TECHNICAL FIELD
[0002] The present disclosure is generally directed to multi-path acoustic
waveguides.
BACKGROUND
[0003] In audio speakers, one factor that determines the sound quality is the sound
pressure level (SPL), which generally depends in part on the speaker size relative to
the distance between the speaker and the listener. Generally, a larger distance requires
a larger speaker size. There is, however, a practical limit on the size of a large speaker.
One solution is to use an array of smaller sized speakers to achieve similar acoustic
results, because sound waves from the individual smaller speakers may combine to
yield a combined sound wave that behaves similar to that emanating from a single large
speaker. It is generally accepted that the spacing between two neighboring speakers
needs to be smaller than the wavelength of the sound wave in question. The
wavelength of a wave is determined as wave velocity divided by wave frequency. The
wave velocity of sound in room temperature air is approximately 1130 ft/sec. For a low
frequency audio sound having a frequency of 200 Hz, as an example, the corresponding
wavelength is approximately 68 inches. Similarly, a midrange audio sound with a
frequency of 2000 Hz, the corresponding wavelength is approximately 6.8 inches. A
high frequency audio sound with an exemplary frequency of 20000 Hz has a wavelength
is approximately 0.68 inches. It is difficult to achieve this small distance between
speakers for high frequency sounds. This relatively small wavelength poses a problem
for providing the desired spacing between high frequency speakers.
[0004] Acoustic waveguides have been developed to provide improved sound
distribution from selected high-frequency drivers. Examples of such improved
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waveguides include the waveguides and associated technology set forth in U.S. Patent
Nos: 7, 177,437, 7,953,238, 8,718,31 0, 8,824,717, and 9,204,212, and U.S. Patent
Application Publication No. US2019-0215602, each of which is incorporated herein in
its entirety by reference. While these waveguides provide substantial improvements
particularly transmitting for high frequency audio sounds, there is still a need to
distribute the emanation of the sound waves across the front of the speaker, producing
a planar or cylindrical wavefront.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Figure 1 is a front elevation view of an acoustic waveguide in accordance
with an embodiment of the present technology.
[0006]
1 .
[0007]
Figure 2 is a top rear perspective view of the acoustic waveguide of Figure
Figure 3 is a left side elevation view of the acoustic waveguide of Figure 1.
[0008] Figure 4 is a cross-sectional plan view of the acoustic waveguide taken
substantially along line 4-4 of Figure 1.
[0009] Figure 5 is a front elevation view of an acoustic waveguide in accordance
with another embodiment of the present technology.
[0010]
5.
[0011]
Figure 6 is a top rear perspective view of the acoustic waveguide of Figure
Figure 7 is a left side elevation view of the acoustic waveguide of Figure 5.
[0012] Figure 8 is a cross-sectional plan view of the acoustic waveguide taken
substantially along line 8-8 of Figure 5.
[0013] Figures 9A and 98 are schematic detail views of a lateral flare profile and
a vertical flare profile, respectively, of the acoustic waveguide of Figure 1.
[0014] Figures 1 OA and 1 OB are schematic detail views of a lateral flare profile and
a vertical flare profile, respectively, of the acoustic waveguide of Figure 5.
DETAILED DESCRIPTION
[0015] The technology disclosed herein relates to acoustic waveguides and
associated systems. Several embodiments of the present technology are related to
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acoustic waveguides configured to be coupled to one or more selected high-frequency
speaker drivers and that include sound channels configured to direct the sound waves
produced by the speaker drivers through the sound channels and out of a front, distal
end of the acoustic waveguide. Specific details of the present technology are described
herein with respect to Figures 1-8. Although many of the embodiments are described
with respect to acoustic waveguides, it should be noted that other applications and
embodiments in addition to those disclosed herein are within the scope of the present
technology. Further, embodiments of the present technology can have different
configurations, components, and/or procedures than those shown or described herein.
Moreover, a person of ordinary skill in the art will understand that embodiments of the
present technology can have configurations, components, and/or procedures in addition
to those shown or described herein and that these and other embodiments can be
without several of the configurations, components, and/or procedures shown or
described herein without deviating from the present technology.
[0016] Figures 1-4 illustrate an acoustic waveguide 1 00 in accordance with
embodiments of the present technology. The waveguide 1 00 of the illustrated
embodiment is configured to receive a speaker driver 101 (Figure 3), such as a highfrequency
compression driver, which is coupled to a source signal generator ("SSG")
that provides electrical signals to the driver 1 01. The driver 1 01 generates acoustic
sound waves having selected frequencies. The waveguide 1 00 of the illustrated
embodiment is configured for use with a high-frequency driver that generates highfrequency
sound waves with a frequency in the range of approximately 500Hz to 20kHz.
