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DESCRIPTION JPS61232185

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DESCRIPTION JPS61232185
[0001]
The present invention relates to a loudspeaker enclosure. The sound output from the prior art
loudspeaker system includes the sound produced by the vibration of the enclosure wall in
addition to the sound from the one or more loudspeaker drive units. The enclosure inevitably has
a resonant frequency, and the intensity of the sound produced by the vibration of the enclosure
wall is greater at those frequencies than at other frequencies, thus producing a coloration of the
acoustic output. While reducing such timbre involves reducing the amplitude of the enclosure
wall vibration for a given excitation level, such amplitude is primarily determined by the
enclosure stiffness at low frequencies. And at high frequencies it is mainly determined by the
mass per unit area of the wall. The conventional lautzers are designed to have quite thick wood
walls in order to provide adequate rigidity and a large mass per unit area. The large mass per
unit area has the advantage of reducing the oscillation frequency at high frequencies, but has two
notable drawbacks, as these 02 defects are due to the fact that the enclosure wall constitutes a
resonant system is there. The first drawback of increasing the mass per unit area of the enclosure
wall is that the Q-factor, including the longer "echo time" is increased. By analogy to the values
used for room acoustics, the echo time of the loudspeaker enclosure can be defined as the time at
which the wall vibration amplitude decays by 60 dB after the excitation has ended. According to
such a definition, a reverberation time of up to 0.6 seconds is not unusual for a conventional
enclosure with wooden walls. The second drawback of increasing the mass per unit area of the
enclosure wall is the reduction of the resonant frequency. Considering first the loudspeaker
enclosure with only one drive unit, the amplitude of the air pressure oscillations within the
enclosure decreases as the oscillation frequency of the drive unit increases 710. Thus, the wall is
more sensitive and "actuated" at low frequencies, resulting in low frequency resonances being
more severe than high frequency resonances. Low frequency signals are provided exclusively or
mainly to one drive unit (usually referred to as a "woofer" or bass loudspeaker), high frequency
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signals, assuming that there are just two drive units for simplicity. Such that the signal is
provided through a so-called cross-over network in which the signal is exclusively or mainly
mainly provided to the other drive unit (commonly referred to as "tweeter" or high-pitch
loudspeaker) K. In the case of a loudspeaker-enclosure with one or more drive units, the treble
loudspeaker may be such that the air adjacent to the rear face of the diaphragm Q of the treble
loudspeaker does not communicate with the air in the main part of the enclosure? There are
additional factors in terms of guaranteeing.
Thus, the enclosure wall is not activated to any significant extent at frequencies which are only
handled by substantially high-pitched loudspeakers, which are usually frequencies above 3 KHz.
By analysis as described above, it has been proposed to use materials in the form of two thin
aluminum sheets separated by a honeycomb structure of, for example, an aluminum alloy, as the
loudspeaker-enclosure wall V-constituting material. Such materials have a large ratio-to-mass
ratio, which results in a resonant frequency higher than that of a conventional wooden cabinet.
Higher resonance frequencies give shorter echo times, assuming that the Q value is kept
constant. This is because the Q factor is inversely proportional to the loss of energy per cycle of
the energy of the system caused by the vibration of the vibration system, and at higher
frequencies there are more cycles per time, so an even greater proportion of vibrational energy is
It is lost per unit time. In fact, wall spout-mass ratio increase 77 first also increases Qfi ['& only
increases it to only partially offset the echo time reduction caused by the high resonant
frequency. Thus, the net effect of the increased wall-to-wall ratio is to reduce the reverberation
time of the enclosure. However, difficulties arise because of the so-called coincidence effect. The
theory underlying this coincidence effect is somewhat complicated, and it is possible to consider
the stiffness effect by the rear face of the drive unit (and thus by the ability of the enclosure wall
to transmit the sound generated in the enclosure (not by the wall vibration) It is convenient. The
coincidence effect, which is not a simple resonance phenomenon (in that it does not occur at a
single frequency), manifests itself as an increase in the ability of the wall to transmit sound with a
frequency above its critical frequency. Such critical frequency is directly proportional to the
square root of the texture per unit area of the wall and inversely proportional to ?, which is a
measure of the wall's flexural rigidity. Thus, for walls with low feed-to-mass ratios, the critical
frequency is low and the coincidence effect is a significant disadvantage. Therefore, it has been
proposed to fill the loudspeaker enclosure with such a wall at least partially with an acoustically
absorbing material to reduce the amplitude of the sound waves incident on the inner surface of
the wall f, -U No. Applicants have conducted tests to investigate the tonalities caused by the
vibration of the walls of the loudspeaker-enclosure. These tests are measured relative to the
sound level "4f from the housing wall, relative to the sound level from one or more of the drive
units, absolutely relative to the input signal provided, and the enclosure The reverberation time
of the housing was measured to determine the different levels of sound from the housing wall
and the inherent effectiveness of the different reverberation times.
