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DESCRIPTION JP2007158636

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DESCRIPTION JP2007158636
A loudspeaker having a plurality of transducers of at least two different dimensions, the
transducers being arranged symmetrically about a first axis and a second axis perpendicular to
the first axis. A loudspeaker is provided which comprises a transducer whose center is located
along the loudspeaker at a position which is not on either the first axis or the second axis. A
loudspeaker has a plurality of transducers of at least two different dimensions, the plurality of
transducers being symmetrical with respect to a first axis and with respect to a second axis
perpendicular to the first axis. And the loudspeaker includes a transducer whose center is located
along the loudspeaker at a position not on either the first axis or the second axis. [Selected
figure] Figure 1
ラウドスピーカのアレイシステム
[0001]
TECHNICAL FIELD The present invention relates generally to multi-way loudspeaker systems. In
particular, it consists of loudspeaker drivers arranged symmetrically in a two-dimensional plane
to achieve high quality sound in combination with stereo loudspeaker systems, multi-channel
home entertainment systems and public information broadcast systems The invention relates to a
multi-way loudspeaker system.
[0002]
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1
Loudspeaker designers have a wide range of frequency bands despite limitations on the size and
number of transducers (eg drivers) as well as on the number of required amplifiers (eg ways) in
the system There is a constant effort to design a controlled directional loudspeaker system to
achieve high quality sound over. Achieving such high quality sound over a wide frequency range
may change the dimensions of the transducer for the dedicated parts of the audio frequency
band and the constraints on the spacing between the transducers. To be a difficult task.
[0003]
High quality loudspeakers for the audio frequency range generally employ multiple drivers
dedicated to each part of the audio frequency band, which are tweeters (generally 2 kHz to 20
kHz), mid-range drivers (generally 200 Hz to 5 kHz) And woofers (generally 20 Hz to 1 kHz).
Generally, higher frequency drivers are smaller in size than lower frequency drivers.
[0004]
In order to achieve high sound quality, it is desirable to place the drivers as close together as
possible in the loudspeaker. However, due to the physical dimensions of the dedicated drivers,
the possibility of placing the drivers close to one another is limited. The more distant the drivers
are from one another, the more acoustic problems arise.
[0005]
The acoustic output of the driver is usually in the loudspeaker called the acoustic center, as the
spacing is comparable to the wavelength of the sound to be emitted, due to the spacing between
the drivers due to their physical dimensions. Combined on only one vertical line, a flat response
independent of the intended frequency is obtained. At that off-axis point, the frequency response
will be more or less distorted due to interference due to different acoustic wave arrival path
lengths from each driver to space considerations. Thus, many attempts have historically been
made to construct loudspeakers with controlled sound fields so that a smooth response can be
obtained in large spaces, even at off-axis locations.
[0006]
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Current technology for controlling the sound space in large spaces, such as public spaces, is to
use a horn to enhance the evenly distributed sound. However, the use of uniformly arranged
horns has drawbacks. Uniformly arranged horns have a limited frequency range, a fixed nonredirectable polar pattern, and relatively high distortion.
[0007]
Current two-dimensional arrays for surround sound in home entertainment, so-called sound
projectors, are arrays of the same small, wide band driver linearly spaced. An array of this type
can produce multiple sound beams, which radiate into the room and produce the desired sound
effect during the bounce from the wall to the listener. However, although the drivers of the twodimensional, linearly spaced array are identical and the maximum sound pressure and sound
quality of the sound projector is limited by the performance of the transducer, it is generally
proprietary. It is inferior to the drive unit optimized for the frequency band of Furthermore, the
sound projectors use a very large number of drivers which all have to be driven individually,
which leads to a great deal of complexity and high cost of implementation.
[0008]
Thus, using a minimal number of converters as well as amplifiers, the converters are optimized
for high performance by using dedicated drivers across the audio frequency band such as
tweeters, midrange drivers or woofers There is still a need for a low-distortion, two-dimensional
loudspeaker configuration of quality. There is still a further need for a two-dimensional
loudspeaker configuration, which electronically changes the beam width and direction angles on
site, unlike fixed devices that use an array of horns.
[0009]
SUMMARY OF THE INVENTION (Item 1) A loudspeaker having a plurality of transducers of at
least two different dimensions, the plurality of transducers being parallel to the first axis and
perpendicular to the first axis Arranged symmetrically with respect to two axes, the loudspeakers
along the loudspeaker at a position not on either the first axis or the second axis. Loudspeaker,
including the transducer where the is placed.
[0010]
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(Item 2) The transducer of the loudspeaker, arranged symmetrically with respect to both the first
and second axes, filters the digital output signal filtered through at least one digital FIR filter, The
loudspeaker according to item 1, received from at least one power D / A converter.
[0011]
3. The loudspeaker according to claim 1, wherein the plurality of transducers of the at least two
different dimensions are a tweeter and a midrange driver.
[0012]
4. The loudspeaker according to claim 1, wherein the plurality of transducers of the at least two
different dimensions are a tweeter and a woofer.
[0013]
5. The loudspeaker of claim 1 wherein the plurality of transducers of the at least two different
dimensions are mid-range drivers and tweeters.
[0014]
6. The loudspeaker according to claim 1, wherein the plurality of drivers include a tweeter, a
midrange driver and a woofer.
[0015]
7. The loudspeaker according to claim 1, wherein one of the plurality of transducers is centered
at the intersection of the first and second axes.
[0016]
8. The loudspeaker according to claim 7, wherein the central converter receives a digital output
signal filtered via at least one digital FIR filter from at least one power D / A converter.
[0017]
(Item 9) The linear phase filter coefficients for each FIR filter determine the initial driver position,
determine the initial directivity objective function for the system, and the cost minimum based on
the initial directivity objective function. 3. A loudspeaker according to claim 2, determined by
applying an equalization function and calculating linear phase filter coefficients for each filter of
the system.
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[0018]
10. The loudspeaker according to claim 9, wherein the initial driver position is a coordinate
associated with an origin which is the center of the loudspeaker.
[0019]
11. The loudspeaker according to claim 9, wherein frequency points are determined on a
logarithmic scale of a predetermined frequency range based on the determined initial directivity
objective function.
[0020]
12. The loudspeaker according to claim 9, wherein the cost minimization starts at the lowest
frequency and increases in steps and is a function applied at the frequency points.
[0021]
13. The loudspeaker according to claim 9, wherein a Fourier approximation is used to establish
the linear phase filter coefficients.
[0022]
(Item 14) The directivity of the loudspeaker array along an axis perpendicular to the direction in
which the array is arranged while maintaining the directivity of the array along the axis in which
the array is arranged A method for altering at least one transducer centered on the axis on which
the linear array is arranged, and centered on the axis on which the array is arranged. Comprising
replacing by at least one set of pairs of transducers substantially identical to the transducers
having a pair of the transducers in which one of the transducers is arranged in the array upon
replacement. The other transducer of the pair is disposed on one side of the axis and the same
distance from the axis on which the array is disposed on the opposite side of the axis on which
the array is disposed, the opposing pair being The axis on which the array is arranged So as to be
arranged at the same distance from said axis perpendicular direction against, replaced, method.