Other embodiments can be configured for use with a midrange driver or other driver
that generates sound waves within a different range of frequencies. The waveguide
1 00 of the illustrated embodiment is configured to direct the sound received from the
driver 1 01 through the waveguide 1 00 to a plurality of outlet apertures 126a-h, such that
the sound is distributed across multiple sound paths and exits the outlet apertures 126ah
at the distal end 182 of the waveguide 1 00 in selected directions and with a coherent
wavefront for a desired range of sound distribution from the waveguide 1 00. This
configuration can allow multiple waveguides to be arrayed together to produce a
substantially cylindrically shaped wavefront across the array, thereby allowing the
emanating sound to project further.
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[0017] The illustrated waveguide 1 00 includes a housing 1 03 having upper and
lower housing portions 1 02 and 1 04 that can be coupled to a driver 1 01. In some
embodiments, the housing portions 1 02 and 1 04 are mirror symmetrical about the
mating plane of each housing portion 1 02 and 1 04 (such as the plane of the cross
section of Figure 4, where shown in Figures 1 and 3) and may be assembled together
in a multi-piece configuration, which may include a clamshell arrangement using one or
more mounting holes 128. A proximal portion 1 08 of the waveguide 1 00 has a proximal
mounting flange 114 configured to securely receive the driver 1 01. In the illustrated
embodiment, the mounting flange 114 has one or more mounting holes 118 that receive
fasteners to affix the driver 1 01 to the mounting flange 114 with the output of the driver
axially aligned with the mounting flange 114. Upon activation of the driver 1 01, the highfrequency
sound output is directed into an inlet aperture 116 in the mounting flange 114
and through the housing 103 along a plurality of separate, isolated, arcuate sound
channels 120a-h connected to the inlet aperture 116.
[0018] As best seen in Figure 4, the sound channels 120a-h extend through the
waveguide 100 and terminate at a plurality of adjacent outlet apertures 126a-h
positioned at the distal end 182 of the housing 103. In the illustrated embodiment, a
distal mounting flange 11 0 is provided at the distal end 182 of the housing 1 03 generally
adjacent to the outlet apertures 126a-h. The distal mounting flange 11 0 may be
configured to be affixed to a speaker assembly (not shown) to hold the waveguide 1 00
and the associated driver 101 in a selected position on or in the speaker assembly. In
some embodiments, the distal mounting flange 11 0 can be used to secure the
waveguide 100 to a horn at a selected alignment in the speaker assembly. In some
configurations the waveguide 1 00 may be an integral portion of a speaker assembly,
such that the housing 1 03 does not include a distal mounting flange. For example, the
distal portion of the waveguide will be built directly into the baffle of a speaker assembly.
[0019] As shown in Figure 3, the driver 1 01 is affixed to the proximal mounting
flange 114 and is oriented relative to the housing 103 such that a front face of the driver
101 (i.e., the portion of the driver 101 from which the high-frequency sound is emitted)
is axially aligned with the inlet aperture 116. The front face of the driver 1 01 of the
illustrated embodiment is substantially parallel with the proximal mounting flange 114
and generally normal to the top and/or bottom surface 184 and 186 of the housing 1 03
near the mounting flange. In other embodiments, the front face of the driver 101 and/or
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the mounting flange 114 can be oriented at another selected angle relative to the
housing 1 03 or to the inlet aperture 116. In such mounting configurations, the driver
1 01 may be in a skewed orientation relative to the housing generally adjacent to the
inlet aperture 116. In some embodiments, the front face of the driver can be at an angle
in the range of approximately oo - 90° relative to the distal face of the housing and the
outlet apertures 126a-h.
[0020] As seen in Figure 4, the inlet aperture 116 in the proximal mounting flange
114 is acoustically coupled to a plurality of spaced-apart sound channels 120a-h
extending through the housing 1 03. The sound channels 120 a-h are configured to
divide sound from the driver 101 and simultaneously directed their respective portions
of the sound out of the waveguide 1 00 through the adjacent distal outlet apertures 126ah
in the coherent wavefront.
[0021] In the illustrated embodiment, the housing portions 102 and 104 are
configured to define eight sound channels 120a-h defining a path through the housing
1 03. In other embodiments, the housing 1 03 can have more or less than eight sound
channels 120a-h, depending upon the desired configuration of the waveguide 1 00. In
some embodiments, the sound channels 120a-h are configured so the ratio of the depth
D of the waveguide 100 to the total width 108 of the outlet apertures 126a-h is in the
range of about 1 :1.2 to 1 :2. In some embodiments the ratio is in the range of about
1 :1.4 to 1 :1.8. In the embodiment illustrated in Figures 1-4, the ratio of the depth D to
the total width 108 is about 1 :1.44. In the embodiment illustrated in Figures 5-8,
discussed in greater detail below, the ratio of the waveguide's depth D to the total width
of the outlet apertures is about 1 :1 . 73.
[0022] Referring again to Figure 4, the sound channels 120a-h partially define a
plurality of sound paths 122a-h and are each coupled to the driver 101 and a respective
one of the spaced-apart outlet apertures 126a-h at the distal end 182 of the housing
103. The high-frequency sound waves travel from the driver 101 through the housing
1 03 along the sound paths 122a-h via the plurality of sound channels 120a-h and exit
the housing 1 03 in selected directions though the outlet apertures 126a-h. In some
embodiments, the sound paths 122a-h have a geometry configured to crossover
between frequencies in the range of about 500Hz to 2kHz.