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A brief outline of the procedure of these tests is given below. A number of different structures t /)
9 Udspicar enclosures were tested in series. In the first test, the loudspeakers are placed in a
reverberation room, and the entire acoustic system from the loudspeaker system, ie the acoustics
from one or more units and the acoustics from the enclosure wall are picked up by the indoor
microphone It was done. The signal given to the loudspeaker is pink noise (equal to b energy per
octave across the frequency band under investigation? Random noise), the output from the
microphone was given to the spectrum analyzer. A test like this involves leaving an enclosure
similar to the loudspeaker-car enclosure sealed on the front of the loudspeaker-arrangement
except that the drive unit is removed in conjunction therewith. The loudspeakers are being
repeated by the enclosure. The output from the spectral analysis v device at this time is indicative
of the sound emitted only by the wall of the double housing thus made, this sound level being
that of the original loudspeaker enclosure wall. It closely approximates the acoustic level
generated by the vibration alone, and thus the level of this acoustic, ie the loudness-the strength
of the signal given to the car, and also the acoustic level to the acoustic level from the drive unit.
The level is confirmed-having one or more drive units shielded by the second enclosure as
described above, the loudspeaker-the enclosure being different from the original loudspeaker
system-the remainder Used for testing. In the second test, an "a-covered" loudspeaker is placed in
an anechoic chamber with a microphone, and a signal indicating the emission of sound is given
to the loudspeaker and the weakness of the output signal from the microphone is It has been
tested to confirm the echo time of the 'shielded' loudspeakers, but it has been shown that it
closely approximates the original Lou Fs to the echo time of the wall of a car enclosure In the
third test, the loudspeaker was again placed in the anechoic chamber with the microphone and a
music signal was given to the loudspeaker from eg a small disc player. The same signal was also
given to one head worn by a listener outside the room. The output from the microphone was
mixed with the original signal being given to the head 7 on at a level lower than the original
signal level to a degree determined by the first test.
The level at which the signal from the microphone is mixed can of course be varied above or
below the level considered to be the correct level, ie the level determined by the first test, and the
signal from the microphone is also added and removed. Switch (switch in or out). These tests not
only confirmed that it would be desirable to have a low level of acoustic power and short echo
times on the housing wall, but also the enclosure wall in that it substantially impaired the
inherent effects experienced by the listener. It has been confirmed that the maximum acceptable
sound level from A increases with decreasing echo time. OBJECTS OF THE INVENTION The
present invention aims to further improve the performance of the prior art loudspeaker
enclosures as described above. SUMMARY OF THE INVENTION The present invention comprises
a rectangular box-like housing comprising top and bottom walls, a front wall, a back wall, a left
wall and a right wall, each of these walls being formed by wood panels; Disposed from the top
wall to the bottom wall and extending from the left wall to the right wall, the planes being
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substantially parallel to one another and substantially parallel to the opposing walls of the
opposing housing walls The first set of spaced apart reinforcing panels and the plane thereof are
arranged parallel to one another and substantially parallel to the opposite pair of opposing
housing walls. A hollow reinforcing structure adapted to include a second set of reinforced
panels, wherein the first set of reinforcing panels is secured to the second reinforcing panel to
substantially Cross to cross the reinforcement panel of A loudspeaker-enclosure, whereby the
reinforcing panel together with the housing wall forms a plurality of rectangular parallelepipedic
compartments, and holes are provided in the reinforcing panel to provide communication
between adjacent compartments. To provide The reinforced panel of the loudspeaker enclosure
according to the invention has a lower frequency (on the basis of the above analysis and the
results of the applicant's test described above) compared to the conventional loud-speaker car
enclosure with a wooden wall ?. Provide a slight reduction in the amplitude of the vibration of
the enclosure wall at or below the lowest resonance frequency, but in any case the improvement
is not as significant as justifying that the complexity of the structure has increased, the enclosure
Expected to be long echo time CI) if the wall is a wood panel that inevitably has a relatively high
quality, per unit unit. It was expected.
