JPH02239798

Patent Translate
Powered by EPO and Google
Notice
This translation is machine-generated. It cannot be guaranteed that it is intelligible, accurate,
complete, reliable or fit for specific purposes. Critical decisions, such as commercially relevant or
financial decisions, should not be based on machine-translation output.
DESCRIPTION JPH02239798
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
speaker array system in which a plurality of speaker units are arranged linearly, in a plane, or in
a three-dimensional manner, and the directivity is uniform from low to high To provide such a
speaker array system that can be controlled. (Conventional art) Conventionally, as this type of
system, as shown in FIG. Amplifier 15. A skier device comprising low-pass filters 21a, 2lb,..., 2na,
2nb, and speaker units 30, 31a, 31b,..., 3na, 311b alternately arranged linearly in the vertical
direction with different cutoff frequencies. It was known. As another example, as shown in FIG. 5,
the common signal source 12, delay devices 40, 41... 4n. There has been known a skier device in
which amplifiers 50, 51,... 5n and linear alternating speaker units 60, 61a, 6 lb,. (Problems to be
Solved by the Invention) However, in the case of the former sliding device, the total length of the
linearly arranged speaker units 30 to 3 nb is 2A, the wave diameter of the sound wave is λ, k is
k−2π / Assuming that λ, in the frequency band where kA <1.5, its directivity is only close to
omnidirectional. For example, in the case of 2A-1 meter, it becomes less than k-3 and the
frequency f becomes about 160 Hz, and in the lower frequency band, the desired directivity can
be obtained even if all speaker units 30 to 3nb are driven. I can not. Also, in the case of the latter
Sukika device, focusing on only a specific frequency band, the delay 調整 can be adjusted so that
the directivity approaches a desired one, but uniform directivity over a wide band Can not get.
That is, the directivity of the high range and the directivity of the low range are significantly
different in high and low range when the same delay is given using one delay device 40 to 4 n in
one system. It is practically difficult to control the directivity of a wide band across the high and
low ranges. In this device, in order to obtain sufficient directivity in the low frequency range, it is
necessary to increase the length of the speaker array, and the system becomes larger. The
directivity characteristics of the speaker units linearly arranged in this manner are extremely
different from the low range to the high range. In addition, typical filters used in the conventional
08-05-2019
1
method have too many restrictions on filter characteristics and can not be given free filter
characteristics.
Therefore, it is difficult to realize a return directivity control over a wide band. The invention
relates to the conventional rI! It was designed to solve one problem, and its objective is to use a
finite response length digital filter (Filo + t 1 nput Resonse Digital Filter, hereinafter abbreviated
as FIR filter). It is an object of the present invention to provide a directivity controlled speaker
array system in which uniform directivity can be easily obtained from the low tone range to the
high tone range. (Means for Achieving the II Problem) The gist of the present invention for
achieving the above object is to provide a plurality of loudspeaker units arranged in a straight
line, grouped in groups of at least one or more in one group, and this group The FIR filter is
composed of the same number of FIR filters corresponding to the number and a plurality of
amplifiers, and is branched from the common audio signal input terminal and passed through the
predetermined FIR filter, and then the FIR filter is amplified by the audio signal amplified by the
amplifier. The present invention resides in a directivity control speaker array system in which all
corresponding speaker units are driven. In addition to this, when the length of the speaker array
in which the speaker units are linearly arranged is 2A, the wavelength of the sound wave is λ,
and k is k−2π / λ, from the center to one end of the speaker array One or a plurality of
adjacent speaker units and the speaker units in the opposite direction symmetrical position
toward each other are grouped as one set and centered in the frequency range of 0.9 <kA × 1.8
The directivity controlled speaker array system is characterized in that the output sound
pressure of the speaker unit is controlled to be 3 dB or more smaller than the output sound
pressure of both of the speaker units at both ends. Furthermore, when the length of the speaker
array in which the speaker units are linearly arranged is 2A, the wavelength of the sound wave is
λ, and k is k−2π / λ, one or more from the center of the speaker array toward one end A
plurality of adjacent speaker units and the speaker units at symmetrical positions in the opposite
direction are grouped as one group, and the output sound pressure of the center speaker unit is
the speaker at both ends in the frequency range of 7 <kA <14. The directivity control speaker
array system is characterized in that control is performed by 3 dB or more larger than the output
sound pressure of either of the units. Furthermore, when the number of speaker units is an odd
number, only one central speaker unit is made into one set, and further, one or a plurality of
adjacent speaker units from the center to one end of the speaker array A directivity controlled
speaker array system is characterized in that the speaker units in opposite direction symmetrical
positions are grouped as one set.