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[0023] As shown in Figure 4, the sound channels 120a-h of the illustrated
embodiment are curved and configured so the sound paths 122a-h have substantially
equal lengths (e.g., equal acoustic lengths), such that all of the high-frequency sound
waves simultaneously entering the inlet aperture 116 from the driver 1 01 will exit the
respective outlet apertures 126a-h substantially simultaneously to produce the coherent
wave front. At least some of the sound channels 120a-h in the waveguide 1 00 of the
illustrated embodiment define a curved path with bends that exceed 180 degrees, which
allows for elongated sound paths within the housing 103 while maintaining a minimum
depth D of the housing, and while still maintaining the integrity of the sound waves
moving through the arcuate sound paths. The sound channels 120a-h can be sized
and shaped such that the sum of the cross-sectional area for each of the sound
channels 120a-h at points near the inlet aperture 116 is substantially equal to the
surface area of the output surface of the driver 1 01.
[0024] After the sound waves from the driver enter the inlet aperture 116, the
sound waves divide between inlet sound channels 117a and 117b, divide again
between secondary sound channels 121 ab, 121 cd, 121 ef, and 121 gh, and finally divide
into the sound channels 120a-h. The sound waves entering the waveguide 1 00 travel
the same distance as each of the other sound waves in the other sound channels 120ah
and reach the outlet apertures 126a-h at the distal end 182 at substantially the same
time. Based on the configuration of the inlet sound channels 117a and 117b, the
secondary sound channels 121 ab, 121 cd, 121 ef, and 121 gh, and the sound channels
120a-h, each of the high-frequency sound signals entering the waveguide 1 00 at the
same time will also exit the outlet apertures 126a-h at the same time, even though they
each pass through different inlet sound channels 117a and 117b, secondary sound
channels 121 ab, 121 cd, 121 ef, and 121 gh, and travel in different directions. In other
embodiments, the individual sound channels 120a-h can be sized such that some or all
of the corresponding sound paths 122a-h have different lengths. In some embodiments,
the sound paths 122a-h have an acoustic length of between about 120% and 200% of
the depth D (see Figure 3) of the waveguide 1 00. In other embodiments, the sound
paths 122a-h have an acoustic length of between about 130% and 145% of the depth
D of the waveguide 100. In yet other embodiments, the sound paths 122a-h have an
acoustic length of between about 138% and 141% of the depth D of the waveguide 1 00.
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In further embodiments, the sound paths 122a-h have an acoustic length of about
13g.6% of the depth D of the waveguide 1 00.
[0025] The secondary sound channels 121 ab, 121 cd, 121 ef, and 121 gh impart an
initial arcuate bend to the sound paths 122a-h after the sound waves exit the inlet sound
channels 117a and 117b. The initial arcuate bend directs the sound paths 112a-h
laterally from a direction substantially perpendicular to the mounting flange 114. In this
regard, the secondary sound channels 121 ab, 121 cd, 121 ef, and 121 gh change the
direction of the sound waves by about 70° to about goo from the direction at the inlet
aperture 116. After the sound waves exit the secondary sound channels 121 ab, 121 cd,
121 ef, and 121 gh, the sound waves are divided into the sound channels 120a-h, which
are each configured with various arcuate bends starting downstream of the secondary
sound channels 121 ab, 121 cd, 121 ef, and 121 gh near the proximal end 180 of the
housing portions 1 02 and 1 04. The bends in the sound channels 120a-h may be
substantially smooth (i.e., not abrupt) as to not adversely interact with the sound waves
traveling through the sound channels 120a-h. In some embodiments the radius of
curvature of the bends in the sound channels 120a-h is equal to or greater than double
the width of the sound channel.
[0026] In some embodiments, each of the sound channels 120a-h has a different
arcuate bend based on the position of an outlet of the secondary sound channels 121 ab,
121 cd, 121 ef, and 121 gh and the outlet apertures 126a-h of each of the sound paths
122a-h. The waveguide 1 00 is generally mirror symmetrical about a plane parallel to
the view in Figure 3 centered at the central axis of the inlet aperture 116. Accordingly,
each opposing pair of sound channels 120a-h will have mirror symmetrical geometry
about the mirror symmetrical plane (e.g., 120a and 120h, 120b, and 120g, etc.). For
example, in one embodiment, the sound channels 120a and 120h are bent opposite
each other by an angle between about 70° and goo, which creates an arcuate portion
of the sound paths 122a and 122h. The sound channels 120b and 120g are bent
opposite to each other by an angle between about 11 oo and 140°, which creates an
arcuate portion of the sound paths 122b and 122g; the sound channels 120c and 120f
are bent opposite to each other by an angle between about 170° and 200°, which
creates an arcuate portion of the sound paths 122c and 122f; and the sound channels
120d and 120e are bent opposite to each other by an angle between about 240° and
280°, which creates an arcuate portion of the sound paths 122d and 122e. Each bend
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in the illustrated embodiment has a bend radius in the range of about 0.25 inches to 0.8
inches. In each of the sound paths 122b-g, another bend following the initial bend in
the sound channels 120b-g again changes the direction of the sound paths 122b-g to
align the paths substantially parallel to the direction the sound waves travel when
entering the inlet aperture 116 to align with the direction in which the sound is output
from the waveguide 1 00. However, in other embodiments, any number of bends can
be added to the sound channels 120a-h to change the direction of the sound paths
122a-h while maintaining the desired acoustic lengths of the sound paths.