In particular, it was expected that the intrinsic performance would not be better, at least below
the critical frequency of the enclosure, than the performance of the previously proposed metal
sanded-inch structure as described above. Surprisingly, the test along the edge described above is
essentially that the reinforcement panel reduces the amplitude of the vibration of the enclosure
wall at low frequencies, f, not CI, but substantially reduces the reverberation time It proves that
the result which substantially improves the performance of the engine was obtained. Although a
decrease in echo time indicates that the stiffening panel significantly increases the damping, the
mechanism for increasing the damping is not completely understood at present. Advantageously,
the reinforcing panels of at least one of the sheets of reinforcing panels are integral and extend
over the interior of the housing. The reinforcing panels of the other set of paper of the
reinforcing panels are made by a band, when the reinforcing panels of one set of the paper of
reinforcing panels are integral and extend over the inside of the housing Some of which extend
between the adjacent panels of said one set and are fixed to these panels, and the remaining
bands extend between the panels of one set and the housing wall It is made 5 fixed to these
panels and the housing wall. A given reinforcing panel forming strip is in fact coplanar but does
not have to be coplanar. However, the two sets of reinforcing panels in the reinforcing panel are
integral with each other in the interior of the housing, each reinforcing panel has a groove, and
the groove in each reinforcing panel is the other set of reinforcing panels. It is desirable to be
made acceptable. Advantageously, one set of reinforcing panels is fixed to the other set of
reinforcing panels. The reinforcing panels are preferably made to be fixed together by an
adhesive. The reinforcing panels are advantageously made of wood and are preferably made of
hardware. Plywood is another desirable material. The thickness of such wood reinforcing panels
will vary with the dimensions of the housing and with the spacing between adjacent panels of
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each set, but a thickness of 2 to 6 u is usually found to be suitable Power. Instead of using wood
reinforcement panels, reinforcement panels of plastic material can also be used, in which case
the hollow reinforcement structure can be of one-piece construction. As such, the hollow
reinforcing structure can be formed by injection molding. The reinforcing panel is
advantageously fixed to the housing wall.
If the stiffening panels are fixed to the housing wall, these stiffening panels are put in tension or
in compression so that the # r @ ratio is improved. Advantageously, the reinforcing panel is fixed
to the housing wall by means of an adhesive, the adhesive used being not in a brittle state, but an
adhesive which allows it to be fixed in a rubbery state is desirable. An adhesive of this type which
has been found to be satisfactory is a polyvinyl acetate adhesive. The same considerations apply
to the choice of adhesive used to secure one set of wood reinforcement panels to the other set of
wood reinforcement panels. As explained above, although the mechanism by which the
reinforcing structure damps the vibrations of the housing wall is not completely understood, an
adhesive that fixes in a rubbery rather than brittle state for the above purpose Where such is
used, such an adhesive substantially contributes to the damping provided by the reinforcing
structure. The inner surface of the reinforcing structure and at least the housing wall not
designed to receive the drive unit can be sprayed with a silencer material, which is also fixed to
the edged housing wall of the reinforcing panel Also, if the reinforcing structure is not a onepiece structure, it serves to secure one set of reinforcing panels to the other set of reinforcing
panels. Asphalt and filler mixed bituminous materials have been found to be suitable for this
purpose, which also substantially contribute to the damping provided by the reinforcing
structure. It will be appreciated that for sets of panels which serve as reinforcing structures,
these panels must be tightly fitted within the housing or the edges of the panels must be fixed to
the housing wall. Furthermore, adhesives that have been found to work satisfactorily with wood
panels, at least as a general rule, require wood-to-wood contact. The edges of the stiffening panel
can be received in the grooves of the housing wall in order to avoid the need for tight tolerances
as otherwise required for tight tolerances. In that case, it is only necessary that the thickness of
the reinforcing panel be correctly associated with the width of the groove. Advantageously, the
section bounded by the reinforcing panel is of substantially square cross section with the housing
wall. In that case, each housing wall is reinforced substantially equally by the reinforcing panel in
two directions parallel to the two opposing opposite edges of the wall.
