Method of manufacturing an acoustic waveguide device and corresponding device

Abstract

The invention relates to a method for manufacturing a waveguide device (100) and a corresponding device comprising an outer shell (CQE) and a core (NYI) which delimit between them an acoustic waveguide channel (CNL1). The acoustic waveguide channel has internal surfaces (SPI, SPE) which define paths for the acoustic waves, which are of the same length (d19max) so as not to introduce a delay gradient between the waves. The invention also relates to an enclosure, and a corresponding set of enclosures. Figure for abstract: Fig.2

Description

Title of the invention: Method for manufacturing an acoustic waveguide device and corresponding device FIELD OF THE INVENTION

[0001] The present invention relates generally to acoustic wave guiding devices, also called waveguides. PREVIOUS ART

[0002] Waveguides are known from the state of the art which make it possible to direct in a controlled manner the propagation of sound waves emitted by a loudspeaker.

[0003] In order to control the directivity of sound sources, so-called waveguide elements are used in acoustics. Depending on the type of control desired, it may be desired that the waveguide does not introduce a delay gradient regardless of the path of the wave between the input and output surfaces of the waveguide. An example of desired control is that acoustic speakers of the same type, preferably identical, juxtaposed can radiate in phase in order to generate constructive acoustic interference (summation), and thus obtain greater energy in their radiation space making it possible to increase the acoustic range.

[0004] The delay gradient can be expressed in a simplified view by the difference in length of the paths traveled by the acoustic waves within this waveguide.

[0005] Known waveguides are generally designed empirically so that their design is complex, long, tedious and difficult to repeat.

[0006] The aim of the present invention is to propose a new manufacturing method and a new corresponding acoustic wave guiding device (waveguide) making it possible to overcome all or part of the problems set out above. Summary of the invention

[0007] To this end, the invention relates to a method for manufacturing a waveguide device, the waveguide device comprising: - an external peripheral wall, called the external shell, - an internal peripheral wall, called the core, surrounded by the external shell; the outer shell and the core delimiting between them: - an inlet opening which has an annular inlet surface, and to which an acoustic wave generator system is capable of being connected, - an outlet opening, called a mouth, having a rectangular outlet surface, the outer diameter of the annular inlet opening being less than the length of the long side of the rectangle of the outlet opening, and being greater than half the length of the long side of the rectangle of the outlet opening, the set of the two inlet and outlet surfaces having a plane of symmetry, called the vertical plane of symmetry, passing between the two long sides of the rectangle of the outlet surface, and a median plane, called the horizontal median plane, orthogonal to the vertical plane of symmetry, said planes passing through the center of the annular inlet surface and through the center of the rectangular outlet surface, - an acoustic wave guiding channel communicating between the inlet opening and the outlet opening and defined between an inner peripheral surface of the outer shell and an outer peripheral face of the core; characterized in that the method comprises:

[0008] - the generation using a computer system of an external surface and a internal surface of the volume delimited by the waveguide channel between the annular inlet surface and the rectangular outlet surface;

[0009] - manufacturing the outer shell so that the inner peripheral surface of said outer shell is defined in relation to said outer surface of said volume, and the outer peripheral surface of said core is defined in relation to said inner surface of said volume of the waveguide channel; and in that said generation of the external surface and the internal surface of the volume of the waveguide channel comprises the following steps:

[0010] a) cutting of the set of inlet and outlet surfaces along said vertical plane of symmetry and said horizontal median plane to obtain a portion, called the upper lateral portion, of the annular inlet surface, and a portion, called the upper lateral portion, of the outlet surface;

[0011] b) determining a path, called the first exterior path, for a first pair of points comprising a first point of the exterior contour of the upper lateral portion of the entry surface located in the horizontal median plane, and a first point of the exterior contour of the upper lateral portion of the exit surface located in said horizontal median plane; the length of the path being called the reference length;

[0012] c) for a second pair of points comprising a second point of the outer contour of the upper lateral portion of the entry surface, which belongs to the vertical plane of symmetry, and a second point of the outer contour of the upper lateral portion of the exit surface, which belongs to the vertical plane of symmetry;

[0013] determination of a second external path, in the vertical plane of symmetry, which connects said second point of the external contour of the upper lateral portion of the entry surface and said second point of the external contour of the upper lateral portion of the exit surface, said second external path comprising:

[0014] - a first segment, called the opening segment, inclined at an angle of value predefined, called the upper opening angle, relative to the axis of intersection of the two planes between them, and

[0015] - a second segment, called a folding segment, which extends the first segment up to said second point of the outer contour of the upper lateral portion of the entry surface, the length of said second outer path being equal to said determined reference length (dl9max),

[0016] the junction point between the two segments being called the outer vertex;

[0017] d) definition of a plane, called the upper outer vertex plane, passing through said outer vertex and said first point of the outer contour of the upper lateral portion of the output surface, and the center of the rectangular output surface;

[0018] e) for several other pairs of intermediate points, located between the first and second pairs of points, each pair of intermediate points comprising a point of the outer contour of the first upper lateral portion of the entry surface and a corresponding point of the outer contour of the first upper lateral portion of the exit surface:

[0019] determination of an exterior path, called intermediate exterior path, formed by an opening segment and a folding segment which connect said intermediate points of said pair of points, the junction point between said segments belonging to the plane of exterior upper vertices, the length of said exterior path being equal to said determined reference length;