[0023]
15. The loudspeaker of claim 14, wherein the pair of converters receives a digital output signal
filtered via at least one digital FIR filter from at least one power D / A converter.
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[0024]
(Item 16) The directivity of the loudspeaker array along an axis perpendicular to the direction in
which the array is arranged while maintaining the directivity of the array along the axis in which
the array is arranged A method for altering the at least one transducer centered on the axis on
which the linear array is arranged, the transducer being substantially identical to the transducer.
Comprising replacing by at least one pair of pairs, the transducers of the pair being arranged in
mirror images of one another with respect to the axis, at a point along the axis at which the array
is arranged The method wherein the directivity of the axis on which the array is arranged is
maintained.
[0025]
17. A loudspeaker system comprising at least five transducers of at least two different
dimensions, the at least five transducers comprising a first axis and a first axis perpendicular to
the first axis. At least one pair of substantially identical transducers, arranged symmetrically
about both of the two axes, having their centers parallel to one another with respect to the first
axis, one of the pairs A transducer is placed on one side of the second axis and the other
transducers in the pair are on the opposite side of the second axis, the same distance from the
axis as the other transducers in the pair Loudspeaker system, which is placed to be.
[0026]
SUMMARY The present invention is a multi-way array loudspeaker that can produce high quality
sound in high fidelity stereo systems, multi-channel home entertainment systems or public
information broadcast systems.
[0027]
In one embodiment, the array includes a plurality of tweeters, midrange drivers and woofers
disposed in a single housing or assembled into a single unit, the housing or unit being a coupling
of the drivers Have enclosed compartments that separate several drivers from each other.
The array may be single channel, with various signal paths from the input to individual
loudspeaker drivers or to multiple drivers.
Each signal path comprises a digital input and includes a digital FIR filter, a D / A converter and a
power amplifier connected with a single driver or multiple drivers, or a so-called power D / A
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converter.
[0028]
The performance, position and placement of the loudspeakers in the array may be determined by
a filter design algorithm that determines the coefficients for each FIR filter in the flow path of
each signal of the loudspeakers.
A cost minimization function is applied to a given frequency point using the initial driver position
and the initial directivity objective function defined at frequency points on a logarithmic scale
within the frequency range of interest.
If the result obtained by the application of the cost minimization function does not meet the
performance requirements of the system, then the location of the driver can be corrected and the
cost minimization function is rerun until the obtained result meets the system requirements. It
may apply.
When the results obtained match the requirements of the system, the filter coefficients for each
of the linear phase FIR filters in one path are calculated using Fourier approximation or other
frequency sampling method.
[0029]
The multi-way loudspeakers of the present invention may include built-in DSP processing, D / A
converters and amplifiers, and may be connected with digital networks (e.g. IEEE 1394 standard).
Furthermore, the multi-way loudspeaker system of the present invention may also be designed as
a wall mountable surround system because of its affordable size.
[0030]
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Multi-way loudspeaker systems can adopt drivers with different dimensions, less distortion
generated, high power handling, because a dedicated driver differs from an array of wide-band
identical drivers, its own proprietary It is because it can operate optimally in the frequency band.
The multi-way speaker design of the present invention also provides better control of the
response in the room to have a smooth response at the out-of-axis position.
The system can also control the frequency response of the reflected sound as well as the total
sound power and suppress floor and ceiling reflections.
[0031]
Other systems, methods, features and advantages of the present invention will be or become
apparent to one with skill in the art upon examination of the following drawings and detailed
description.
It is intended that all these additional systems, methods, features and advantages be included
within this description, be within the scope of the present invention, and be protected by the
accompanying claims.
[0032]
The invention can be better understood with reference to the following drawings.
The components in the drawings are not necessarily to scale, emphasis instead being placed
upon illustrating the principles of the invention.
Further, the same reference numerals in the drawings designate corresponding parts in different
drawings.
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[0033]
FIG. 1 shows an embodiment of a one-dimensional (1D) multi-way loudspeaker 100 on which the
present invention is based, and a block diagram of the signal flow to each loudspeaker driver of
the system 100.
As shown in FIG. 1, the multi-way loudspeaker 100 is connected to (1) the central tweeter 102
connected to the first power D / A converter 103, and (2) to the second power D / A converter
105. Two additional tweeters 104 and 106, (3) two mid-range drivers 108 and 110 connected
with the third power D / A converter 107, and (5) a fourth D / A converter 109. , And can be
designed as a four way loudspeaker with two woofers 112 and 114 connected thereto.
The connection between each loudspeaker and the amplifier represents a different way in the
multi-way loudspeaker.
[0034]
In FIG. 1, the driver, also referred to as a transducer, may be mounted in a housing 116
consisting of compartments 120, 122 and 124 separated and sealed by separators 132 and 134
as shown.
By mounting the drivers in a separate and sealed compartment, coupling between adjacent
drivers is minimized.
Although various compartments can be seen in FIG. 1, the loudspeaker system may be designed
such that the compartments are invisible to the consumer when embodied as a finished product.
The compartment 124 containing the woofer 112 can be separated by a separator 132 from the
compartment 120 containing the midrange drivers 108 and 110 and the tweeters 102, 104 and
106.
Similarly, the compartment 122 containing the woofer 114 may be separated by a separator 134
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from the compartment 120 containing the midrange drivers 108 and 110 and the tweeters 102,
104 and 106.
All the tweeters 102, 104, 106 may be included in the same compartment 120 as the midrange
drivers 108 and 110, because the tweeters 102, 104 and 106 are generally sealed, and the
tweeters 102, 104 and 106 from the midrange drivers It is because there is no need to separate.
[0035]
FIG. 1 shows center tweeter 102, tweeters 104 and 106, midrange drivers 108, 110 and low
frequency woofers 112 and 114, which are linearly along the y-axis and symmetrical about
center tweeter 102. It has been incorporated. Typical arrangements include tweeters 102, 104
and 106 of about 40 mm to 50 mm outer diameter, midrange drivers 108 and 110 of about 80
mm to 110 mm outer diameter, and woofers 112 and 114 of about 120 mm to 250 mm outer
diameter. May be included. In general, the dimensions of the transducer cones may vary based on
the desired use and the desired array dimensions. Furthermore, although the transducer may use
a neodymium magnet, using that particular type of magnet is not necessary for the described
application.
[0036]
When using a 50 mm diameter tweeter, a 110 mm mid-range driver and a 160 mm woofer, an
example of the system is a center tweeter built into center point 0, which is the intersection of
the x and y axes on the y axis. 102 may be included. The tweeters 104 and 106 may be
incorporated at their centers about +/− 60 mm from the center point. The midrange drivers 110
and 108 may then be incorporated at their centers from a center point 0 to about +/- 150 mm.
The low frequency woofer 112 and 114 may then be incorporated at its center about +/− 300
mm from the center point.
[0037]
FIG. 1 also shows a block diagram 140 of the signal flow of the multi-way loudspeaker system.