(Operation) The above configuration is made using the FIR filter, so that the amplitude and phase
characteristics are arbitrarily set over a wide frequency range. Thereby, wide-band uniform
directivity control is realized. Also, in this way, not only in the high range but also in the low
range, the output sound pressure of the speaker units at both ends is particularly increased by 3
08-05-2019
2
dB or more compared to the central speaker unit. Thus, relatively sharp directivity characteristics
are easily obtained. (Embodiment) Next, an embodiment of the present invention will be
described in detail based on FIGS. 1 to 3. FIG. As shown in FIG. 1, the directivity control speaker
array system comprises a plurality of FIR filters 70 to 7}, a plurality of amplifiers 80 to 8n, and a
plurality of speaker units 90, 91a, 9 lb,. The audio signal generated by the 9 na 9 mb audio signal
source 14 is branched into plural and input to the FIR filters 70 to 7 n. The output signal of one
FIR filter 70-7n is input to one or more amplifiers 80-8n. The output signals of one amplifier 808n are input to one or more speaker units 90-9n. The speaker units 90 to 9 n are arranged
linearly, planarly or three-dimensionally. The FIR filters 70 to 7n have filter characteristics such
that the directivity of the system is closest to a desired one in accordance with the characteristics
of the amplifiers 80 to 8n and the speaker units 90 to 9n. In this case, in order to obtain uniform
directivity characteristics over a wide band, it is necessary to optimize and design the imaging
width and phase characteristics of the filters 70 to 7 n for each individual frequency point. In
general, as one of the features of the FIR filters 70 to 7n, since it is possible to freely give
pregnancy width / phase characteristics over a wide frequency range, it is most suitable and very
convenient for realizing the filter characteristics. It can be said. In other words, such filter
characteristics are difficult to realize without the FIR filters 70 to 7n in the present technical
level, and such filter characteristics are obtained from computer calculation by, for example, a
non-linear optimization method. A linear, planar or three-dimensional arrangement of a plurality
of speaker units 90-9n is hereinafter referred to as a speaker array. One or a plurality of adjacent
speaker units 90-9n and their symmetrical positions t-90-9n are grouped as one set, eg 91a and
9 lb, from the center to one end of the speaker array do.
When the number of speaker units 90 to 9n is an odd number, only one central speaker unit 90
may be set as one set. One FIR finder 70-7n controls all of the speaker units 90-9n in one set.
Speaker array front face O in a relatively low frequency range where 0.9 <k A <1.8, where the
length of the speaker array is 2 A, the wavelength of the sound wave is λ, and k is k − 2π / λ.
In order to reduce the sound pressure in the direction with a 90 ° angle to the direction of the
sound by 10 dB or more compared to the sound pressure in the front direction, either of the two
speaker units 9na and 9nb is used for the output of the central speaker unit 90 At least the
condition of 3 dB or more smaller than the output must be satisfied. An example of the directivity
characteristic obtained by the filter characteristic designed in consideration of the condition is
shown in FIG. In FIGS. 2 and 3, the thick solid line indicates the directivity characteristic when
the FIR filters 70 to 7 n are turned on, and the dotted line indicates that the FIR filters 70 to 7 n
are not in operation I? The directional characteristics at l (filter through) are shown. In addition,
sound pressure in the front direction of sound pressure in all directions from the front direction
of the speaker array to a direction having an angle of 30 degrees from the front direction of the
speaker array in a relatively high frequency range where 7 <kA <14. In order to make the
amount of reduction with respect to <15 dB, it is necessary to at least satisfy the condition that
the output of the central speaker unit 90 should be greater than the output of either of the two
08-05-2019
3
speaker units 9na and 9nb by 3 dB or more. An example of the directivity characteristic obtained
by the filter characteristic designed in consideration of the condition is shown in FIG. The present
invention can also be applied to microphone array systems having directivity for sound
collection. (Effects of the Invention) As described above, according to the present invention, the
FIR filter is used to optimize and control the amplitude and phase characteristics of the speaker
array for each frequency point, so that the bass range to the high range It is possible to easily
obtain uniform directivity over a wide band, and to obtain a remarkable effect that it becomes
possible to control the directivity in the low range, which was difficult in the conventional
method in particular.
[0002]
Brief description of the drawings
[0003]
FIG. 1 is a circuit block diagram of a directivity control type speaker array system according to
the present invention, FIG. 2 to FIG. 3 are directivity characteristics diagrams in the same
manner, and FIG. 4 to FIG. It is a circuit block diagram.
14: Signal source, 70 to 7 n: FIR filter, 80 to 8 n: Amplifier, 90-91 a-91 b to 9 na, 9 nb: Speaker
unit. 1, 2 and 3 kA = y. 2 kA = Q. Z
08-05-2019
4