Advantageously, each said set of reinforcing panels consists of at least six reinforcing panels,
preferably ten thousand of said sets consisting of at least five reinforcing panels. Starting from a
loudspeaker of a given size and making it of significantly larger size, it is possible to increase the
number of reinforcing panels used and / or to increase its thickness is there. It is preferred that
at least some of the compartments be sound absorbing material. It has also been found that it is
desirable for at least most of the compartments to speak of such materials, and an arrangement
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such that all compartments are rich in such materials and L-dike. The considerations relating to
these matters are explained below in connection with the Lau Y-speaker system described below
with reference to the accompanying drawings. The sound absorbing material may be in the form
of a block of open cell plastic material, with a block of open cell polyester foam or a suitable open
cell polyether foam. Loudspeaker, which can be in the form of acoustic fibers, waste wool, rock
wool or glass fibers, which are inlaid with sound absorbing material instead of the abovementioned-the front of the enclosure at least one loudscar-car drive unit Advantageously
arranged to be received, one set of reinforcing panels lies parallel to the side walls of the housing
and the other set of reinforcing panels lies parallel to the top and bottom walls of the housing.
The housing wall is advantageously made of particle pads, sometimes referred to as tip pads. It is
made of wood particles or chips embedded in a resin matrix and has a high density of 1 fir-f.
Veneers are usually placed on the outside of the wall. A suitable thickness for a wooden housing
wall is usually in the range of 10 to 20 iL11, and a suitable mass per unit area of the wall is
usually in the range of 7 to 12 per square meter. The invention also provides a loudspeaker
enclosure according to the invention together with one or more loudspeaker-drive units mounted
in a housing wall. The primary walls of the housing with one or more loudspeaker-drive units
may also be vented to allow the loudspeaker-enclosure to constitute a Helmholtz resonator
device. Two loud speaker-car systems configured according to the invention are described below
by way of example with reference to the accompanying drawings.
Embodiments of the Invention The 'rS first loudspeaker system constructed according to the
invention refers to one loudspeaker enclosure and two loudspeaker drive units. Loudspeaker car
enclosures include a number of intersecting reinforcing panels which form a compartmental
structure. All compartments refer to sound absorbing material, and the holes in these panels are
adapted to provide communication between adjacent compartments. Crossing reinforcement
panels are formed by a hardboard, each section being of square cross-section as viewed in a front
compatible view. The entire compartment structure is rigidly fixed together by the use of an
adhesive on the forefoot part, and also rigid on the enclosure wall except in areas not blocked by
the loudspeaker drive unit and the air vents. It is fixed. Grooves are formed in the enclosure wall
for receiving free edges of the compartment structure, these edges being fixed in the grooves by
an adhesive. The preferred adhesive used to construct the enclosure is a PTA (polyvinyl acetate)
adhesive. The sound absorbing material is a foam bottom resin material which is made into a
profile and inserted into the individual compartments. Referring to FIG. 1 of the drawings, the
loudspeaker enclosure includes a rectangular box-like housing generally designated 100, which
comprises a top wall 102, a bottom wall 104 and a front wall Not shown), back wall 106, left till
wall 108, and right side wall 110, each of which is a wood panel. Each panel is veneered at a
thickness of approximately 15 u to yield a quality t (including veneers) per unit of about 9 'Kll
per square meter. The front wall is omitted in FIG. 1 to show the inside of the enclosure. A pair of
Lau V speaker drive units (not shown) are attached to the front wall soil in the usual manner. The
wood wall which forms the housing wall is made of hardwood. A hollow reinforcing structure,
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generally indicated at 200, is disposed within the housing 100, but the loudspeaker-drive unit
and the circular vent (that c /) location is indicated by the circular 330 in FIG. Leaving room for
free space in the vicinity). The hollow reinforcing structure 200 is fixed in place by an adhesive
and is rigidly attached to the top wall 102 to the bottom wall 104, to the front wall (not shown)
to the back wall 106, and to the left wall 108ff right (IIl wall 110). Connected to
The hollow reinforcing structure 200 consists of six panels 1.3 panels 2 and three panels 3