Although FIG. 1 shows four ways of signal streams 142, 144, 146 and 148, the channel may be
divided into two or more ways. The signal flow comprises digital inputs 150 which may be
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implemented using standard connection formats such as SPDIF or IEEE 1394 and their
derivatives, via various paths or ways as shown in FIG. Can be connected to the driver. Each path
or way 142, 144, 146 and 148 includes a power D / A converter 103, 105, 107 and 109
connected to a digital FIR filter 152 and one or more loudspeaker drivers respectively obtain.
Power D / A converters 103, 105, 107 and 109 are class D power amplifiers with cascades of
conventional audio D / A converters (not shown) and power amplifiers (not shown) or with direct
digital inputs It can be realized by (not shown). FIR filter 152 may be implemented by a digital
signal processor (DSP) (not shown). The loudspeaker driver may be a tweeter, a midrange driver
or a woofer as shown.
[0038]
In operation, the outputs of each of the plurality of FIR filters 152 are connected to the plurality
of power D / A converters 103, 105, 107 and 109 and then the plurality of loudspeakers
attached to the baffle of the housing 116. It is supplied to the drivers 102, 104, 106, 108, 110,
112 and 114. More than one driver, such as 104 and 106, may be connected in parallel to the
paths or ways 142, 144, 146 and 148 including the power D / A converters 103, 105, 107 and
109.
[0039]
FIG. 2 shows a two-dimensional multi-way loudspeaker 200 obtained by separating the tweeters
104 and 106 and the midrange drivers 108 and 110 of FIG. 1 into pairs. As further described
below, the paired drivers may be electrically coupled to one another and may be provided by the
same filter as the one-dimensional (1D) multi-way loudspeaker 100 of FIG. Thus, the directivity
along the y-axis is not affected and in far-field space the same directivity as originally defined is
maintained. However, new pointing characteristics can be introduced along the x-axis as desired.
[0040]
In particular, FIG. 2 shows a one-channel two-dimensional four-way loudspeaker 200 with a
central tweeter 202 circled by four additional tweeters 204, 206, 208 and 210. Further,
loudspeaker 200 includes four midrange drivers 212, 214, 216 and 218 and two woofers 220
and 222.
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[0041]
The tweeters 204, 206, 208 and 210, the midrange drivers 212, 214, 216 and 218, and the two
woofers 220 and 222 are all aligned linearly along the y-axis, symmetrically with respect to the
central tweeter 202. It is done. A pair of tweeters 204 and 206, and a pair of tweeters 208 and
210, respectively, are placed on one side of the central tweeter 202, above and below the
centerline defined by the x-axis. Similarly, the pair of mid-range drivers 212 and 214 are located
above the tweeters 202, 204, 206, 208 and 210, and the other pair of mid-range drivers 216
and 218 are paired with the tweeters 202, 204, 206, 208 and 210. And positioned symmetrically
about a centerline defined by the x-axis.
[0042]
Similar to the loudspeaker system 100 of FIG. 1, the loudspeaker system of FIG. 2 includes
tweeters 202, 204, 206, 208 and 210 of about 40 mm to 50 mm outer diameter, mid-range
drivers 212 of about 80 mm to 110 mm outer diameter, 214, 216 and 218, and woofers 220
and 222 of an outer diameter of about 120 mm to 250 mm. As mentioned earlier, the
dimensions of the transducer cones may vary based on the desired application and the desired
array dimensions.
[0043]
In general, the design of a system with n ways involves optimal position coordinates y0, + / −
(y1, y2, y3,..., Yn−1) and filter FIR (for specific directional objective functions) Obtain filter
coefficients for 0, 1, 2, 3,..., N−1). In the example where n is given equal to 4, when generating a
two-dimensional array, drivers with subscripts (1,..., m), m ≦ n are paired (here, m = 1 and m = 2
Can be separated into Also, the corresponding x-axis coordinates are +/- (x1, x2, ..., xm) while the
y-coordinates remain unchanged with the values of the one-dimensional design.
[0044]
The y-coordinates in the two-dimensional loudspeaker system 200 can be designed smaller than
the physical dimensions of the driver, as shown in FIG. 2, because separating the driver and
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moving it in the x-axis direction provides space Because Thus, the two-dimensional design
provides an additional degree of freedom, which generally leads to further performance
improvements.
[0045]
The directivity along the x-axis can be adapted by optimization of the position parameters x1, ...,
xm and by the value of m itself. Drivers with the subscripts (m + 1), ..., n-1 are not separated and
remain in their original position. This means that the array with respect to the x-axis is a
truncated version of the original standard array designed with respect to the y-axis. Thus, the
directivity function exhibits higher corner frequencies.
[0046]
The coefficients x1, ..., xm can be optimized such that a smooth, frequency independent
directivity function is obtained along the x-axis. When x1 <y1 and x2 <y2,..., the directivity in the
x-axis direction of the array is small. In the case of x1 = y1, x2 = y2,..., the two are equal at high
frequencies.
[0047]
In the embodiment provided in FIG. 2, the central tweeter 202 can be incorporated at a center
point 0 on the y-axis, which is the intersection of the x-axis and the y-axis, as shown in FIG. The
tweeters 204, 206, 208 and 210 incorporate their centers at approximately +/- 30 mm along the
x-axis and +/- 42 mm along the y-axis (+/- 30 mm, +/- 42 mm) Be
[0048]
The midrange drivers 212, 214, 216 and 218 are then placed at their centers, center point 0 to
about +/− 80 mm along the x-axis and about +/− 120 mm along the y-axis (+/− 80 mm , +/−
120 mm) can be incorporated. Woofers 220 and 222 are then incorporated at their centers at a
position about +/- 300 mm (+/- 0 mm, +/- 300 mm) from the center point.
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[0049]
Similar to the loudspeaker system 100 of FIG. 1, the transducer may be incorporated into a
housing 230 comprising compartments 232, 234 and 236 separated and sealed by separators
242 and 244 as shown. The compartment 232 containing the woofer 220 may be separated by
the separator 242 from the compartment 236 containing the midrange drivers 212, 214, 216
and 218 and the tweeters 202, 204, 206, 208 and 210. Similarly, the compartment 234
containing the woofer 222 may be separated by the separator 244 from the compartment 236
containing the midrange drivers 212, 214, 216 and 218 and the tweeters 202, 204, 206, 208
and 210.
[0050]
FIG. 2 also shows a block diagram 250 of the signal flow of the multi-way loudspeaker system
200. FIG. 2 shows four ways 252, 254, 256 and 258 of signal flow. The signal flow comprises a
digital input 264 which can be implemented using a standard connection format and is
connected with the driver via various paths or ways, such as the four ways shown in FIG. . Each
path or way 252, 254, 256 and 258 may include a digital FIR filter 260 and a power D / A
converter 262 connected with one or more loudspeaker drivers.