[0027] In the illustrated embodiment shown in Figures 1-4, the sound channels
120a-h have a flared configuration along all or portions of the sound channels 120a-h.
For example, in some embodiments, the sound channels 120a-h continuously flare
laterally and/or vertically outwards along the entire length of the sound channels 120ah
within or downstream of the bend areas discussed above. In other embodiments, the
sound channels 120a-h only flare out at portions near the distal end 182 of the housing
portions 102 and 104. In general, the sound channels 120a-h can have any suitable
flaring configuration, and one or both of the flares may continue until the sound waves
reach the outlet apertures 126a-h. In some embodiments, the flares along the distal
portions of the sound channels 120a-h are maintained relatively as straight as possible,
while the channel lengths are equalized by the bends in the sound channels 120a-h
closer to the proximal end portions of the sound channels. Accordingly, the bends in
the sound channels 120a-h are configured to maximize the length of the portion of the
sound channels 120a-h having the lateral and vertical flares. These longer flared
portions allow for the sidewalls of each flare to have lower flare angles (i.e., closer to
parallel side walls). This will allow the sound waves to exit the outlet apertures 126a-h
in a more planar, uniform wave configuration. This arrangement improves the
summation of the waves at the exit of the waveguide 1 00. The properly shaped flared
portions also aid in extending the low-frequency cutoff of the acoustic device.
[0028] The flaring of the one or more of the sound channels 120a-h can be
achieved by a change in width of the sound channel along some or all of the sound
channel, or by a change in height of the sound channel along some or all of the sound
channel, or by a change in both the width and height of the sound channel along some
or all of the sound channel. The lateral flare of the sound channels 120a-h includes
lateral flare surfaces 132a-h and 134a-h, respectively, and creates a single, laterally
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united wavefront, as will be explained in greater detail below. The lateral flare surfaces
of adjacent sound channels terminate at a peak, e.g., the lateral flare surface 132a and
the lateral flare surface 134b terminate at a peak 124ab, the lateral flare surfaces 132b
and 134c terminate at a peak 124bc, etc.
[0029] To ensure the sound waves spread laterally and combine sufficiently to
form a united wavefront, the sound channels 120a-h (and 220a-f, and 250a-f for an
acoustic waveguide 200, described below) may begin to flare in the lateral direction
before reaching the distal end 182 (e.g., as shown in Figure 4). With such a
configuration, the high-frequency sound waves can start to spread out before reaching
the distal end 182 to merge into a single wavefront in a shorter distance after exiting the
outlet apertures 126a-h (and 226a-f, and 256a-f for the acoustic waveguide 200). In
some embodiments, extensions (not shown) may be positioned distal to the outlet
apertures to further direct the sound waves exiting the sound paths.
[0030] The lateral flare surfaces 132a-h and 134a-h gradually flare and define a
flare angle 146a-h at the distal portions of the sound channels 120a-h that can be
between about 5° and 25°, and more preferably in the range of about 10° and 20°. In
other embodiments, the lateral flare surfaces 132a-h and 134a-h have a flare angle
146a-h at the distal portions of the sound channels 120a-h between about 12° and 18°.
In further embodiments, the lateral flare surfaces 132a-h and 134a-h may have a flare
angle 146a-h at the distal portions of the sound channels 120a-h between about 14°and
16°. The width of each outlet aperture 126a-h in the lateral direction can comprise
between about 7% and 14% of the overall width 1 08 of the waveguide 1 00. In the
illustrated embodiment, the width of each outlet aperture 126a-h in the lateral direction
can comprise is about 8.33% of the overall width 108 of the waveguide 100. In other
embodiments having between 12 and 8 sound channels, the width of each outlet
aperture 126a-h in the lateral direction comprises between about 8% and 13% of the
overall width 1 08 of the waveguide 1 00. Other embodiments having greater or fewer
sound channels changes can have outlet apertures 126a-h with other widths in the
lateral direction comprises relative to the overall width 1 08 of the waveguide 1 00.
