This application is a U.S. National Phase application of PCT/EP2014/071842, filed on Oct. 13, 2014, claiming the benefit of FR Application No. 13 60616, filed Oct. 30, 2013, both of which are incorporated herein by reference in their entireties.
The present invention relates to a loudspeaker enclosure, of the type including:
the mobile membrane including a peripheral edge situated opposite the inner edge of the member and forming a closed loop.
In order to preserve a good tone quality and spatial coherence favoring the obtainment of a wide and deep stereophonic image, a loudspeaker enclosure must have an amplitude and phase response that are as linear as possible for the span of audible frequencies, favoring the direction of the listening zone over its entire span in terms of width and height.
Traditional loudspeaker enclosures have a noticeable limitation in obtaining a spatially coherent sound, namely the interference phenomena between the acoustic radiation of loudspeakers making up primary acoustic sources, and the acoustic radiation of secondary acoustic sources created by diffraction phenomena.
The invention aims to propose a loudspeaker enclosure better limiting diffraction phenomena.
To that end, the invention relates to a loudspeaker enclosure of the aforementioned type, wherein the mobile membrane and the member have a shape adapted so that, over a continuous portion of the peripheral edge representing at least 25%, preferably at least 50%, still more preferably at least 90%, of the length of the peripheral edge, for any first point of the continuous portion and any second point situated on the inner edge in a location such that the distance between the first point and the second point is minimal, the mobile membrane has, at the first point, a first tangent plane, and the outer surface of the member has, at the second point, a second tangent plane, the first tangent plane and the second tangent plane being substantially coincident with one another.
According to specific embodiments, the acoustic enclosure includes one or more of the following features:
The invention will be better understood upon reading the following description, provided solely as an example and done in reference to the drawings, in which:
A loudspeaker enclosure 10 according to the invention is described in reference to
The enclosure 10 comprises at least one first loudspeaker 30A having a first convex mobile membrane 32A, the convex side being turned toward the outside of the enclosure, and a member 12 surrounding the first mobile membrane 32A and including an outer surface 12A bounded by an inner edge Γ′ situated across from the mobile membrane 32A.
The member 12 is advantageously a box, as in the illustrated example, or a second loudspeaker (not shown) surrounding the first loudspeaker 30A, or a grate (not shown) covering this second adjacent loudspeaker.
The first mobile membrane 32A includes a peripheral edge Γ situated across from the member 12 and forming a closed loop.
As shown in
The first tangent plane PM and the second tangent plane P′M are substantially coincident with one another.
“Substantially coincident” means that the first tangent plane PM and the second tangent plane P′M do not substantially differ from one another to the human eye. For example:
The outer surface 12A of the member 12 is configured so that, for any third point M″′ (
In the example illustrated in
The enclosure 10 outwardly has a generally oblong shape with axis X-X, more specifically with a lancet shape with a front end 16 having a spherical shape. The front end 16 outwardly forms a spherical zone 17 whereof the center O is positioned on the axis X-X.
The spherical zone 17 is extended toward the rear by a protuberance 18 in which the amplifier 14 is housed.
Over its length, the body 12 has a planar shape in the lower part to form a foot 20 making it possible to set the enclosure in a stable position on a horizontal surface. The enclosure 10 symmetrical around a plane perpendicular to the surface of the foot 20 and passing through the axis X-X.
In the plane of
In the plane of
The enclosure 10 includes a plurality of loudspeakers 30A, 30B, which are for example woofers. Each loudspeaker of said plurality respectively comprises a mobile membrane 32A, 32B.
Woofers refer to loudspeakers suitable for diffusing acoustic waves with frequencies lower than 1000 Hz, preferably lower than 500 Hz, still more preferably lower than 150 Hz.
The enclosure 10 for example includes two first woofers 30A, 30B positioned symmetrically relative to the axis X-X and emerging in the spherical space 17. The two loudspeakers are positioned along the same axis Y-Y extending perpendicular to the axis X-X of the enclosure. The axis Y-Y is parallel to the bearing surface 20. The axes X-X and Y-Y are secant to the point O forming the center of the spherical region 17.
The loudspeakers 30A, 30B form an angle equal to 360° divided by two, therefore 180°, between them around a distribution axis Z-Z substantially perpendicular to the axis X-X and substantially perpendicular to the axis Y-Y.
These two loudspeakers have a membrane 32A, 32B in the form of a solid spherical cap with the same curvature as the spherical zone 17. The spherical membrane extends the spherical zone 17 substantially continuously, when the membrane 32A, 32B is idle.
Thus, preferably, the spherical zone 17 of the box and the surface of the spherical membranes 32A, 32B of the two woofers 30A, 30B define a spherical surface with an expanse at least equal to the surface of revolution created by rotation of a spherical membrane 32A, 32B of a woofer 30A, 30B over at least 180° around an axis X-X perpendicular to the axis Y-Y of the two spherical membranes 32A, 32B.
An annular peripheral interval 34A, 34B separates the membrane 32A, 32B of the speakers from the spherical zone 17. Preferably, the width i of this annular interval between the membrane of each woofer and the box, measured radially in the plane of the circumference of the membrane of the loudspeakers, is smaller than 1/100th of the perimeter of the membrane of the loudspeaker. Preferably, it is smaller than 1/200th, and still more preferably smaller than 1/400th. Thus, for example for a loudspeaker with a circumference of 500 mm, this width is smaller than 5 mm, preferably smaller than 2.5 mm, and still more preferably smaller than 1.25 mm.