[0051]
FIG. 3 is a flow chart of a filter design algorithm 300 used to design a loudspeaker system of the
present invention. The purpose of the filter design algorithm 300 is to determine the coefficients
for each FIR filter that correspond to the flow path of each signal of the loudspeaker. As shown in
more detail below, an initial driver's position and an initial directivity objective function are first
determined (310). The initial speaker and driver locations or design arrangements are designed
according to a number of different variables depending on the application, such as the desired
loudspeaker dimensions, intended use, manufacturing constraints, aesthetic taste or other
product design aspects. It can be done. The coordinates of the driver are then defined for each
driver along the main axis. Then, an initial estimate for the directional objective function is set,
which involves setting frequency points within the interval of interest on a logarithmic scale. The
cost function is then minimized at the defined frequency points (312). At step 314, if the result
does not meet the system performance requirements, the driver's location is modified and the
cost minimization function is applied again (316). This cycle may be repeated until the results
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match the requirements. If the results match the requirements, linear phase filter coefficients are
calculated (318). Additional calculations may also be performed (320) to equalize the drivers,
and to compensate for phase shift, and to allow adjustment of the beam orientation.
[0052]
In the first step 310, the initial driver position and the initial directivity objective function are set.
As mentioned earlier, the number, position, size and orientation of the drivers are primarily
determined by the product design aspect. Once the direction is determined, then the initial
coordinate values may be defined as the initial driver coordinates p (n), n = 1,..., N, for the N
drivers on the main axis. For example, in the one-dimensional (1D) array shown in FIG. 1, N = 7: p
(n) = [− 0.30, −0.15, −0.06, 0, 0.06, 0.15, 0.30] m (meters). In the two-dimensional (2D) array
shown in FIG. 2, N = 7: p (n) = [− 0.30, −0.12, −0.042, 0, 0.042, 0.12, 0 .30] m.
[0053]
As depicted in FIG. 2, if the two-dimensional configuration is symmetrical with respect to both
the x and y axes, the design process for the two-dimensional configuration is for one dimension,
for example with respect to the main axis as described above It can be implemented. The same
directivity characteristic is obtained for the other axes, except for the higher corner frequency,
because of the symmetry.
[0054]
In order to determine the initial directivity objective function, it is possible to define initial
estimates for the directivity objective function T (f, q) which are determined based on the desired
performance of the driver at a particular angle q. is necessary. FIG. 4 shows an example set of
objective functions for angle dependent attenuation at five specific angles q. The directional
objective function defines the planned sound level attenuation in dB (y axis), which is the origin
(center tweeter at a sufficiently large distance from the loudspeaker (larger than the dimensions
of the loudspeaker) in an anechoic environment Can be measured at various frequencies at an
angle q from a perpendicular to. The frequency vector f defines a set of frequency points, for
example 100, on a logarithmic scale within the relevant frequency interval, for example 100 Hz,.
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[0055]
The angle vectors q (i), i = 1,..., Nq define the set of angles at which the optimization is performed.
Figure 4 shows initial estimates for directivity at five angles: (Nq = 5): q = [0, 10, 20, 30, 40] °,
in most cases 2 It may be sufficient to define directivity only for a number of angles, eg Nq = 2. In
this case, the targeted directivity may be defined at an outer angle, for example 40 degrees, and
at 0 degrees, where a directivity of zero on axis is defined. For example, q = [0, 40] °.
[0056]
With the exception of the on-axis objective function, the objective function at each angle is linear
on a bilogarithmic scale from T = 0 dB at f = 0 to a value of T <0 dB at a particular frequency fc
(eg fc = 350 Hz) It decreases and then keeps a constant value. The on-axis objective function 402
maintains a constant value of 0 dB over the entire frequency range. The target directivity
functions of 10 (10) degrees 404, 20 (20) degrees 410, 30 (30) degrees 412, and 40 (40)
degrees 414 all begin at T = 0 dB and are represented by 350 Hz in FIG. It descends on a
logarithmic scale until the function reaches fc, and then maintains a constant value over the
frequency range in question.
[0057]
After the initial driver position and the initial directivity objective function are determined, a next
step 312 minimizes the cost function F (f) at a given frequency vector point f. This minimization
is done by starting with the smallest frequency increase step, eg 100 Hz, using the obtained
solution as an initial solution for the next step, respectively, using the following equation:
[0058]
および
[0059]
Where Hm (n, f, q) is the measured amplitude frequency response normalized to the on-axis
(angle 0) response obtained for the driver n, frequency f and angle q of interest , An example of
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which is shown in FIG.
FIG. 5 shows the frequency response 500 measured at various vertical deviation angles of an
attached tweeter and normalized to on-axis values. In FIG. 5, line 502 represents the on-axis
response, line 504 is the frequency response measured at 10 degrees, line 506 is the response at
20 degrees, line 508 is the response at 30 degrees, line 510 Is the frequency response measured
at 40 degrees, all measured in the frequency range between 1 kHz and 20 kHz.
[0060]
Furthermore, the minimization is performed by varying the real-valued frequency points of the
channel filter C opt (n, f) within the interval [0, 1], where n is the sign of the driver and f is the
frequency It is. Furthermore, the following constraints Copt (n, f) = 0, f> fo, f <fu need to be
satisfied, depending on the characteristics of the particular driver n. For example, in the woofer
example, the upper operating limit is fo = 1 kHz, the lower operating limit for tweeters is fu = 2
kHz, and for midrange drivers fu = 300 Hz, fo = 3 kHz possible.
[0061]
The cost function minimization procedure described above is available from The MathWorks, Inc.
May be implemented by the function "fminsearch" which is part of the Matlab (R) software
package owned and distributed by. The "fminsearch" function in the Matlab software package
uses the Nelder-Mead simplex algorithm or a derivative thereof. As an alternative, exhaustive
exploration may be applied on a predefined grid within the bounds of the parameters. Other
methodologies may also be used to minimize the cost function.
[0062]
If the difference between the obtained result and the goal is small enough, or if it is acceptable as
determined by a person skilled in the art for the particular design application, then each in the
linear array FIR filter coefficients for the signal path are obtained.
[0063]
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If the difference between the obtained result and the goal is not acceptable for the particular
design application, for example, or if it is too large, the position or geometry of the driver and /
or the parameter q (I) and fc (see FIG. 4) of the objective function T (f, g) are then corrected.
Once corrected, the cost minimization function is reapplied and the process is repeated until the
obtained results and goals are small enough or within the tolerance for the application.
[0064]
As shown in FIG. 3, if the position of the driver and the geometry of the driver are determined
such that the algorithm gives results within the tolerance of the objective function, then each
signal path n = 1,. FIR filter coefficients for N need to be determined, which is shown in step 318
of FIG. One way to determine the FIR filter coefficients is to use a Fourier approximation method
(frequency sampling method) to obtain a linear phase filter of a given degree. When applying a
Fourier approximation or other frequency sampling method, it is necessary to select an order
such that the approximation is sufficiently accurate.
[0065]
Fourier approximation is described by The MathWorks, Inc. May be implemented by the function
"firls" which is part of the Matlab® software package, owned and distributed by Similar
methodologies can be used to minimize the cost function by being implemented in other software
systems.
[0066]
Additionally, modifications can be made to the FIR filter to equalize the measured frequency
response of one or more drivers (in particular tweeters, midrange drivers). The impulse response
of these filters can be obtained by known methods and needs to be convoluted with the linear
phase channel filter impulse response when determining the coefficients of the FIR filter as
described above. Furthermore, the voice coil (acoustic center of the driver) can not be aligned. To
compensate for this, the filter can be given an appropriate delay by adding leading zero to the
FIR impulse response.
