Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
LOUDSPEAKER ENCLOSURE
FIELD OF INVENTION
[0001]. The present invention relates to loudspeaker enclosures, and in
particularly, to a
speaker enclosure for reducing standing waves and cabinet resonance.
BACKGROUND OF THE INVENTION
[0002]. Many different types of loudspeaker enclosures have been developed for
the purpose
of reproducing sound. The types of loudspeaker enclosures/cabinets that have
been
primarily used in sound reproduction include bass reflex, acoustic suspension,
horn
cabinets, and transmission line.
[0003]. Bass Reflex (Tuned Port /Thiel Ported) - The bass reflex cabinet
design is a common,
widely accepted cabinet design used currently. The bass reflex design uses a
resonating tube mounted inside an opening/hole in the cabinet, to provide low
frequency extension (amplification of low frequency sound waves) and emit
those
sound waves from the cabinet. Although the Bass Reflex cabinet design provides
low
frequency extension, it does so inefficiently by sound waves reflecting inside
the
cabinet between hard surfaces making their way to the port in a haphazard
fashion.
These cabinets are stuffed with fibrous dampening materials to absorb standing
waves
and internal sound waves that are not emitted from the port.
[0004]. Acoustic Suspension (Infinite Baffle) - The acoustic suspension
cabinet design is a
totally sealed enclosure. The internal pressure of the fixed air volume in the
cabinet
cavity acts like a shock absorber to restrict the movement of the low
frequency driver
cone, which restricts the generation of low frequency sound waves inside the
cabinet.
The theoretical basis of the acoustic suspension cabinet is that a
sufficiently large
sealed cabinet provides results similar to an infinite baffle. An infinite
baffle design has
drivers mounted on a flat baffle of theoretical infinite width and height,
eliminating anti-
phase sound wave radiation caused from sound waves that are longer than the
size of
the baffle. Although the acoustic suspension design offers an interesting
theoretical
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Date Recue/Date Received 2022-12-29
design focussed on eliminating anti-phase sound wave radiation, fewer
loudspeaker
cabinet manufacturers use this design.
[0005]. Horn Cabinets - Horn cabinet designs date back to the 17th century,
originating in early
versions of megaphones used to amplify voices in large gatherings. Very
efficient at
amplifying sound waves, the convex horn shape directs sound waves from a
source in
a relatively narrow dispersion pattern forward of the horn. The drivers are
mounted on
horns that are integrated into the cabinet design, however, the sealed or
ported
cabinets that enclose the driver have the same limitations as other designs.
Although
loud (efficient), the musical quality of horn designs is often not flat over
the normal
audible frequency range of music (20 hertz to 20,000 hertz)
[0006]. Transmission Line - A transmission line cabinet design is constructed
to reflect the low
frequency sound waves generated inside the cabinet through a series of
internal
chambers, with each progressive chamber reducing in size from the previous,
using
intricately cut angled members to reflect the sound waves through the chambers
and
out of an opening/hole in the cabinet. Although transmission line cabinets
systematically emit low frequency sound waves from the cabinet more
efficiently than
bass reflex designs, they normally have parallel internal walls that generate
standing
waves. In each chamber, fibrous batting is used to dampen standing waves and
other
reflected waves that are not directed into the next chamber. The transmission
line
cabinet design primarily focusses on low frequency bass extension
(amplification) and
does not provide emission of mid-range frequency sound waves generated inside
the
cabinet. Typical transmission line cabinets have a very large number of
precision cut
pieces making up the internal chambers, and therefore are difficult and costly
to
manufacture with any degree of precision.
[0007]. Wavelengths of low frequency sounds are very long as shown below as a
point of
reference and consideration of how they may react when trapped inside a
typical
rectangular box enclosure:
a. Hertz Wavelength (Meters)
b. 20 17.4
c. 30 11.6
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Date Recue/Date Received 2022-12-29
d. 40 8.6
e. 60 5.8
[0008]. In all of the types of loudspeaker cabinets listed above, there are
three fundamental
problems with the quality of sound waves reproduced with the cabinets (due to
the
internal shape of the cabinet being flat, primarily made from wood fiber based
materials, stuffed with fibrous sound dampening material), which are:
[0009]. Standing Waves ¨Sound waves that reflect back and forth between
parallel surfaces
inside a loudspeaker cabinet. Standing waves create unpleasant and distorted
sound
waves that are transmitted through the cabinet material to the air surrounding
the
cabinet.
