (A), and the gain G. FIG.
Also in the graph shown in FIG. 6B, the horizontal axis represents θ, and the vertical axis
represents the gain. In the figure (B), the beam width has a sharp directivity in the target
direction than the beam width shown in the figure (A). Further, from the relationship of sin θ1 =
v / fdn, even if the target frequency f is quadrupled, a beam width as shown in FIG.
[0049]
FIG. 7C is a diagram showing the relationship between the angle θ and the gain G when f = 250
Hz, which is the frequency f being 1⁄4, under the condition of FIG. Also in the graph shown in
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14
FIG. 6C, the horizontal axis represents θ, and the vertical axis represents the gain. In the same
figure (C), θ1 where the gain G becomes zero does not exist, and no voice beam is generated. In
the condition of FIG. 6C, when the spacing d of the speaker units is quadrupled, a beam width as
shown in FIG. 6A can be obtained.
[0050]
The figure (D) is the figure which showed the relationship of angle (theta) when the space |
interval d of a speaker unit is made into 8 time on condition of the figure (A), and the gain G. FIG.
Also in the graph shown in FIG. 6D, the horizontal axis represents θ, and the vertical axis
represents the gain. In the figure (D), the sound beam (side lobe) is also generated in directions
other than θ = 0. This is a so-called space folding phenomenon, and when ddv / 2f, a
phenomenon as shown in FIG. Thus, the upper limit frequency which gives directivity (does not
cause a side lobe) is determined by the spacing d of the speaker units.
[0051]
In order not to cause side lobes at high frequencies, it is necessary to reduce the spacing d of the
speaker units, and conversely, it is necessary to increase the spacing d of the speaker units to
produce an audio beam at low frequencies. Therefore, the speaker array 5 of the present
embodiment arranges eight speaker units 51H to 58H for the high frequency range (the upper
limit frequency f = f4 giving directivity) at the inter-unit distance d4. Here, d4 is defined by the
target frequency f4 to d4 = v / (2 * f4). However, in the audio signals (singing voice) input to the
eight speaker units 51H to 58H, frequencies of f4 or higher are cut by the low pass filters (beam
control units 41A and 41B). The beam control unit 41A (beam control unit 41B) cuts frequencies
of f4 or higher for audio signals input to the speaker units 51H to 58H. As a result, the audio
beams output by the eight speaker units 51H to 58H do not generate side lobes at a frequency of
f4 or more.
[0052]
Loudspeaker units 51M and 52M for the midrange range (upper limit frequency f = f3 giving
directivity, where f3 is lower than f4) are arranged at an inter-unit distance d3 defined by d3 = v
/ (2 * f3) Do. Also here, the audio signal (singing voice) input to the speaker units 51M and 52M
is cut at a frequency of f3 or more by the beam control unit 41A (beam control unit 41B).
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Therefore, the sound beams output by the speaker units 51M and 52M (and the speaker units
51H to 58H inside the speaker units) do not generate a side lobe at a frequency of f3 or more.
[0053]
Similarly, the inter-unit distance specified by d2 = v / (2 * f2) for the speaker units 51L and 52L
for the low frequency band (the upper limit frequency f = f2 giving directivity, where f2 is a
frequency lower than f3) Arrange by d2. Also here, the audio signal (singing voice) input to the
speaker units 51L and 52L is cut at a frequency of f2 or more by the beam control unit 41A
(beam control unit 41B). Therefore, the sound beams output by the speaker units 51L and 52L
(and the speaker units inside the speaker units) do not generate a side lobe at a frequency of f2
or more.
[0054]
Furthermore, the inter-unit distance d1 defined by d1 = v / (2 * f1) for the speaker units 51F and
52F for full range (upper limit frequency f = f1 giving directivity, where f1 is a frequency lower
than f2) Arrange by Also here, the audio signal (singing audio) input to the speaker units 51F and
52F is cut at a frequency of f1 or more by the beam control unit 41A (beam control unit 41B).
Therefore, the sound beam output by the speaker units 51F and 52F (and the speaker unit inside
the speaker unit) does not generate a side lobe at a frequency of f1 or more.
[0055]
On the other hand, the accompaniment voice and the guide vocal voice are input to the full range
speaker units 51F and 52F without cutting the frequency components, and are emitted with
nondirectionality.