10-04-2019
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[0067]
Two-dimensional multi-way loudspeaker systems may be planned for use in conjunction with
various applications, such as stereo loudspeaker systems, multi-channel home entertainment
systems and public information broadcast systems. One skilled in the art can change the number,
type, and location of drivers, the number of channels, the number of signal flow paths or circuits,
as well as the axis to adapt directivity for a particular application. Can modify the position
parameters along
[0068]
FIG. 6 is another two-dimensional multi-way loudspeaker, this loudspeaker system including four
woofers 620, 622, 624 and 626 instead of two woofers. It is the same as a loudspeaker. The
arrangement depicted in FIG. 6 is a design that one skilled in the art may consider desirable for
use in sound enhancement applications.
[0069]
In the embodiment provided in FIG. 6, a central tweeter 602 may be attached to a center point 0
on the x-axis, shown as the intersection of the x and y axes of FIG. The tweeters 604, 606, 608
and 610 have their centers at about +/- 42 mm along the y-axis and about +/- 30 mm along the
x-axis (+/- 30 mm, +/- 42 mm) It is attached.
[0070]
The midrange drivers 612, 614, 616 and 618 are then placed at their centers along the y-axis to
about +/- 110 mm from its center point 0 and about +/- 80 mm along the x-axis (+/- -80 mm, +/110 mm). Woofers 620, 622, 624 and 626 are then placed at their centers (+/− 180 mm, +/−
300 mm) along the y-axis at about +/- 300 mm and along the x-axis at about +/- 180 mm.
Attached to).
[0071]
10-04-2019
19
Similar to the respective loudspeaker systems 100 and 200 of FIGS. 1 and 2, the transducer
comprises a section 630, 632 and 634 separated and sealed by separators 636 and 642 as
shown. It can be attached inside.
[0072]
FIG. 7 shows a block diagram 700 of signal flow of the multi-way loudspeaker system 600 of FIG.
FIG. 7 shows four ways 702, 704, 706 and 708 of the signal flow. The signal flow is equipped
with a digital input 710 that can be implemented by using a standard connection format and is
connected to the driver via various paths or ways such as the four ways shown in FIG. . Digital
FIR filters 712, 714, 716, 718 and power D / A converters 720, 722, 724, each path or way 702,
704, 706 and 708, respectively, being connected with one or more loudspeaker drivers. 726 may
be included.
[0073]
As shown in FIG. 7, signal flow way 702 feeds woofers 620, 622, 624 and 626 of loudspeaker
system 600 of FIG. The signal flow way 704 feeds the midrange drivers 612, 614, 616 and 618
of the loudspeaker system 600 of FIG. The signal flow way 706 feeds the tweeters 604, 606, 608
and 610 of the loudspeaker system 600 of FIG. 6, and the signal flow way 708 feeds the central
tweeter 602 of the loudspeaker system 600 of FIG. Do.
[0074]
FIG. 8 is a graph of the allowed results obtained for the frequency response when applied to a
loudspeaker system similar to that shown in FIG. 6 of the four filters shown in FIG. 800 is shown.
In particular, line 802 represents the result for the frequency response of FIR filter 712. Line
804 shows the results for the frequency response of FIR filter 714, line 806 shows the results for
the frequency response of FIR filter 716, and line 718 shows the results for the frequency
response of FIR filter 718.
10-04-2019
20
[0075]
FIG. 9 is a graph 900 illustrating the resulting horizontal (y-axis) frequency response at various
angles. This graph shows the filter frequency response V (f, q) obtained after passing step 314 of
FIG. Passing means that the result matches the request. In particular, line 902 represents the
resulting response on the horizontal axis V (f, q (1)), line 904 is the frequency response V (f, q
(2)) at 5 degrees, Line 906 is the response V (f, q (3)) at 10 degrees, line 908 is the response V (f,
q (4)) at 15 degrees, and line 910 is the response V (f, q at 20 degrees (5)), line 912 is the
response V (f, q (6)) at 25 degrees, line 914 is the response V (f, q (7)) at 30 degrees, and line
916 is 35 Response V (f, q (8)) in degrees, all shown in the frequency range between 100 Hz and
20 kHz.
[0076]
FIG. 10 is a graph 1000 illustrating the resulting vertical (x-axis) frequency response at various
angles. In particular, line 1002 represents the resulting response on the vertical axis V (f, q (1)),
line 1004 is the frequency response V (f, q (2)) at 5 degrees, Line 1006 is the response V (f, q
(3)) at 10 degrees, line 1008 is the response V (f, q (4)) at 15 degrees, and line 1010 is the
response V (f, q at 20 degrees (5)), line 1012 is the response V (f, q (6)) at 25 degrees, line 1014
is the response V (f, q (7)) at 30 degrees, and line 1016 is 35 Response V (f, q (8)) in degrees, all
shown in the frequency range between 100 Hz and 20 kHz.
[0077]
11-22 show examples of multi-way loudspeakers for loudspeaker systems suitable for home
entertainment.
[0078]
FIG. 11 shows an example of a one-dimensional (1D) 7-way loudspeaker system 1100
incorporated symmetrically along the x-axis, and a block diagram 1160 of the signal flow to each
loudspeaker driver of the system. .
This embodiment can serve as a basis for the two-dimensional (2D) multi-way loudspeaker
system designs 1400 and 1700 shown in FIGS. 14 and 17, which system designs may be used
10-04-2019
21
for home entertainment applications or other known by those skilled in the art. It can be
designed for use in appropriate applications.
[0079]
As shown in FIG. 11, the one-dimensional seven-way loudspeaker system 1100 is (1) one central
tweeter 1102 placed at the origin, (2) both sides of the central tweeter 1102 along the x-axis.
The first pair of tweeters 1104 and 1106, which are placed at the position of +/− 0.035 m, (3)
placed at the position of +/- 0.07 m along the x-axis on both sides of the first pair of tweeters A
second pair of tweeters 1108 and 1110, (4) a first pair of midrange drivers 1112 and 1114, (5)
x-, located at a position of +/- 0.12 m along the x-axis. The second pair of mid-range drivers 1116
and 1118, located at +/− 0.20 m along the axis, (6) located at +/− 0.34 m along the x-axis,
Three pairs of midrange drivers 1120 and 112 , And (7) x- along the axis is placed at a position
of +/- 0.54 m, may include a woofer 1124 and 1126, of the pair.
[0080]
As in the previously shown embodiment, the driver can be included in a housing having various
compartments.
The tweeters 1102, 1104, 1106, 1108 and 1110 and the midrange drivers 1112 and 1114 may
be placed in one compartment 1130. The compartment 1136 placed adjacent to the
compartment 1130 and separated by a separator 1132 includes an intermediate driver 1116. A
compartment 1138 placed on the opposite side of the compartment 1130 and separated by a
separator 1134 includes a midrange driver 1118. Section 1144 includes mid-range driver 1120,
one side separated from section 1136 by separator 1140, and the other side separated from
section 1152 including woofer 1124 by separator 1148. Similarly, compartment 1146 includes
mid-range driver 1122, one side separated from compartment 1138 by separator 1142 and the
other side separated from compartment 1154, which includes woofer 1126, by separator 1150.