[0010]. Cabinet Resonance ¨ Similar to standing waves, sound waves that
reflect within the
cabinet, not necessarily off parallel walls, transmit through the cabinet
material to the
air outside the cabinet creating an unpleasant cabinet resonance that is
audible.
[0011]. Driver Distortion ¨ Sound waves that reflect within the cabinet,
striking the drivers that
are at that time trying to produce a different sound wave creates driver
distortion (or
sound elimination if the wave is directly inverse) effecting the clarity of
the sound being
reproduced by the driver.
[0012]. In each type of loudspeaker cabinet listed above, a large portion of
the internal volume
of the cabinet is stuffed with fibrous batting to dampen (absorb) the sound
waves that
are reflecting around inside the cabinet. The purpose of the internal batting
is to reduce
standing waves, cabinet resonance and driver distortion as described above.
Three of
the above discussed loudspeaker enclosures/cabinets have ports or openings
that are
designed to transmit low frequency sound waves out of the cabinet. The
internal
batting dampens sound waves, reducing the sound pressure level of waves
emitted
through the port or opening.
[0013]. The transmission line cabinets are designed in a manner that logically
and purposefully
directs sound waves out of the cabinet, emitting them through an opening/hole
in the
cabinet. Although the transmission line cabinet design emits sound waves, the
complex
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flat internal members used to direct the sound waves do so inefficiently, and
with the
large volumes of fibrous batting inside the cabinet only a small percentage of
the sound
waves are emitted from the cabinet. In a transmission line cabinet design, the
only
audible sound waves that are emitted from the opening in the cabinet are the
low
frequency bass sound waves.
[0014]. Accordingly, there is a need for a loudspeaker enclosure which is not
subject to one or
more limitations of the prior art.
[0015]. This background information is provided for the purpose of making
known information
believed by the applicant to be of possible relevance to the present
invention. No
admission is necessarily intended, nor should be construed, that any of the
preceding
information constitutes prior art against the present invention.
SUMMARY OF THE INVENTION
[0016]. An object of the present invention is to provide an enclosure for
loudspeaker system.
[0017]. In accordance with an aspect of the present invention, there is
provided an enclosure
for loudspeaker system comprising one or more speaker drivers. The enclosure
comprises a) a housing being formed of continuous side wall, back wall, lower
and
upper walls, and having a front planar elliptically shaped opening, the
housing defining
an internal chamber surface having a semi-ellipsoidal shape having a major
axis and a
minor axis perpendicular to the major axis, the internal chamber surface
having a semi-
elliptical cross section having a first focal point and a second focal point
along the
major axis, and a semi-circular cross section along the minor axis, and b) a
planar
baffle member configured to be positioned across the front opening of the
housing, the
baffle member having first and second sound wave emission openings dimensioned
and positioned on a vertical centre line of the baffle member, the first and
second
sound wave emission openings being positioned to be concentric with the first
and
second focal points, respectively, the baffle member further comprising one or
more
mounting openings to mount/secure the one or more speaker drivers between the
first
and the second sound wave emission openings; such that sound waves generated
by
the one or more speaker drivers inside the enclosure are reflected from the
internal
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Date Recue/Date Received 2022-12-29
chamber surface and directed to exit the housing via the sound wave emission
openings.
BRIEF DESCRIPTION OF THE FIGURES
[0018]. Further features and advantages of the present disclosure will become
apparent from
the following detailed description, taken in combination with the appended
drawings, in
which:
[0019]. Fig. 1 depicts a schematic perspective view of the loudspeaker
enclosure, in
accordance with an embodiment of the present invention.
[0020]. Fig. 2 depicts a schematic perspective view of the housing of the
enclosure, in
accordance with an embodiment of the present invention.
[0021]. Fig. 3 depicts a schematic view of the housing and the baffle member
of the enclosure
(in a disassembled form), in accordance with an embodiment of the present
invention.
[0022]. Fig. 4 depicts a cross sectional view of the enclosure and the baffle
member of the
enclosure (in an assembled form), in accordance with an embodiment of the
present
invention.
[0023]. Fig. 5 depicts a cross sectional view of the enclosure and the baffle
member of the
enclosure (in an assembled form, including a speaker driver), in accordance
with an
embodiment of the present invention.
[0024]. Fig. 6 depicts a perspective view of the housing and the baffle member
of the
enclosure (in assembled form, including a speaker drivers), in accordance with
an
embodiment of the present invention.