[0031] It is noted that the sound channels 120 A- H have pipe resonance, were in
the frequency of the pipe resonance depends on the length of the sound channel 120
A- H. The depth of the lateral flare surface is 132 A- H and 134A- H is determined by
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the overall depth D of the waveguide 1 00, and the depth of the flares generally controls
how low in frequency the waveguide 1 00 can play. Accordingly, the dimensions of the
sound channels 120 A- H, including the lengths of the portions of the sound channels ,
and the depth of the flares, are selected so that at least one of the pipe resonance
frequency of the sound channel 120 A- H coincides with the low end of the waveguide
designed frequency spectrum. As a result, the waveguide 1 00 is provided with a
sensitivity boost at about the crossover frequency, which coupled with the sensitivity
boost from the flared section, provides enhanced performance of the waveguide at and
around the crossover frequency.
[0032] In embodiments with lateral flares, generally having lateral flare surfaces
132a-h and 134a-h, the depth of the flared portions of the sound channels 120a-h is
between about 80% and 87% of the depth D of the waveguide 1 00, and/or the lateral
flared portions of the sound channels 120a-h comprise between about 57% and 73% of
the overall length of the sound paths 122a-h. In other embodiments, the depth of the
flared portion of the sound channels 120a-h is between about 83% and 87% of the
depth D of the waveguide 1 00, and/or lateral flared portions of the sound channels
120a-h comprise between about 60% and 64% of the overall length of the sound paths
122a-h. In at least one embodiment, the depth of the flared portion of the sound
channels 120a-h is between about 84% and 86% of the depth D of the waveguide 1 00,
and/or lateral flared portions of the sound channels 120a-h comprise between about
61% and 63% of the overall length of the sound paths 122a-h. In further embodiments,
the depth of the flared portion of the sound channels 120a-h is greater than about 82%
of the depth D of the waveguide 1 00, and/or the lateral flared portions of the sound
channels 120a-h comprise about 65% of the overall length of the sound paths 122a-h.
The lateral flare surfaces 132a-h and 134a-h may be defined by a conic shape having
a fixed length, rho value, exit angle, entrance width, and exit width. In another
embodiment with the sound channels 120a-h having different resonance frequencies
than the above-referenced embodiment, the length of the sound channels 120a-h can
be longer or have different lengths while having the lateral flare surface is 132a-h and
134a-h forming a percentage of the depth D of the waveguide 100. For example, the
depth of the flared portion of the sound channels 1 OOa-h can be in the range of
approximately 55%-65%, or more specifically in the range of approximately 58%-62%,
or more specifically, in the range of approximately 59%-61%, and even more specifically
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in the range of 59.62%-60.98%. In yet another embodiment wherein the sound
channels 120a-h have different resonance frequencies than the above embodiments,
the depth of the flared portion of the sound channels 120a-h can be in the range of
approximately 49%- 69%, or more specifically in the range of approximately 52% -66%,
or more specifically, in the range of approximately 54%- 64%, and even more
specifically in the range of 54.67%- 63.63%.
[0033] The vertical flare of the sound channels 120a-h includes vertical flare
surfaces 136a-h and 138a-h, respectively, and creates radiation of the sound waves, to
spread the sound waves vertically, such as the sound wave radiation from a horn, and
to produce a substantially constant angle of radiation across a wide range of
frequencies. In embodiments with vertical flares, generally having vertical flare surfaces
136a-h and 138a-h, the vertical flared portions of the sound channels 120a-h comprise
between about 20% and 30% of the overall length of the sound paths 122a-h. In other
embodiments, the vertical flared portions of the sound channels 120a-h comprise
between about 23% and 27% of the overall length of the sound paths 122a-h. In further
embodiments, the vertical flared portions of the sound channels 120a-h comprise about
25% of the overall length of the sound paths 122a-h. The vertical flare surfaces 136ah
and 138a-h may be defined by a dual conic shape having a first portion with a fixed
length, rho value, exit angle, and exit width, and a second portion with a fixed length,
rho value, exit angle, and exit width. The vertical flare surfaces 136a-h and 138a-h may
be defined by other configurations, such as a conic-arc-conic configuration, or an arcarc-
conic configuration.
[0034] In some embodiments, the vertical flare surfaces 136a-h and 138a-h are
configured to provide an acoustic dispersion pattern having an angle in the range of
about 30°-130°. In the embodiment illustrated in Figures 1-4, the acoustic dispersion
pattern has an angle of approximately 1 05° from the distal end 182 along the vertical
direction, and in the embodiment illustrated in Figures 5 - 8, the acoustic dispersion
pattern has an angle of about 90°. In the coupling direction, the flares are brought to
the outer surface of the waveguide 1 00 so the flares can be as long as possible, even
though the perpendicular horn flare begins to shape the wave in that direction before
the flare is complete. This improves low-frequency loading and creates a more coherent
line source in the coupling direction. Figures 9A and 98 show exemplary profiles in the
lateral (Figure 9A) and vertical (Figure 98) directions in a schematic representation.
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The profiles are shown with straightened sound paths for sake of clarity and illustration
purposes only. These examples show dimensional detail of one representative
configuration of the lateral and vertical flares in the sound channels 120a-h, which may
define arcuate sound channels.