[0056]
As described above, the speaker array in which the speaker units having different apertures are
arranged defines the distance between the speaker units so that no side lobes occur in the
frequency band where beam control is performed while securing the sound quality from low to
high. Furthermore, by performing band limitation with a low pass filter, it becomes possible to
beam control singing voice.
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[0057]
Note that the audio signals input to the high sound range speaker units 51H to 58H may not be
low-pass filtered by the beam control unit 41A (beam control unit 41B).
By this, it is expected that the limitation of the high frequency band is eliminated and the sound
quality is further improved.
Although there is a possibility that side lobes will occur in the frequency band of f4 or more, the
voices emitted from the speaker units 51H to 58H are singing voices, and therefore the
frequency of f4 or more higher than the main band of human voice The sound emission level of
is small and can hardly be heard outside the intended direction.
[0058]
In FIG. 5, the directivity of the voice is not perfect, and there is a possibility that the singing voice
may be slightly leaked to the other tables 72 to 74, but the guide vocal voice singing the same
melody is in this place. Since the voice is emitted at a level higher than the leak level of the
singing voice by the voice beam, the masking effect makes the customer of this table hardly hear
the singing voice.
[0059]
The guide vocal sound may be input to a sound beam control unit (a beam control unit dedicated
to guide vocal sound) (not shown) other than the beam control units 41A and 41B in FIG.
Then, in the direction of the other tables 72 to 74, the guide vocal sound may be emitted from
the speaker array by the beams 82, 83, 84 of weak directivity. The accompaniment voice and the
guide vocal voice may be beam-outputted only in the direction in which the singer and the group
are present. In this case, the accompaniment voice is also input to a voice beam control unit (a
beam control unit dedicated to guide vocal voice) (not shown) other than the beam control units
41A and 41B.
[0060]
04-05-2019
17
Next, as described above, when speaker units having different diameters are disposed close to
each other, there is a possibility that the phase characteristic (frequency characteristic of phase)
between the speaker units may become a problem. That is, since the speaker units having
different apertures are disposed close to each other, there is a possibility that the emitted sound
of each speaker unit causes phase interference to affect the control of directivity. Therefore, as
described below, phase difference compensation filters (not shown) are provided at the
subsequent stages of mixer 42, mixer 431, and mixer 432, respectively, to compensate for the
difference in phase characteristics between the speaker units (referred to as phase difference).
Each audio signal may be corrected. The phase difference compensation filter is an FIR filter or
an all-pass filter realized by a second-order IIR filter, and corrects the phase characteristic of the
input audio signal. The filter coefficient of the phase difference compensation filter is set by the
control unit 8. The control unit 8 reads the setting parameter of the phase difference
compensation filter stored in the storage unit 10, and sets the filter coefficient based on this.
[0061]
FIG. 7 is a diagram showing the concept of phase difference and phase compensation. The figure
(A) is the figure which showed the phase characteristic of the speaker unit for bass, and the
phase characteristic of the speaker unit for middle sound. The horizontal axis of the graph shown
to the figure (A) represents a frequency, and a vertical axis | shaft represents a phase. The phase
characteristics shown in the figure are characteristics schematically represented to facilitate the
description, and do not represent the phase characteristics of an actual speaker unit.
[0062]
As shown to the figure (A), the phase with respect to the frequency f5 is set to ra1 in the speaker
for middle sound. On the other hand, the phase with respect to the frequency f5 in the low
frequency speaker is ra2. Therefore, the phase difference between the mid-range speaker and the
low-range speaker at frequency f5 is ra1-ra2.
[0063]
The figure (B) is the figure which showed the characteristic of the phase difference compensation
04-05-2019
18
filter. The horizontal axis of the graph shown to the figure (B) represents a frequency, and a
vertical axis | shaft represents a compensation phase. The characteristic of the compensation
phase is defined so as to make the phase difference shown in FIG. In this example, the
compensation is performed so that the phase difference becomes zero with reference to the midtone speaker, so that the compensation phase at the frequency f5 is ra1-ra2. A filter coefficient
having such a compensation phase is set in the phase difference compensation filter disposed in
the front stage of the bass speaker.
[0064]
As described above, FIG. 7 shows an example of the phase characteristic of the speaker unit and
is not an actual measurement result. In practice, the phase characteristic of each speaker unit of
the speaker array 5 is measured, the filter coefficient is calculated in advance so as to
compensate for the phase difference, and this is stored in the storage unit 10. The control unit 8
reads out the calculated filter coefficient and sets it as a phase difference compensation filter.