[0025]. Fig. 7 depicts a perspective view of the enclosure and the baffle
member of the
enclosure (in assembled form), in accordance with an embodiment of the present
invention.
Date Recue/Date Received 2022-12-29
[0026]. The specific arrangements shown in the Figures should not be viewed as
limiting. It
should be understood that the illustrated elements, including and the shape,
size and
scale, are not drawn in actual proportion to each other.
DETAILED DESCRIPTION OF THE INVENTION
[0027]. Unless defined otherwise, all technical and scientific terms used
herein have the same
meaning as commonly understood by one of ordinary skill in the art to which
this
invention belongs.
[0028]. Unless the context requires otherwise, throughout this specification
and claims, the
words "comprise", "comprising" and the like are to be construed in an open,
inclusive
sense.
[0029]. The articles "a" and "an" are used herein to refer to one or to more
than one (i.e., to at
least one) of the grammatical object of the article. By way of example, "an
element"
means one element or more than one element.
[0030]. As used herein, the term "about" refers to approximately a +1-10%
variation from a
given value. It is to be understood that such a variation is always included
in any given
value provided herein, whether or not it is specifically referred to.
[0031]. The term semi- elliptical as used herein refers to half of an ellipse
as dissected by its
centre axis as depicted below. An ellipse as defined mathematically, is a
plane curve
surrounding two focal points (shown as the egg shaped line below). The focal
points of
an ellipse are two points F1 and F2 on the ellipse's centreline along its
major axis that
are equidistant from the centre point "C". The sum of the distances from any
point P on
the ellipse to the two focal points is constant and equal to the overall
length of the
major axis (PF1 + PF2 = 2a). (2a = the distance from point -a to point a.)
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Date Recue/Date Received 2022-12-29
PEt+PF2=2a b e=fla
4P iihhii._,4411111
-a a
-b
[0032]. The present invention provides an enclosure for a loudspeaker system,
for efficiently
emitting the sound waves generated by the back of a speaker driver from inside
a
speaker enclosure to the outside, for improving the quality of sound.
[0033]. The enclosure of the present invention comprises a housing formed of a
continuous
side wall, a back wall, lower and upper walls, and provided with a front
elliptically
shaped planar opening. The housing defines an internal chamber surface having
a
semi-ellipsoidal shape having a major axis and a minor axis perpendicular to
the major
axis. The internal chamber surface has a semi-elliptical cross section having
a first
focal point and a second focal point along the major axis, and a semi-circular
cross
section along the minor axis.
[0034]. The enclosure further comprises a planar baffle member configured to
be positioned
across the front opening of the housing. The baffle member has first and
second
sound wave emission openings appropriately dimensioned and positioned on a
vertical
centre line of the baffle member. The first and second sound wave emission
openings
are positioned to be concentric with the first and second focal points,
respectively. The
baffle member further comprises one or more mounting openings to mount/secure
the
one or more speaker drivers between the first and the second sound wave
emission
openings, such that sound waves generated by the one or more speaker drivers
inside
the enclosure are reflected by the internal chamber surface and directed to
exit the
housing via the sound wave emission openings.
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Date Recue/Date Received 2022-12-29
[0035]. The baffle member is further configured to secure electrical
connections and/or
crossover network of the loudspeaker system.
[0036]. In some embodiments, the enclosure further comprises appropriately
dimensioned
resonating tube extending outwardly from one of the sound wave emission
openings.
[0037]. In some embodiments, the major axis of the internal chamber surface is
oriented
vertically, and the first sound wave emission opening and the first focal
point is located
above the speaker driver(s) and the second sound wave emission opening and the
second focal point is located below the speaker driver(s).
[0038]. In some embodiments, a resonating tube extends outwardly from the
second (lower)
sound wave emission opening to provide low frequency sound pressure level
extension
(amplification), and the upper sound wave emission opening does not have a
resonating tube, as the purpose of the upper sound wave emission opening is to
emit
mid and bass range sound waves in a more widely dispersed pattern to enhance
sound wave dispersion and generate a more open sound stage to the listener.
[0039]. Due to the semi - ellipsoidal shape of the internal chamber surface of
the enclosure,
the sound waves being generated by the drivers on the inside of the enclosure
are
reflected and directed to exit at the focal points of the semi-ellipsoid along
the vertical
centre line of the baffle.
[0040]. In some embodiments, one of the mounting openings is configured to
receive a low
frequency speaker driver (woofer), such that the low frequency speaker driver
is
centered on the vertical centre line of the baffle member between the first
and the
second focal points to attain the desired sound pressure level emission from
both focal
points. .