Advantageously, the diameter d of the circle defined by the spherical cap forming the membrane 32A, 32B of each woofer is larger than half of the diameter denoted D of the spherical zone 17 of the box. Preferably, it is greater than ⅔ of this diameter D, and still more preferably greater than ¾ of this diameter ¾.
For example, for a diameter d of the woofer of 160 mm, the diameter D of the spherical zone is then comprised between 320 mm and 220 mm.
The two loudspeakers 30A and 30B are identical and are mounted back-to-back. Thus, the stationary parts of the two loudspeakers form chassis 42A, 42B that are rigidly connected to one another. Furthermore, these chassis are secured using any appropriate means to the box 12.
Said plurality of loudspeakers 30A, 30B is advantageously positioned such that the reaction forces of the mobile membrane 32A, 32B on the chassis 42A, 42B have a zero sum.
Advantageously, the membrane is made from metal, in particular aluminum, magnesium, titanium. Thus, the membrane is not very deformable. It is connected to the chassis of the loudspeaker by a sealing device, for example a bellows 48A, 48B. According to alternatives, the membrane is made from plastic, composite material, paper, etc.
The two woofers 30A, 30B are designed such that the maximum angular travel along the axis Y-Y of the membrane of each woofer is greater than 1/50th of the diameter D of the spherical zone 17 of the box. Advantageously, this travel is greater than 1/20th of the diameter D of the spherical zone 17, and still more preferably greater than ⅕th of the diameter D of the spherical zone 17.
The enclosure 10 further includes a loudspeaker 50, for example a mid-range loudspeaker, positioned along the axis X-X and emerging in the spherical zone 17. The loudspeaker 50 has a membrane 52 forming an incomplete spherical cap open-worked at its apex. This spherical membrane 52 has a radius equal to the curve radius of the spherical zone 17 and extends in the extension of that spherical region to form a substantially continuous spherical surface when the membrane 52 is idle.
A mid-range loudspeaker refers to loudspeaker suitable for diffusing acoustic waves at frequencies from 300 Hz to 3 kHz, or from 150 Hz to 6 kHz.
Preferably, a tweeter 60 is positioned axially at the center of the loudspeaker 50.
A tweeter refers to a loudspeaker suitable for diffusing acoustic waves with frequencies from 3 kHz to 20 kHz, or from 1 kHz to 40 kHz.
The tweeter also has a spherical membrane with a radius equal to the radius of the spherical zone 17 and fits in the enclosure of the spherical zone 17.
Owing to the features of the enclosure 10 described above, the convex mobile membranes of the loudspeakers marry the shape of the box on either side of the intervals separating the mobile membranes and the box. Thus, the diffraction phenomena are greatly reduced.
Furthermore, one can see that with such an enclosure, the woofers placed back-to-back have identical movements of their membrane, the chassis of the two loudspeakers remaining immobile relative to the box, the reaction forces applied by the membranes on the chassis canceling each other out.
In reference to
Only the differences with respect to the enclosure 10 shown in
The enclosure 100 is pressed against a wall 110 defining a planar surface 110A.
The wall 110 is for example a vertical wall, or the top of a table (not shown).
The member 12 comprises a radially distal peripheral portion 112 relative to the mobile membrane 32A, and a radially proximal inner portion 114 relative to the mobile membrane 32A.
The peripheral portion 112 is for example convex. The peripheral portion 112 defines a closed peripheral edge B. The peripheral portion 112 surrounds the inner portion 114.
The inner portion 114 is for example concave.
Between the inner portion 114 and the peripheral portion 112 is an inflection zone S, which is a closed line in the illustrated example.
The member 12 has a shape adapted so that, over a continuous portion B′ of the peripheral edge B representing at least 25%, preferably at least 50%, still more preferably with 90%, of the length of the peripheral edge B, for any point N of the continuous portion B′, the outer surface 12A of the member 12 has, at the point N, a third tangent plane PN.
The third tangent plane PN and the planar surface 110A are substantially coincident.
“Substantially coincident” means that the third tangent plane PN and the planar surface 110A do not substantially differ from one another to the human eye. For example:
The enclosure 100 makes it possible to minimize the diffraction and reflection related to the presence of the wall 110 in the immediate vicinity of the enclosure.
Number | Date | Country | Kind |
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13 60616 | Oct 2013 | FR | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2014/071842 | 10/13/2014 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2015/062852 | 5/7/2015 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3925626 | Stallings, Jr. | Dec 1975 | A |
4295006 | Tanaka | Oct 1981 | A |
20070009133 | Gerkinsmeyer | Jan 2007 | A1 |
Number | Date | Country |
---|---|---|
926923 | Jun 1999 | EP |
1162864 | Dec 2001 | EP |
2895201 | Jun 2007 | FR |
08038021 | Apr 2008 | WO |
Entry |
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International Search Report for PCT/EP2014/071842 dated Jan. 14, 2015. |
Preliminary Search Report for FR Application 1360616 dated Jul. 15, 2014. |
Office Action for EP App No. 14783637.3, dated Nov. 29, 2018, 10 pages (with Machine Translation). |
Number | Date | Country | |
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20160360311 A1 | Dec 2016 | US |