[0035] The flared shape described herein can be expected to maximize the
efficiency with which sound waves traveling through the sound channels 120a-h are
transferred into the air outside of the housing portions 1 02 and 1 04. The flaring may
also help damp pipe resonances that may exist within the sound channels 120a-h, such
as by adding an exponential curve to the flared surfaces. In other embodiments,
however, the sound channels 120a-h may not have a flared configuration, or the amount
of flaring occurring in some or all of the sound channels may be different. In other
embodiments, the sound channels 120a-h can be further divided, such as by providing
shaped inserts or dividing structures (not shown) that split the sound channels 120a-h
into two or more subchannels, each of which has the same overall sound path length
as the other sound channels 120a-h.
[0036] Adjustments to the dimensions of the sound channel can also be achieved
by controlling the channel height along some or all of the length of the channel. For
example, Figure 3 shows a side elevation view of a housing portions 1 02 and 1 04 of
the waveguide 1 00. The housing portions 1 02 and 1 04 includes a rear mounting flange
114. During operation of the waveguide 1 00, a high-frequency driver coupled to the
rear mounting flange 114 can generate high-frequency sound waves that enter the
housing portions 1 02 and 1 04 by passing through the inlet aperture 116. Upon entering
the housing portions 1 02 and 1 04, the high-frequency sound waves are directed into
the sound channels 120a-h through inlet sound channel 117a and 117b, and through
secondary sound channels 121 ab, 121 cd, 121 ef, and 121 gh. The sound channels
120a-h are configured to direct the sound waves toward the distal end 182 of the
housing portions 102 and 104.
[0037] In this illustrated embodiment, each sound channel 120a-h can flare
vertically as it approaches the distal end 182 of the housing portions 102 and 104, such
that the channel has a first height H1 (Figure 3) at a point near the inlet aperture 116
and a second height H2 that is greater than the first height H 1. In some embodiments,
all of the sound channels 120a-h increase in height as they extend toward the distal end
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182. In the illustrated embodiment, the distal end 182 of the waveguide 1 00 at the outlet
apertures 126a-h is configured with an arcuate distal end 182 (Figure 4) when viewed
from a plan orientation. In some embodiments, the arcuate distal end 182 has a radius
of about 70 inches and a localized angle along the arc of between about 5.5° and 6.5°;
however, other radii and angles are within the scope of the present technology. Taking
the localized angle of the arc between about 11 o and 13°, the resulting acoustic radiation
beam is about 15° from the distal end 182. In this regard, stacking two adjacent acoustic
waveguides 1 00 results in about 30° of coverage, three adjacent acoustic waveguides
result in about 45°, etc. Other embodiments can have other flare configurations. For
example, a single waveguide can be configured with virtually no vertical flare or up to
about 30° or 40° or more.
[0038] The distal end 182 may be generally perpendicular to the longitudinal axis
of the waveguide 1 00 when viewed from the side, such as in the orientation shown in
Figure 3. The shape of the arcuate distal end 182 can produce a sound wave profile
for wider distribution. In other embodiments, the waveguide 100 can be configured with
a curved or substantially flat and/or planar distal end to further tailor the distribution of
the sound wave profiles exiting the waveguide. In further embodiments, the
waveguide's distal end can have other shapes (i.e., multi-planar, partially-circular,
partially-spherical, etc., or combinations thereof), and the distal end can be at one or
more selected angles relative to the longitudinal axis of the waveguide 1 00.
[0039] Figures 5-8 show another embodiment of an acoustic waveguide 200
configured in accordance with the present technology. Certain features of the acoustic
waveguide 200 are similar to features of the waveguide 1 00, with Figures 5-8 generally
corresponding to Figures 1-4, respectively. The similar features have like reference
numbers, except the reference number are in the 200-series for the acoustic waveguide
200, unless otherwise noted. The acoustic waveguide 200 is configured to interface
with two high-frequency compression drivers 201 laterally spaced apart from each other
and coupled to mounting surfaces 214a and 214b at a proximal end 280. The mounting
surfaces 214a and 214b may be generally positioned perpendicular to a top surface
284 of a housing portion 202, and the bottom surface 286 of a housing portion 204, and
axially aligned with inlet apertures 216a and 216b. In other embodiments the mounting
surfaces can be configured to position the drivers 201 at a selected angle relative to the
distal surface of the waveguide (i.e., in the range of about oo- 90°). While the illustrated
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embodiment is shown with two compression drivers 201, other embodiments can have
other numbers of compression drivers 201 and corresponding mounting surfaces. The
housing portions 202 and 204 defining the housing 203 are similar to the housing
portions 1 02 and 1 04 of the waveguide 1 00, but has a different number of inlet
apertures, high-frequency sound channels, mounting surfaces, outlet apertures, etc., as
shown in Figures 5-8.