[0041]. In some embodiments, the centre point of the low frequency speaker
driver coincides
with the centre point of the elliptical front opening.
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Date Recue/Date Received 2022-12-29
[0042]. In some embodiments, the centre of the low frequency speaker driver
mounting
opening coincides with the centre point of the elliptical front opening.
[0043]. In some embodiments, the low frequency speaker driver is positioned at
the horizontal
centre line of the baffle member.
[0044]. In some embodiments, the centre point of the low frequency speaker
driver is placed
on the vertical centre line of the baffle member between the lower focal point
and the
centre point of the elliptical front opening
[0045]. In some embodiments, the centre of the low frequency speaker driver
mounting
opening is placed on the vertical centre line of the baffle member between the
lower
focal point and the centre point of the elliptical front opening.
[0046]. The sound waves reproduced by the woofer are the lower frequencies
typically in the
range of 20 hertz to 600 hertz which are long sound waves that create a large
amount
of cabinet resonance and internal distortion in a typical rectangular cabinet.
Therefore,
it is desired to have these lower frequency sound waves emitted out of the
cabinet with
minimal internal reflections. The lower frequency sound waves transmitted
through the
lower sound wave emission opening through the resonating tube that extends
outside
of the enclosure provide sound pressure level extension (amplification).
[0047]. In some embodiments, one of the mounting openings is configured for
mounting a mid-
range driver directly above the low frequency driver on the centre line of the
baffle,
close to the sound wave emission opening positioned above the low frequency
driver.
The efficient emission of mid-range frequency sound waves through the upper
emission opening in a widely dispersed pattern improves what is commonly
referred to
as "sound stage".
[0048]. The dimensions of the sound emission openings and/or the resonating
tube (i.e. width,
length, wall thickness) can be determined based on the internal volume of the
enclosure, the size of the frequency driver (woofer), and desired frequency
amplification.
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Date Recue/Date Received 2022-12-29
[0049]. In some embodiments, the sound wave emission openings each have a
diameter from
about 2" to about 5".
[0050]. In some embodiments, the resonating tube has a diameter from about 2"
to about 5"
and a length from about 4" to about 10". In some embodiments, the resonating
tube
has a diameter from about 2.5" to about 3.5" and a length from about 4.5" to
about 65".
[0051]. The housing of the enclosure of the present invention is made of high
density sound
wave reflective material, such as concrete, cement, etc., to achieve a high
level of
sound wave reflection and minimize sound wave transmission through the walls
of the
housing. In some embodiments, the high density sound wave reflective material
comprises a mixture of cement and sand.
[0052]. The baffle member can be constructed from high density, high rigidity
material, which
can be cut or machined to install speaker drivers. In some embodiments, the
baffle
member is made of a high density, high rigidity material such as hard wood.
[0053]. The resonating tube can be constructed from high density, high
rigidity material which
can be cut or machined.
[0054]. Due to the specific shape of the housing and the specific positioning
of the sound
emission openings on the baffle member, the loudspeaker enclosure of the
present
invention can reduce or minimize generation of standing waves inside the
loudspeaker
enclosure, and reduce cabinet resonance by directing the sound waves out of
the
housing through the sound emission openings, leaving fewer internal sound
waves
reflecting back to hit the internal walls of the housing multiple times.
[0055]. High density moulded construction of the housing further reduces
cabinet resonance
by reducing sound wave transmission through the cabinet material to the air on
the
outside of the cabinet.
[0056]. The enclosure of the present invention can also reduce driver sound
distortion, which is
caused by sound waves being emitted from a vibrating driver (speaker cone)
striking
the inside surface of the enclosure and reflecting back towards that driver or
another
Date Recue/Date Received 2022-12-29
driver and striking the drivers at a delay. Due to the elliptical shape of the
interior
surface of the housing, more sound waves are emitted out of the enclosure
through the
emission openings, and fewer internal sound waves reflect back to hit the
drivers that
are vibrating at a different frequency to generate different sound waves at
that time.
[0057]. The enclosure of the present invention does not require the use of
fibrous materials
inside the housing to dampen the internal sound waves, as the enclosure is
configured
to emit the sound waves from the enclosure, thereby reducing the cost of
manufacturing.
[0058]. The present enclosure further improves sound stage imaging due to more
reflected
mid-range sound waves being emitted from the enclosure, rather than being
dampened
inside the enclosure.