(described in more detail below), the planes of which are parallel to one another and the top wall
102 and the bottom wall 104 respectively. Wc- set of nine spaced reinforcing panels and two
panels 4 and 2 of wc- arranged parallel to each other (thereby allowing the loudspeaker system
to extend horizontally in the normal orientation position) Of five panels 5 (described in more
detail below), the planes of which are parallel to one another and parallel to the left 11th wall
10B and the right side wall 110 (thereby the loudspeaker system in the normal orientation
position B) with two spaced reinforcing panels. The first set of horizontal stiffening panels 1.2
and 3 intersect with the second set of vertical stiffening panels 4 and 5 and rigidity to these
panels by sparging the adhesive in its crossover position Fixed. A number of rectangular
parallelepiped sections 250 are created in this manner. Circular holes (described in more detail
below) are formed in the reinforcing panel to provide communication between adjacent
compartments, with all the compartments as described in more detail below (see FIG. 1). (Not
shown). The reinforcing panels 1 to 5c /) shape are shown in FIGS. 2 to 6, respectively. The
loudspeaker-enclosure is comprised of six reinforcing panels 1 of the shape shown in FIG. 2,
three reinforcing panels 2 of the shape shown in FIG. 3, and three reinforcements of the shape
shown in FIG. The panel 3 and the two well-formed reinforcement panels 4 shown in FIG. 5 and
the two reinforcement panels 5 of the shape shown in wc 6 are used. All reinforcing panels
1.2.3.4.5 are made of hardboard of 5IJl thickness. Each reinforcement panel 1. Is roughly
rectangular in shape with a length of 25511 m and a width of 230 auE. The transverse edges of
each reinforcing panel 101 have a rectangular recess 11 centrally located at one of the
dimensions 15 О 73 ? ?, with four grooves 12 parallel to one another and parallel to the
longitudinal axis of the reinforcing panel. Starting from the edge, it ends in half along the length
of the reinforcing panel. The two outermost grooves are open to the lateral edge and the two
inner grooves are open to the recess 11. Each groove is 6 tin wide and is symmetrically arranged
around the longitudinal axis of the reinforcing panel, and the groove axes are spaced at a pitch of
46 u.
Each reinforcing panel 1 comprises 27 circular openings 13 of 19 JL IIl in diameter. The centers
of them are arranged in five rows with 42 first intervals in the longitudinal direction and 461 jE
in the lateral direction. The arrangement of these openings 13 is such that the six openings in the
vicinity of the recess 11 are not provided which would be necessary in the case of a perfectly
symmetrical arrangement so as to avoid getting too close to the edge of the material Symmetrical
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about the lateral and longitudinal axes of the reinforcing panel 1. The reinforcing panel 2 of
which only one is shown in FIG. 3 is provided with a larger rectangular recess 21 and with 20
openings 23 arranged in 4 (/ J 5 V) rows. Is different from the reinforcing panel 1 only in the
following points. The recess 21 has a size of 90 О 186 U, and four grooves 22 open in this
recess. All the other dimensions (the same as the dimensions given to the engineering
reinforcement panel 1, the material is also a hardboard. The reinforcing panel 3 of which only
one is shown in FIG. 4 differs from the reinforcing panel 1 only in that recesses 31 of different
dimensions are provided and 28 ? openings 33 are provided. Four grooves 32 are provided, the
dimensions being the same as the dimensions given to the panel 1 and the material is also nodeF. Reinforcement panels 1.2 and 3 extend horizontally through the loudspeaker enclosure, while
reinforcement panels 4 and 5 extend vertically. Each reinforcing panel 4 (see FIG. 5) is roughly
rectangular in shape and has a height h of 450 u and a depth d of 255 ? and is made of a 3 u
thick re-hardboard. The side edge of one of the long edges of each reinforcement panel 4 has a
symmetrical centrally located recess 41, with nine open end grooves 42 parallel to one another
and of this reinforcement panel It extends inwardly from the other long edge of the second edge
of the short edge. Each groove 42 has a length equal to half the depth of the reinforcement panel
4. The recess 41 is wedge-shaped in shape, and is parallel to the longitudinal axis of the
reinforcing panel 4 and has a wall 1 on the fIk wall 4 which forms one of the parallel N portions
of the wedge. The rib-shaped side wall 41 ? expands towards the one side edge of the
reinforcing panel 4, the expansion angle ? being 200. The mouth of the recess 41 has a length
m of 164 u and this recess has a depth n of 90 m1 m. The reinforcing panel 4 comprises 52
circular openings 43 of 19 u + diameter, the centers of these openings being spaced at a pitch of