[0040] Among other differing aspects, the acoustic waveguide 200 differs from the
waveguide 1 00 by having separate but mirror symmetrical sound channels relative to
each high-frequency driver HFD. In this regard, a plurality of sound channels 220a-f,
extending from the inlet aperture 216a, are mirror symmetrical to a plurality of sound
channels 250a-f, extending from the inlet aperture 216b, about a centered vertical,
longitudinal plane parallel to the orientation and located equidistant between the inlet
apertures 216a and 216b. While the same mirror symmetry of the housing 203 about
the mounting surfaces is present, the mirror symmetry about the vertical, longitudinal
plane provides an increased soundstage at the outlet apertures 226a-f and 256a-f.
Unlike the waveguide 1 00, in the acoustic waveguide 200, each separate mirror
symmetrical sound channel group (e.g., 220a-f or 250a-f) is not itself mirror symmetrical
about a central axis of the respective inlet aperture 216a and 216b. For example, while
the outermost sound channels 120a and 120h of the waveguide 1 00 are mirror
symmetrical about the central axis of the inlet aperture 116, the outermost sound
channels 220a and 220f (or 250a and 250f) are not mirror symmetrical about the central
axis of the inlet aperture 216a (or 216b).
[0041] In the illustrated embodiment, each group of sound channels 220a-f and
250a-f has six channels. In other embodiments, each group has greater than four sound
channels. The acoustic waveguide 200 may also omit the inlet sound channels (i.e.,
the inlet sound channels 117a and 117b of the waveguide 1 00) and transition the sound
waves directly to secondary sound channels 221 ab, 221 cd, 221 ef, 251 ab, 251 cd, and
251 ef, among other possible configurations. The sound channels 220a-f and 250a-f
may include a fewer or greater quantity or degree of arcuate bends when compared
with the sound channels 120a-h, such as shown in Figure 8. The sound channels 220
within the waveguide can also be configured with a greater of fewer number of stages
of channel splitting or dividing for selected larger or smaller compression drivers.
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[0042] The acoustic waveguide 200 includes two sets of high-frequency sound
channels 220a-f and 250a-f, each coupled a respective one of the two drivers 201. As
described above with respect to the waveguide 1 00, the sound channels 220a-f and
250a-f terminate at outlet apertures 226a-f and 256a-f in the distal end 282 of the
housing 203. In the illustrated embodiment, a distal mounting flange 21 0 is provided at
the distal end 282 of the housing 203 generally adjacent to the outlet apertures 226a-f
and 256a-f. The distal mounting flange 210 may be configured to be affixed to a speaker
housing (not shown) to hold the acoustic waveguide 200 and the associated high-range
drivers 201 in position in the speaker housing. In some embodiments, the mounting
flange 210 can be used to couple the acoustic waveguide 200 to a horn (not shown),
such as a horn attached to the speaker housing.
[0043] In some embodiments, the lateral flare surfaces 232a-f, 234a-f, 262a-f, and
264a-f may have flare angles 246a-f and 286a-f between about 1 oo and 20°. In other
embodiments, the lateral flare surfaces 232a-f, 234a-f, 262a-f, and 264a-f may have
flare angles 246a-f and 286a-f between about 14° and 18°. In further embodiments,
the lateral flare surfaces 232a-f, 234a-f, 262a-f, and 264a-f may have flare angles 246af
and 286a-f of about 16°. The width of each outlet aperture 226a-f and 256a-f in the
lateral direction can comprise between about 7% and 14% of the overall width 209 of
the acoustic waveguide 200. In other embodiments, the width of each outlet aperture
226a-f and 256a-f in the lateral direction comprises between about 8% and 13% of the
overall width 209 of the acoustic waveguide 200.
[0044] In embodiments with lateral flares, generally having lateral flare surfaces
232a-f, 234a-f, 262a-f, and 264a-f, the depth of the flared portions of the sound channels
220a-f and 250a-f is between about 80% and 87% of the depth D of the acoustic
waveguide 200, and/or the lateral flared portions of the sound channels 220a-f and
250a-f comprise between about 57% and 73% of the overall length of the sound paths
222a-f and 252a-f. In other embodiments, the depth of the flared portion of the sound
channels 220a-f and 250a-f is between about 83% and 85% of the depth D of the
acoustic waveguide 200, and/or lateral flared portions of the sound channels 220a-f and
250a-f comprise between about 62% and 68% of the overall length of the sound paths
222a-f and 252a-f. In further embodiments, the depth of the flared portion of the sound
channels 220a-f and 250a-f is greater than about 82% of the depth D of the acoustic
waveguide 200, and/or the lateral flared portions of the sound channels 220a-f and

CLAIMS
We claim:
1. An acoustic waveguide, comprising:
a housing having a proximal end with an inlet aperture and a distal end with an
outlet aperture;
a mounting flange positioned at the proximal end and configured to acoustically
couple a driver to inlet aperture; and
a plurality of sound channels extending through the housing and acoustically
coupling the inlet aperture to the outlet aperture, each sound channel at least partially
defining a sound path having an acoustic length, wherein at least one of the sound paths
of the plurality of sound channels has a bend angle that exceeds 180 degrees.