[0059]. The placement of an appropriately sized resonating tube on the outside
of the baffle
further provides low frequency sound wave extension (amplification), which
does not
interfere with the geometric principles of the interior surface of the
enclosure, and does
not interfere with the efficient transmission of sound waves through each
emission
opening to the outside of the enclosure.
[0060]. The present enclosure provides flexibility in locating the loudspeaker
enclosure within a
listening room. Placement of the present enclosure from the side wall or rear
wall
surfaces of the housing in a listening room has no effect on sound waves
transmitted
from this enclosure since all sound waves are transmitted in a forward
direction from
the baffle. Several other loudspeaker cabinet manufacturers typically suggest
a specific
placement of the cabinet in the listening room, measured from side walls or
rear walls
to optimize the musicality of the sound produced by those loudspeakers.
[0061]. To gain a better understanding of the invention described herein, the
following
examples are set forth with reference to the accompanying drawings, which are
not
drawn to scale, and the illustrated components are not necessarily drawn
proportionately to one another. It will be understood that these examples are
intended
to describe illustrative embodiments of the invention and are not intended to
limit the
scope of the invention in any way.
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Date Recue/Date Received 2022-12-29
EXAMPLES
[0062]. Figs. 1, 3 and 4 depict an exemplary loudspeaker enclosure (10) of the
present
invention, which comprises a housing (12) and a planar baffle member (14)
(shown
without any speaker component).
[0063]. As shown in Fig. 2, the housing (12) is formed of continuous side
wall, back wall, lower
and upper walls (14a, 14b, 14c and 14d, respectively), and has a planar front
opening
(16). The housing defines an internal chamber surface (18) having a semi-
ellipsoidal
shape having a major axis (y-y') and a minor axis (x-x') perpendicular to the
major axis
(Figs. 2 and 3). The internal chamber surface has a semi-elliptical cross
section
having a first focal point (F1) and a second focal point (F2) along the major
axis, and a
semi-circular cross section along the minor axis (Figs. 4 and 5).
[0064]. The planar baffle member (14) is configured to be positioned across
the front opening
(16) of the housing (Figs. 1 and 4), and has a vertical centre line (L-L') and
a horizontal
centre line (T-T') (Fig. 3). The baffle member has a first/upper sound wave
emission
opening (20) and a second/lower sound wave emission opening (22). Both
openings
are dimensioned and positioned along the vertical centre line (L - L') of the
baffle
member. The first and second sound wave emission openings are positioned to be
concentric with the first and second focal points (F1, F2), respectively as
shown in Fig.
4. The baffle member further comprises mounting opening (24) to mount/secure a
speaker driver located between the first and the second sound wave emission
openings.
[0065]. In this example, the major axis of the internal chamber surface is
oriented vertically (y-
y'), and the first sound wave emission opening (20) and the first focal point
(F1) are
located above the speaker driver mounting opening (24) and the second sound
wave
emission opening (22) and the second focal point (F2) are located below the
speaker
driver mounting openings.
[0066]. In this example, the baffle member further comprises a resonating tube
(26) extending
outwardly from the lower sound wave emission opening.
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Date Recue/Date Received 2022-12-29
[0067]. The speaker driver mounting opening (24) is configured to receive a
low frequency
speaker driver/woofer (28), such that the centre of the mounting opening (24)
or the
centre point of the driver coincides with the centre point of the elliptically
shaped front
opening (Figs. 4 and 5).
[0068]. Alternatively, the woofer mounting opening (24) is configured, such
that the centre of
the mounting opening (24) is placed between the lower focal point and the
centre point
of the elliptically shaped front opening (Fig. 3).
[0069]. As shown in Fig. 5, due to the semi - ellipsoidal shape of the
internal chamber surface
(18) of the enclosure (10), the sound waves (30) that are being generated by
the driver
(28) on the interior surface of the enclosure are reflected from the back and
side walls
of the housing and directed to exit at or near the focal points (F1, F2) of
the semi-
ellipsoid along the vertical centre line of the baffle.
[0070]. The sound waves reproduced by the woofer are the lower frequencies
typically in the
range of 20 hertz to 600 hertz which are long sound waves that create a large
amount
of cabinet resonance and internal distortion in a typical rectangular cabinet.
The lower
frequency sound waves transmitted out from the enclosure via the lower sound
wave
emission opening (22) when passed through the resonating tube (26) that
extends
outwardly from the enclosure provide sound pressure level extension
(amplification).