[0081]
Loudspeaker system 1100 may receive digital input 1180. The signal flow diagram 1160 shows
that the central tweeter 1102 is provided by way of signal flow 1174 which includes an FIR filter
1176 and a power D / A converter 1178. The first pair of tweeters 1104 and 1106 is provided
by way of signal flow 1172 that includes an FIR filter 1178 and a power D / A converter 1178,
10-04-2019
22
and the second pair of tweeters 1108 and 1110 includes an FIR filter 1180 and a power D / A
converter 1178 is supplied by way of signal flow 1170. A first pair of midrange drivers 1112 and
1114 is provided by way of signal flow 1168 including an FIR filter 1182 and a power D / A
converter 1178 while a second pair of midrange drivers 1116 and 1118 are A signal stream way
1166 is provided which includes an FIR filter 1184 and a power D / A converter 1178. A third
pair of midrange drivers 1120 and 1122 is provided by way of signal flow 1114 which includes
an FIR filter 1186 and a power D / A converter 1178. Finally, a pair of woofers 1124 and 1126
is provided by way 1162 of signal flow including FIR filter 1188 and power D / A converter
1178.
[0082]
FIG. 12 is a graph 1200 illustrating the frequency characteristics of the seven filters of the
loudspeaker system of FIG. 11, where a cost minimization function is applied and the results
obtained are sufficiently small or acceptable for the desired application It is already known to be
within. The line represented by 1202 is the frequency response of FIR filter 1176, line 1204 is
the frequency response of FIR filter 1178, line 1206 is the frequency response of FIR filter 1180,
and line 1208 is the frequency response of FIR filter 1182. Line 1210 is the frequency response
of FIR filter 1184, line 1212 is the frequency response of FIR filter 1186, and line 1214 is the
frequency response of FIR filter 1188.
[0083]
FIG. 13 is a graph 1300 illustrating the resulting horizontal (x-axis) frequency response of the
loudspeaker system of FIG. 11 measured at various angles. This graph shows the filter frequency
response V (f, q) obtained after meeting the requirements of step 314 of FIG. Specifically, line
1302 represents the resulting on-axis response V (f, q (1)), and line 1304 is the frequency
response V (f, q (2)) at 10 degrees, Line 1306 is the response V (f, q (3)) at 15 degrees, line 1308
is the response V (f, q (4)) at 20 degrees, line 1310 is the response V (f, q at 30 degrees (5)), all
shown in the frequency range between 100 Hz and 20 kHz.
[0084]
FIG. 14 shows an example of a two-dimensional (2D) multi-channel 7-way loudspeaker system
1400 incorporated symmetrically along the x-axis and y-axis. The loudspeaker system 1400 is
10-04-2019
23
obtained by separating the tweeters 1104, 1106, 1108 and 1110 and the midrange drivers
1112 and 1114 of the loudspeaker system 1100 of FIG. 11 into pairs.
[0085]
Loudspeaker system 1400 controls directivity in two directions, and central tweeter 1402, four
pairs of tweeters 1404 and 1406, 1408 and 1410, 1412 and 1414, and 1416 and 1418,
intermediate ranges of four pairs. Drivers 1420 and 1422, 1424 and 1426, 1428 and 1430, and
1432 and 1434, and pairs of woofers 1436 and 1438 are included. The first two pairs of
tweeters 1404 and 1406, 1408 and 1410 are arranged in a square shape with respect to the
central tweeter 1402. The third and fourth pairs of tweeters 1412, 1414, 1416 and 1418 are
placed on more distant quadrants symmetrically along the x and y axes. The first and second
pairs of mid-range drivers 1420, 1422, 1424 and 1428 are placed on more distant quadrants
symmetrically along the x and y axes. As described further below, the inner quadrant is defined
by an angle of 45 (45) degrees to the x-axis.
[0086]
Additionally, mid-range drivers 1428, 1430, 1432 and 1434, and woofers 1436 and 1438 are
linearly spaced on the x-axis. The (x, y) coordinates of the driver of the loudspeaker 1400 may be
as follows.
[0087]
The tweeter 1402: (0,0) The tweeter 1404, 1406, 1408 and 1410: (+/− 35, + / − 35) mm The
tweeter 1412, 1414, 1416 and 1418: (+/− 70, + / − 70) mm Intermediate Region 1420, 1422,
1424 and 1426: (+/− 120, +/− 120) mm Intermediate Region 1428 and 1430: (+/− 200, 0)
mm Intermediate Region 1432 and 1434: (+/− 340, 0) ) Mm Woofers 1436 and 1438: (+/−
540,0) mm As with the loudspeaker system shown in FIG. 11, the drivers are separated and
sealed compartments 1440, 1442, 1444, 1446, 1448, 1450. And 1452 with a baffle 1476 That.
The tweeters 1402, 1404, 1406, 1408, 1410, 1412, 1414, 1416 and 1418 and the midrange
drivers 1420, 1422, 1424 and 1426 may all be included in the section 1440. On the right side,
compartment 1440 can be separated from compartment 1444 by the separator represented by
triangular line 1460. Section 1444 includes mid-range driver 1430, the right side of which can
be separated from compartment 1448, which includes mid-range driver 1434, by a separator
10-04-2019
24
indicated by line 1464. To the right of compartment 1448 is compartment 1452 which includes
woofer 1438. Sections 1448 and 1452 may be separated from one another by the separator
represented by line 1468.
[0088]
Similarly, compartment 1440 can be separated from compartment 1442 on its left side by a
separator represented by triangular line 1462. Section 1442 includes mid-range driver 1428, the
left side of which can be separated from compartment 1446, which includes mid-range driver
1432, by a separator indicated by line 1466. To the left of section 1446 is a section 1450 that
includes a woofer 1436. Sections 1446 and 1450 may be separated from one another by the
separator represented by line 1470.
[0089]
As with the drivers of FIGS. 1 and 2, the tweeters 1402, 1404, 1406, 1408, 1410, 1412, 1414,
1416 and 1418 may be about 40 mm to 50 mm outside diameter and the midrange drivers
1420, 1422, 1424. 1426, 1428, 1430, 1432 and 1434 may be about 80 mm to 110 mm in
outer diameter, and woofers 1436 and 1438 may be about 120 mm to 160 mm in outer
diameter.
[0090]
FIG. 15 is a block diagram 1500 of signal flow to each loudspeaker driver of the loudspeaker
system 1400 of FIG.
As shown in FIG. 15, for each driver with the same set of position coordinates previously set,
each provided by a different path or way results in a seven way loudspeaker. Loudspeaker
system 1400 receives digital input 1502. The central tweeter 1402 is supplied by way 1504 of
the signal flow. The tweeters 1404, 1406, 1408 and 1410 are supplied by way 1506 of the
signal flow. The tweeters 1412, 1414, 1416 and 1418 are provided by way of signal flow 1508.
Mid-range drivers 1420, 1422, 1424 and 1426 are provided by way of signal flow 1510, while
mid-range drivers 1428 and 1430 are provided by way of signal flow 1512 and mid-range
drivers 1432 and 1434 are provided. Provided by way 1514 of the signal flow. Pairs of woofers
1436 and 1438 are provided by way of signal flow 1516. Each signal flow way includes an FIR
filter 1518 and a power D / A converter 1520.