45 II JI in the longitudinal direction and at a pitch of 42 sua in the lateral direction, respectively.
The arrangement of these openings 43 is in the lateral direction of the reinforcing panel 4 except
that the openings related to the eight additional openings necessary to obtain perfect symmetry
are not provided due to the presence of the recesses 41. And symmetrical about the longitudinal
axis. Each groove 42 had a width of 3 su + and the axis of the grooves had a spacing of 451 Lll.
The reinforcing panel 5 of which only one is shown in FIG. 6 is provided with recesses 51 having
different shapes, and is provided with a recess 710 having a rectangular shape 710, and the 44
openings 53 are recesses 51 and 55. Is different from the panel 4 only in that it is provided in
consideration of. A nine groove 52 is provided in the same manner as the groove 42. The recess
51 is enlarged towards the mouth of the symmetrical recess in the reinforcing panel 5c) the rear
wall 51 'parallel to the longitudinal axis, the bottom side wall 511 parallel to the lateral axis of
the reinforcing panel, and the side wall 51'. Has an inclined side wall 51 ? ? ?, and its
expansion angle ? is 10 ?. The rectangular recess 55 has dimensions of 15 О 56 mjm and its
top edge (I! 6) are spaced 27.3 m1 m from the top of the reinforcing panel 5. Now, considering
the recess 51, the outermost end g of the sidewall 51 ? ? ? of this recess is at a 135 first
distance from the top edge of the reinforcing panel 5, and the sidewall 51N of the recess is 408
th from the top edge In the distance. The recess 51 has a depth of 90 ut. All other dimensions are
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the same as given for the reinforcement panel 4 and the material is also a node board. The
sixteen reinforcing panels described above are interdigitated together by grooves to form a
composite structure of intersecting reinforcing panels as shown in FIG. 7, which constitute a
reinforcing structure 200. It is At each intersection, the vertical reinforcement panel groove
receives the horizontal reinforcement panel thickness to its end, and the horizontal
reinforcement panel groove is adapted to receive the vertical reinforcement panel thickness . The
recesses 11.21.31.41.51 and 55 delimit a space for accommodating the rear of the respective
drive unit of the lever system and a space in the vicinity of the ventilation holes. It is possible to
assemble these sixteen reinforcing panels into a reinforcing structure 200 using the respective
cross-over adhesive and then introduce them into the housing 100 which has been relinquished.
Through 5 are preferably fitted one at a time in mating grooves (not shown) provided in the
housing wall. The reinforcing panels 1.2 and 3 can be inserted into the housing 100 with the
front wall of the housing 100 removed instead of letting the pants be inserted into the chest of
the The reinforcing panels 4 and 5 can be grooved in place.