2. The acoustic waveguide of claim 1 wherein the driver is a high-frequency
driver with an output frequency greater than 500Hz.
3. The acoustic waveguide of claim 1 wherein the acoustic length of each
sound path of the plurality of sound channels is substantially equal to each of the other
sound paths.
4. The acoustic waveguide of claim 1, further comprising a plurality of inlet
sound channels positioned between and acoustically coupling the inlet aperture and the
plurality of sound channels, wherein the inlet sound channels divide the inlet aperture
into at least two sound paths.
5. The acoustic waveguide of claim 4 wherein the plurality of sound channels
comprises primary sound channels, wherein the acoustic waveguide further comprises
a plurality of secondary sound channels positioned between and acoustically coupling
the inlet sound channels and the primary sound channels, and wherein the secondary
sound channels divide each of the inlet sound channels into at least two sound paths.
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6. The acoustic waveguide of claim 5 wherein each of the secondary sound
channels changes a direction of the corresponding sound path in the range of about 70°
to 90° from a direction perpendicular to the mounting flange.
7. The acoustic waveguide of claim 5 wherein the plurality of primary sound
channels divide each of the secondary sound channels into at least two sound paths.
8. The acoustic waveguide of claim 1 wherein the at least one of the sound
paths of the plurality of primary sound channels has a bend radius in the range of about
0.25 inches to 0.8 inches.
9. The acoustic waveguide of claim 1 wherein the outlet aperture is
partitioned such that each of the plurality of sound channels is acoustically coupled to
an individual portion of the outlet aperture.
10. The acoustic waveguide of claim 1 wherein the acoustic waveguide is
mirror symmetric about a plane perpendicular to a surface of the mounting flange
bisecting the inlet aperture, and wherein the plane is positioned vertically such that a
vector across the width of the acoustic waveguide is normal to the plane.
11. The acoustic waveguide of claim 1 wherein the primary sound channels
flare laterally and/or vertically outwards to the distal end along at least a portion of the
primary sound channels downstream of a bend area, and wherein the lateral flares of
the primary sound channels define a flare angle at distal portions of the primary sound
channels between about 1 oo and 20°, between about 12° and 18°, or between about
14°and16° ..
12. The acoustic waveguide of claim 1 wherein each sound path is an arcuate
path defined by at least one bend having a radius of curvature and having a path width
at the at least one bend, wherein the radius of curvature is equal to or greater than
double the path width at the bend.
13. An acoustic waveguide, comprising:
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a housing having a proximal end with a first inlet aperture and a second inlet
aperture and a distal end with a first outlet aperture and a second outlet aperture;
a first mounting flange positioned at the proximal end and configured to
acoustically couple a first driver to the first inlet aperture;
a second mounting flange positioned at the proximal end and configured to
acoustically couple a second driver to the second inlet aperture;
a plurality of first sound channels extending through the housing and acoustically
coupling the first inlet aperture to the first outlet aperture; and
a plurality of second sound channels extending through the housing and
acoustically coupling the second inlet aperture to the second outlet aperture,
wherein each of the plurality of the first and second sound channels at least
partially defines a sound path having an acoustic length substantially equal to each of
the other sound paths; and
wherein at least one of the sound paths of the plurality of first sound channels
has a bend angle that exceeds 180 degrees.
14. The acoustic waveguide of claim 13 wherein at least one of the sound
paths of the plurality of second sound channels has a bend angle that exceeds 180
degrees.
15. The acoustic waveguide of claim 13, further comprising a plurality of first
inlet sound channels positioned between and acoustically coupling the first inlet
aperture and the plurality of first sound channels, wherein the first inlet sound channels
divide the first inlet aperture into at least two sound paths.
16. The acoustic waveguide of claim 13, further comprising a plurality of
second inlet sound channels positioned between and acoustically coupling the second
inlet aperture and the plurality of second sound channels, wherein the second inlet
sound channels divide the second inlet aperture into at least two sound paths.
17. The acoustic waveguide of claim 13 wherein at least one of the first and
second inlet sound channels changes a direction of the corresponding sound path in
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the range of about 70° to 90° from a direction perpendicular to the corresponding first
or second mounting flange.
18. The acoustic waveguide of claims 13 wherein a ratio of a depth of the
housing to a width of the outlet aperture is in the range of about 1 :1.2 to 1 :2, in the range
of about 1:1.4 to 1 :1.8, is about 1:1.44, or is about 1:1.73.
19. The acoustic waveguide of claims 13 wherein the acoustic length of the
sound channels is between about 120% and 200% of the depth of the housing, between
about 130% and 145% of the depth of the housing, between about 138% and 141% of
the depth of the housing, about 139.6% of the depth of the housing, or about 136.7% of
the depth of the housing.
20. The acoustic waveguide of claim 13, further comprising at least one
compression driver connected to the mounting flange and configured to generate and
direct sound into the inlet aperture.