When an FIR filter is used as the phase difference compensation filter, the medium difference
speaker units 51M and 52M including the main band of human voice are used as a reference,
and the phase difference compensation filter corresponding to the other speaker units is used. It
should be compensated. The filter coefficients are obtained by inverse Fourier transform of the
phase difference. Since the delay occurs in the signal as the number of taps of the FIR filter
increases, the same delay is given to the phase difference compensation filter corresponding to
the reference speaker units 51M and 52M. The high-pitched speaker units 51H to 58H may be
used as a reference, or the low-pitched speaker units 51L and 52L may be set as a reference. Of
course, the speaker units 51F and 52F for full range may be used as a reference.
[0065]
When a second-order IIR filter is used as the phase difference compensation filter, filter
coefficients are defined as follows. FIG. 8 is a diagram showing the characteristics of the phase
difference compensation filter in the case of using a second-order IIR filter. The horizontal axis of
the graph shown in the figure represents frequency, and the vertical axis represents phase. The
figure (A) shows the phase characteristic of the speaker unit for middle sound and for the low
tone, the figure (B) shows the characteristic of a filter, and the figure (C) shows the speaker unit
after phase compensation. It shows phase characteristics. The characteristics shown in the figure
are also schematically represented for ease of explanation, and do not show the actual
characteristics of the speaker unit and the filter.
04-05-2019
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[0066]
As shown in the figure (A), the speaker unit for medium sound and the speaker unit for low
frequency have different phase characteristics. Therefore, a predetermined phase difference is
generated as shown in the graph shown at the bottom of the paper of FIG. The phase difference
is compensated by a filter (filter for medium sound) provided in the speaker unit for medium
sound and a filter (filter for bass) provided in the speaker unit for bass. As shown in the figure
(B), the filter for middle tone and the filter for low tone have the difference of the filter
characteristic which compensates the phase difference shown in the figure (A). Therefore, in the
speaker unit for medium sound and the speaker unit for low frequency, the phase difference is
reduced as shown in the graph at the bottom of the sheet of FIG. As described above, by
providing the second-order IIR filter at the front stage of each speaker unit (speaker array), an
all-pass filter that compensates for the phase difference can be realized. The characteristics
shown in the figure are not the actual measurement results. Of course, the filters actually used
are not limited to one as shown in FIG.
[0067]
Note that the frequency band for performing phase compensation may be limited. That is, phase
compensation is performed only in a band in which the sound emission capabilities of the
speaker units overlap. For example, if the sound output capability of the low-range speaker units
51L and 52L is 50 Hz to 450 Hz and the sound output capability of the mid-range speaker units
51M and 52M is 400 Hz to 4 kHz, then the sound output capabilities overlap 400 Hz to 450 Hz
Perform phase compensation only in the band of. In addition, when the speaker unit for full
range is used as a reference, phase compensation is performed on the band of the sound
emission capability of each speaker unit.
[0068]
Furthermore, in the present embodiment, the side lobes are further reduced by applying a
window function such that the volume of audio signals supplied to the respective speaker units
by the beam control units 41A and 41B decreases from the array center to the outside. Good. As
the window function, for example, a Hanning window or a Hamming window is used.
04-05-2019
20
[0069]
As described above, by installing the speaker array in which the speaker units having different
diameters are arranged, it is possible to provide the directivity of the singing voice while securing
the sound quality from the low tone to the high tone.
[0070]
In the present embodiment, the position of the microphone 2A (microphone 2B) is measured by
the microphone position detection unit 7 and beam control is performed according to the
detected microphone position. However, in the present invention, microphone position detection
and microphone The configuration for performing beam control according to position is not
essential.
[0071]
It is a block diagram which shows the structure of a karaoke apparatus.
It is an external view of a speaker array.
It is a figure for demonstrating the formation principle of an audio | voice beam. It is a
conceptual diagram which shows a microphone position measurement. It is a figure explaining
beam control in the actual karaoke shop. It is the figure which showed the example of the audio |
voice beam control angle. It is the figure which showed the concept of phase difference and
phase compensation. It is the figure which showed the characteristic of the phase difference
compensation filter at the time of using a 2nd-order IIR filter.
Explanation of sign
[0072]
1-Karaoke device 2A, 2B-microphone 3-driver amplifier 4-voice signal processing unit 5-speaker
array 6A, 6B-ADC 7-microphone position detection unit 8-control unit 9-accompaniment
reproduction unit 10-storage unit
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