10-04-2019
25
[0091]
FIG. 16 is a graph 1600 depicting the resulting vertical (y-axis) frequency response of the
loudspeaker system 1400 of FIG. 14 measured at various angles. This graph shows the frequency
response V (f, q) of the filter obtained after meeting the requirements of step 314 of FIG. In
particular, line 1602 represents the resulting horizontal on-axis response V (f, q (1)), line 1604 is
the frequency response V (f, q (2)) at 10 degrees, Line 1406 is the frequency response V (f, q (3))
at 15 degrees, line 1608 is the frequency response V (f, q (4)) at 20 degrees, and line 1610 is the
frequency response V at 30 degrees f, q (5)), all shown in the frequency range between 100 Hz
and 20 kHz. As seen by FIG. 16, the vertical frequency response for the two-dimensional
loudspeaker system 1400 of FIG. 14 is similar to the horizontal frequency response shown by
FIG. 13 for the one-dimensional loudspeaker system 1100 of FIG. However, for lower corner
frequencies where the directivity of the system appears above that frequency, it has a fairly high
frequency value.
[0092]
FIG. 17 shows an embodiment of a two-dimensional (2D) five-channel multi-way loudspeaker
system 1700 mounted symmetrically along the x-axis. Loudspeaker system 1700 is designed to
have a pair of integrated two-way stereo speakers mounted symmetrically along the x-axis,
especially for use for home theater applications There is. As further described below (FIGS. 1820), loudspeaker system 1700 comprises five input channels L (left), R (right), C (center), LS (left
surround), and RS. (Right surround).
[0093]
The loudspeaker system 1700 is the same as the system of FIG. 14 except that it comprises two
additional tweeters 1744 and 1746 and two additional woofers, the difference being that the
outer woofer is y-- It is to have an additional pair of tweeters 1744 and 1746 separated into
1736 and 1738 pairs and 1740 and 1742 pairs with respect to axis and placed between the
respective pairs of woofers 1736 and 1738, 1740 and 1742. By having the tweeters 1744 and
1746 designated for each of the woofer pairs 1736 and 1738, and 1740 and 1742 respectively,
the loudspeaker system 1700 provides independent stereo speaker channels (eg, tweeters
provided by separate channels) Array can be provided). The purpose of the independent stereo
10-04-2019
26
speaker channel is to provide an integrated surround sound system with directional sound beams
generated by conventional stereo speakers and arrays, and indirectly ambient back using the wall
reflections in the listening room (Ambient rear) is to play the channel.
[0094]
Similar to the loudspeaker system 1400 shown in FIG. 14, the loudspeaker system 1700 of FIG.
17 consists of two pairs arranged in a square shape with respect to (1) central tweeter 1702, (2)
central tweeter 1702. Two additional pairs of tweeters 1712 and 1714 placed on more distant
quadrants, symmetrically along the 1-tweeters 1704 and 1706, and 1708 and 1710, (3) x-axis
and y-axis. , And 1716 and 1718, and (4) two pairs of midrange drivers 1720 and 1722, and
1724 placed on more distant quadrants symmetrically along the x-axis and y-axis. And 1726,
respectively. A quadrant is defined by an angle of 45 (45) degrees to the x-axis.
[0095]
Additionally, loudspeaker system 1700 includes midrange drivers 1728, 1730, 1732 and 1743,
which are linearly spaced in the x-axis. The (x, y) coordinates of the driver of the loudspeaker
system 1700 may be as follows.
[0096]
Tweeter 1702: (0,0) Tweeter 1704, 1706, 1708 and 1710: (+/− 35, + / − 35) mm Tweeter
1712, 1714, 1716 and 1718: (+/− 70, + / − 70) mm Intermediate Zones 1720, 1722, 1724
and 1726: (+/− 120, +/− 120) mm Intermediate Zones 1728 and 1730: (+/− 200, 0) mm
Intermediate Zones 1732 and 1734: (+/− 340, 0) ) Mm Tweeters 1744 and 1746: (+/− 540,0)
mm Woofers 1736, 1738, 1740 and 1742 (+/− 540, +/− 90) mm Figure 1, Figure 2, Figure 6,
Figure 11 and Figure 14 As with the loudspeaker system shown in FIG. , 1768, 1770, 1772,
1774 and 1776, respectively, of a divider or housing 1750 comprising separate and sealed
compartments 1752, 1754, 1756, 1768, 1760, 1762 and 1764, respectively. It can be attached
inside.
[0097]
FIGS. 18-20 show block diagrams of signal flow for the five input signals of the loudspeaker
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27
system 1700 of FIG.
FIG. 18 is a block diagram 1800 of signal flow for surround channels for the loudspeaker system
1700 of FIG. Since the signal flows for the right and left surround channels of system 1700 are
identical except for the different delay values, block diagram 1800 of FIG. 18 is left as described
further below. Represents the signal flow path for both and right surround. Thus, both left and
right surround input signals are transmitted via a signal path system similar to that shown in FIG.
The sum of each output signal is then calculated and connected to the converter as noted in FIG.
The output of the FIR filter, whose frequency response is shown in FIG. 12, is connected to the
delay line D0 and the pair of delay lines D +/− (1,..., 6) respectively.
[0098]
The signal flow block diagram 1800 of FIG. 18 shows that delays are added to each path
according to the following equation:
[0099]
Δt = p / c · sin α, (p = the coordinates of the driver (meters), c = 345 m / sec (sound velocity))
where the main sound beam is perpendicular to the main axis otherwise, but at an angle α Can
be oriented in the desired direction of
Typical values for α are-(40, ..., 60) degrees for the left surround and + (40, ..., 60) degrees for
the right surround, Means that the sound beam is formed towards the side walls in the direction
of the angles α and −α and bounces off the wall to reach the listener as a surround signal.
[0100]
As shown in FIG. 18, a signal flow path diagram 1800 shows the respective flow paths for digital
inputs 1802 and 1804 for the right and left surround sound channels. The output of FIR filter
1822 for path 1806 is connected to delay line (D0) 1840, which is connected to center tweeter
1702. The outputs of FIR filter 1824 for path 1808 are connected in parallel to delay lines (D-1)
1842 and (D + 1) 1844. Delay line 1842 is connected to the right pair of tweeters 1708 and
1710, and delay line 1844 is connected to the left pair of tweeters 1704 and 1706. Similarly, the
output of FIR filter 1826 for path 1810 is connected in parallel to delay lines (D-2) 1846 and (D
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28
+ 2) 1848. Delay line 1846 is connected to the right pair of tweeters 1716 and 1718, and delay
line 1848 is connected to the left pair of tweeters 1712 and 1714. Delay lines (D-3) 1850 and (D
+ 3) 1852 are connected to mid-range drivers 1720 and 1722 and 1724 and 1726, respectively,
which are connected in parallel to path 1812, which is the output path to FIR filter 1828 is there.
[0101]
Mid-range drivers 1728 and 1730 are connected to delay lines (D + 4) 1856 and (D-4) 1854,
respectively, which is the output path 1814 to FIR filter 1830. Mid-range drivers 1732 and 1734
are connected to delay lines (D + 5) 1862 and (D-5) 1860, respectively, which is the output path
1816 to FIR filter 1832.