[0071]. Figs. 6 and 7 depict another example of the enclosure of the present
invention, wherein
the housing (12) is same as in the example depicted in Fig. 1 to 5. In this
example, the
baffle member (14) is provided with two speaker driver mounting openings (24a,
24b),
wherein opening (24a) is configured to mount a mid-range driver (28a) directly
above
the low frequency driver (28b) on the centre line of the baffle and close to
the sound
wave emission opening (20). In this example, the baffle member further has a
high
frequency driver/tweeter (30) mounted therein, which has a sealed box
enclosure
surrounding the back of the driver.
[0072]. As depicted in Fig. 7, the baffle members of the present invention are
further
configured to secure electrical connections and/or crossover network (32) of
the
loudspeaker system.
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COMPARATIVE TESTS
[0073]. Several tests have been performed, measuring and comparing the sound
produced by
the same loudspeaker system comprising the enclosure of the present invention,
having drivers, crossover network, wiring, etc. mounted on the baffle member,
in
comparison to a typical rectangular, tuned port loudspeaker cabinet of
recommended
dimensions with non-parallel side walls (herein after referred as comparative
cabinet).
The comparative cabinet was built from high density particle board, two 3/4"
thick layers
were laminated together and the cabinet was internally braced at its third
section
heights to provide a cabinet that was very dense, thick and rigid. In
addition, the
comparative cabinet's sides were tapered in towards the back to minimize
parallel
surfaces. Music and sounds reproduced by loudspeaker systems were compared by
both measurable specifications and subjective listening tests of clarity,
quality and
musicality.
COMPARATIVE TEST RESULTS
[0074]. "Realistic" brand sound pressure level meter, from Radio Shack, was
used to measure
the decibel level of individual frequency sound waves from each loudspeaker
cabinet.
The meter was placed at the same height and distance from the centre line of
each
cabinet.
[0075]. The test results of the single frequency decibel level test indicate
that both
loudspeakers reproduced individual sound waves very closely at all frequency
levels.
This test confirmed that the drivers, crossover networks and wiring were
consistent and
that the designed internal volume of the test loudspeaker enclosure/cabinet of
the
present invention provided individual sound frequency reproduction levels
virtually the
same as the comparative speaker cabinet.
COMPARATIVE MUSIC LISTENING TEST RESULTS
[0076]. Despite the single frequency sound pressure level showing nearly
identical results, the
comparative music listening tests exhibited significant differences in the
clarity,
precision, quality and sound stage of music. Several individuals described the
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Date Recue/Date Received 2022-12-29
difference as "the difference between day and night". The test loudspeaker
enclosure/cabinet was preferred by each listener, the common preferences
documented were:
1. Improved clarity in bass and mid-range frequencies.
2. Subtle musical nuances were more noticeable such as background vocals,
soft vocal
elements, bass string reverberation.
3. Bass lines were more clearly defined, individual notes were more
distinguishable and
produced with better accuracy and clarity. Subtle bass fret sounds were
noticeable
from the test loudspeaker enclosure/cabinet that were not noticeable from the
comparative loudspeaker cabinet. Some listeners described the bass frequency
music
produced by the comparative loudspeaker cabinet as "muffled" compared to the
test
loudspeaker enclosure/cabinet.
4. Mid-range instruments and voices had a better sound stage, the sound
came from a
much wider field outside of the individual mid-range drivers, compared to the
relatively
directional mid-range produced by the comparative loudspeaker cabinet. Some
listeners described the mid-range music reproduced by the test loudspeaker
cabinet as
"more open" or "less restricted".
[0077]. The comparative listening results reflected characteristics consistent
with the design
objectives of the test loudspeaker cabinet:
a. fewer standing waves
b. less cabinet resonance
c. less driver distortion from reflected sound waves
d. increase in sound waves emitted from the cabinet
e. less damping of sound waves from internal fibrous materials
[0078]. There were no distinguishable differences noted in the high frequency
musical sounds
produced by each loudspeaker cabinet. The high frequency driver (tweeter) has
a
sealed box enclosure surrounding the back of the driver, therefore sound waves
are
only emitted from the front of the driver and are not affected by the cabinet
and if
placed at the same height on each cabinet sound indistinguishable.
[0079]. Although the invention has been described with reference to certain
specific
embodiments, various modifications thereof will be apparent to those skilled
in the art
Date Recue/Date Received 2022-12-29
without departing from the spirit and scope of the invention. All such
modifications as
would be apparent to one skilled in the art are intended to be included within
the scope
of the following claims.
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