The reinforcing structure 200 forming the inner surface of the housing 100 and the
compartments, if desired, for example, will bond intersecting reinforcing panels to one another
and to the wall of the housing 100 (when no other adhesive is used), or A vibration damping
compound such as a liquid bituminous material can be sprayed which serves as an adhesive to
aid adhesion. An acoustically absorbing material in the form of a block 300 of synthetic resin
foam is inserted into each section 2520 of the reinforcing structure 200. The schematic drawing
of the assembly is shaded by 50 cv section m 250 whichever receives a block of foam of
dimensions 42x42x250 # L11 and a short block is inserted in the other section (not shaded)
Show that. A circle 310 indicated by a broken line indicates a position of the high frequency
drive unit, a circle 320 indicates a main drive unit position rIIL, and a circle 330 indicates a
circular ventilation hole ci) position IR of the front panel of the housing 100 . A 190 section 250
receives a block of short foam to leave a free section behind the main drive unit CI) 'flk plane and
behind the circular vent. These sections do not allow the sound-absorbing material to come in
contact with the main drive unit cone (the high frequency drive unit is of enclosed construction
and therefore does not require an opening) and also the unwanted attenuation of the Hermholtz
resonance . It is left because free movement of air must be allowed near the air vents to avoid
The vents can be simple circular openings or can be short pipes enriched, but in any case about
50 to 1001 ul (1) free sections must be left behind the vent inner end You must. The sound
absorbing material helps to reduce the amplitude of the resonances in the individual
compartments, but the large pressure fluctuations in the I.udging are such that the cone of the
loudspeaker drive unit has an unacceptably low output. Care must be taken to avoid causing
attenuation. The proper one for sound absorption is essentially a compromise choice for the
given size and shape of the enclosure, and in some instances some segmented residuals ?
without acoustic absorbing material are desired May be The second enclosure according to the
invention has the advantage that the vents have been omitted and a block of foam of full length
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has been used in the compartment in the vicinity of the location where the vents were in the first
enclosure. Except for the same as the first enclosure. In lieu of the bar V-board, the reinforcing
panels can be made of other suitable materials, but such materials are preferably plywood.
The loudspeaker-enclosure described with reference to the accompanying drawings may be a
single two Udsus-car drive unit, or more than two such units instead of using two such units as
described above. It can be a unity stomach. The dimensions of the various components described
above are merely examples of suitable dimensions, and the invention can be applied to various
loudspeaker enclosures over a wide range of dimensions. It has been found that it is usually
desirable to use a larger number of reinforcing panels and / or thicker reinforcing panels in large
enclosures as described above. The main part of the loudspeaker enclosure is rectangular, and
the reinforcing panels of one set are to be intersected substantially at right angles with the
reinforcing panels of the other set throughout the description of the present specification, which
is based on the claims. However, the invention is not limited to the loudspeaker enclosure or
loudspeaker system whose housing is shaped as described above, and the reinforcing panels do
not necessarily have to be orthogonal to one another, It should also be recognized that they do
not have to abut perpendicularly to the housing wall. However, in this case, it is anticipated that
the resulting reinforced structure will be more difficult to manufacture (aside from where the
reinforced panel is made of a plastic material and the structure is a unitary structure), and at
least some Reinforcement panels are not the opposing walls of the housing, but may extend 5
between adjacent reinforcement panels (though rs provides additional useful advantages over
conventional enclosures It is expected that there will not be a significant improvement over the
advantage obtained when the panels are arranged orthogonal to one another and also to the / S
wall. As described above, it can be seen that the present invention provides a loudspeaker
enclosure that performs better than prior art loudspeaker enclosures.
[0002]
Brief description of the drawings
[0003]
???
FIG. 1 is a schematic perspective view of the loudspeaker enclosure of the first system of the
invention with the front wall removed. FIG. 2 is a plan view of a first shape of a reinforcing panel
used for an enclosure. ?? 3 is a plan view of a second shape of the reinforcing panel used for
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the enclosure. FIG. 4 is a plan view of the third shape of the reinforcing panel used for the
enclosure. FIG. 5 is a side elevational view of a fourth configuration of reinforcing panels used in
the enclosure. 'W, 6 is a side elevational view of the fifth configuration of the reinforcing panel
used in the enclosure. FIG. 7 is a perspective view of the various stiffening panels as assembled 1
░ FIG. 8 is a front compatible view of the stiffening panel assembly shown in FIG. FIG. 9 is a
drawing of a schematic assembly of a loudspeaker and a car enclosure. 1.2,3.4.5 и и и и и и и и
reinforcement Tsuyaneru 21.31.41.51.55 ... recess 22.32.42.52 ии ииииииииииииииииииииииииииииииииииииииииииииииииииииииииииииии
1 1 104 и и и и и и и и bottom wall 106 и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и и
и и и и и и и и и и и и и hollow reinforcement structure 250 ии .... Section
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