[0102]
The right pair of woofers 1740 and 1742 are connected to delay line (D-6) 1864 and the left pair
of woofers 1736 and 1738 are connected to delay line (D + 6) 1866. Delay line (D + 6) 1866 and
delay line (D-6) 1864 are connected in parallel to output path 1820 to FIR filter 1834.
[0103]
FIG. 19 is a block diagram of signal flow for right and left channels for the loudspeaker system of
FIG. The left and right channels are integrated as in a conventional two way speaker. The left
channel consists of tweeters 1744 that are not part of the beamforming array, and woofers 1736
and 1738. The right channel consists of tweeter 1746 and woofers 1740 and 1742.
[0104]
As shown by FIG. 19, the signal processing 1900 for the left and right channels is a stereo
widening circuit consisting of an HD filter 1910 and an HI filter 1912 to expand the stereo basis,
and a low pass. A crossover circuit with a filter 1914 and an HP high pass filter 1916 is used.
[0105]
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29
FIG. 20 is a block diagram of signal flow for the center channel for the loudspeaker system 1700
of FIG.
The center channel is a tweeter 1702, 1704, 1706, 1708, 1710, 1712, 1714, 1716 and 1718,
and a midrange driver 1720, 1722 with an FIR filter having coefficients determined as defined in
FIG. Regenerated by the inner array of 1724 and 1726.
[0106]
The output 2010 of the digital signal to the central channel is divided into four signal paths
2002, 2004, 2006 and 2008, each path having an FIR filter 2012, 2014, 2016 and 2018
respectively, and a power D / A converter 2020 , 2022, 2024 and 2026, respectively. Path 2002
feeds central tweeter 1702. Path 2004 feeds the innermost tweeter 1704, 1706, 1708 and 1710
of the innermost quadrant. Path 2006 feeds the outermost quadrant tweeters 1712, 1714, 1716
and 1718, and path 2008 feeds the middle quadrant mid-range drivers 1720, 1722, 1724 and
1726.
[0107]
FIG. 21 is a graph 2100 illustrating the frequency response of the four FIR filters used in the
center channel (FIG. 20) of the loudspeaker system of FIG. Line 2102 represents the frequency
response of FIR filter 2012, line 2104 represents the frequency response of FIR filter 2014, line
2106 represents the frequency response of FIR filter 2016, and line 2108 represents the
frequency response of FIR filter 2018.
[0108]
FIG. 22 shows the resulting horizontal (x-axis) and vertical (y-axis) measurements of the center
channel output (FIG. 20) of the loudspeaker system 1700 of FIG. 17 at various angles. ) Is also a
graph 2200 representing frequency response. This graph shows the frequency response V (f, q)
of the filter obtained after meeting the requirements of step 314 of FIG. In particular, line 2202
represents the resulting response on the horizontal axis V (f, q (1)) and line 2204 is the
frequency response V (f, q (2)) at 5 degrees, Line 2206 is the frequency response V (f, q (3)) at
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30
10 degrees, line 2208 is the frequency response V (f, q (4)) at 15 degrees, and line 2210 is the
frequency response V at 20 degrees. f, q (5)), the line 2212 is the frequency response V (f, q (6))
at 25 degrees, the line 2214 is the frequency response V (f, q (7)) at 30 degrees, Line 2216 is the
frequency response V (f, q (8)) at 35 degrees, all shown in the frequency range between 100 Hz
and 20 kHz.
[0109]
While various embodiments of the invention have been described, it will be apparent to those
skilled in the art that many more embodiments and implementations are possible within the
scope of the invention. Accordingly, the invention is not to be restricted except in light of the
attached claims and their equivalents.
[0110]
The present invention is a multi-way loudspeaker system that provides a form of loudspeaker of
reasonable size and a filter design methodology operating in the area of digital signal processing.
Furthermore, the loudspeaker system can be designed as a multi-way loudspeaker system with
loudspeaker drivers arranged symmetrically in a two-dimensional plane, high quality sound, ie a
wide range of both vertical and horizontal both Certain directivity can be achieved and used in
combination with stereo loudspeaker systems, multi-channel home entertainment systems and
public information broadcast systems.
[0111]
FIG. 7 shows an example of a one-dimensional four-way loudspeaker system mounted
symmetrically at the origin along the y-axis, and a block diagram of the signal flow to each
loudspeaker driver in the system. FIG. 7 shows an example of a two-dimensional 4-way
loudspeaker system symmetrically mounted at an origin along the x-axis and y-axis, and a block
diagram of the signal flow to each loudspeaker driver in the system. Fig. 6 is a flow chart of a
filter design algorithm used to design a loudspeaker system. Fig. 6 is a graph showing the
directivity objective function for angle dependent attenuation. FIG. 6 is a graph showing the
measured amplitude frequency response at various vertical off-axis deflection angles of an
attached tweeter. Fig. 7 shows an example of another two-dimensional four-way loudspeaker
system mounted symmetrically at the origin along the x-axis and the y-axis. FIG. 7 is a block
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31
diagram of signal flow to each of the loudspeaker drivers shown in FIG. 6; 7 represents the
frequency response of the four filters of the loudspeaker system of FIG. FIG. 7 shows the
horizontal (y-axis) frequency response obtained as a result of the loudspeaker system of FIG. 6
measured at various angles. FIG. 10 illustrates the resulting vertical (x-axis) frequency response
of the loudspeaker system of FIG. 6 corresponding to the horizontal response shown in FIG. 9.
FIG. 6 shows an example of a one-dimensional (1D) 7-way loudspeaker system, mounted
symmetrically at the origin along the y-axis, and a block diagram of the signal flow to each
loudspeaker driver in the system. FIG. 12 shows the frequency response of the seven filters of the
loudspeaker system of FIG. FIG. 12 shows the resulting horizontal (x-axis) frequency response of
the loudspeaker system of FIG. 11 measured at various angles. FIG. 7 illustrates an example of a
two-dimensional (2D) multi-channel 7-way loudspeaker system mounted symmetrically along the
x-axis and y-axis. FIG. 15 is a block diagram of signal flow to each loudspeaker driver of the
loudspeaker system of FIG. 14; FIG. 15 shows the resulting vertical (y-axis) frequency response of
the loudspeaker system of FIG. 14 measured at various angles. FIG. 7 illustrates an example of a
two-dimensional (2D) 5-channel multi-way loudspeaker system, mounted symmetrically along the
x-axis and y-axis and designed for home theater applications. FIG. 18 is a block diagram of signal
flow for right and left surround channels for the loudspeaker system of FIG. 17;
FIG. 18 is a block diagram of signal flow for right and left channels for the loudspeaker system of
FIG. 17; FIG. 18 is a block diagram of signal flow for the center channel for the loudspeaker
system of FIG. 17; Fig. 18 shows the frequency response of the four filters of the center channel
of the loudspeaker system of Fig. 17; FIG. 18 shows the resulting horizontal (x-axis) frequency
response of the center channel of the loudspeaker system of FIG. 17 measured at various angles.
10-04-2019
32
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