[0020] f) repeating the preceding steps b) to e) with the inner contour of the upper portion of the inlet surface and the inner contour of the first lateral upper portion of the outlet surface, to generate paths, called inner paths, having inner vertices, said inner paths being formed between pairs of points which each comprise a point belonging to the inner contour of the upper portion of the inlet surface and a corresponding point belonging to the inner contour of the lateral upper portion of the outlet surface, the inner contour of the upper portion of the outlet surface corresponding to the segment in the vertical plane of symmetry which results from the section of the outlet surface according to said vertical plane of symmetry and said horizontal median plane;

[0021] g) generating an outer upper surface which passes through the outer paths determined between said pairs of points of said outer contours;

[0022] h) generation of an inner upper surface which passes through the inner paths determined between said pairs of points of said inner contours; (it is understood that step g) can be carried out after e) and step h) can be carried out after f))

[0023] and:

[0024] that is, when the horizontal median plane is not a plane of symmetry, then,

[0025] for the lower lateral portions of the inlet and outlet surfaces which are located, with respect to the horizontal median plane, on the side opposite to said upper lateral portions of the inlet and outlet surfaces, and on the same side of the vertical plane of symmetry as the upper lateral portions of the inlet and outlet surfaces,

[0026] and for a predefined lower opening angle:

[0027] i) repeating the previous steps b) to h) applied to the lower portions to determine outer paths and inner paths associated with said lateral lower portions, and generating a lower outer surface and a lower inner surface as a function of the determined outer paths and inner paths;

[0028] or, when the horizontal median plane is a plane of symmetry,

[0029] ii) generation of a lower outer surface and a lower inner surface by symmetry, with respect to the horizontal median plane, of the upper outer surface and the upper inner surface;

[0030] j) generating an additional lower outer surface, an additional upper outer surface, an additional lower inner surface and an additional lower inner surface by symmetry, with respect to the vertical plane of symmetry, of said lower outer surface, said upper outer surface, said lower inner surface and said lower inner surface;

[0031] said external surface of the volume of the wave guide channel being formed by the joined assembly of said external surfaces;

[0032] said external surface of the volume of the wave guide channel being formed by the joined assembly of said internal surfaces.

[0033] The method according to the invention makes it possible to construct the wave guide channel, and thus the corresponding waveguide, in a simple and repeatable manner and without introducing a delay gradient for the acoustic waves between the input opening and the output opening of the waveguide.

[0034] The method makes it possible to create a waveguide thanks to which the wavefront obtained at the output of the waveguide is almost cylindrical.

[0035] For two juxtaposed speakers, each comprising such a waveguide, the acoustic wavefronts at the output of the waveguides are in phase, which makes it possible to generate constructive acoustic interference (summation). This results in greater energy in the radiation space of the speakers, which makes it possible to increase the acoustic range.

[0036] The method of manufacturing the waveguide or the corresponding waveguide device may also comprise one or more of the following characteristics taken in any technically admissible combination.

[0037] According to one embodiment, for each pair of intermediate points, the ratio of the length between the intermediate point of the outer contour of the inlet surface and the first point of the outer contour of the upper lateral portion of the inlet surface, to the length of the outer contour of the upper lateral portion of the inlet surface, is equal to the ratio of the length between the corresponding intermediate point of the outer contour of the outlet surface and the first point of the outer contour of the upper lateral portion of the outlet surface to the length of the outer contour of the upper lateral portion of the inlet surface.

[0038] According to one embodiment, said pairs of inner contour points comprise: a first pair of points comprising a first point of the inner contour of the upper lateral portion of the inlet surface located in the horizontal median plane, and a first point of the inner contour of the upper lateral portion of the outlet surface located in said horizontal median plane, the length of the path between said points being equal to the reference length; a second pair of points comprising a second point of the inner contour of the upper lateral portion of the inlet surface, which belongs to the vertical plane of symmetry, and a second point of the inner contour of the upper lateral portion of the outlet surface, which belongs to the vertical plane of symmetry;pairs of intermediate points located between the first and second pairs of points, each pair of intermediate points comprising a point of the inner contour of the first upper lateral portion of the inlet surface, and a corresponding point of the inner contour of the first upper lateral portion of the outlet surface; ; the second point of the inner contour of the upper lateral portion of the exit surface being spaced from the second point of the outer contour of the upper lateral portion of the exit surface by a distance equal to the distance between the second point of the inner contour of the upper lateral portion of the entry surface and the second point of the outer contour of the upper lateral portion of the entry surface.

[0039] According to one embodiment, the inner peripheral surface of said outer shell corresponds to said outer surface of said volume of the wave guiding channel, for which the slope discontinuity zone formed by the inner vertices is replaced by a curved zone to obtain slope continuity of the inner peripheral surface, and the outer peripheral surface of said core corresponds to said inner surface of said volume of the wave guiding channel for which the slope discontinuity zone formed by the outer vertices is replaced by a curved zone to obtain slope continuity of the inner peripheral surface.

[0040] According to one embodiment, the upper opening angle, respectively the lower opening angle, is defined as a function of, is preferably equal to, the angle which forms an upper face, respectively a lower face, of the housing of the enclosure in which the waveguide device is intended to be housed, with the median plane of the housing of said enclosure which is orthogonal to the output face of the housing opposite which the output opening of the waveguide device is intended to be oriented.

[0041] According to one embodiment, the rectangular outlet surface is equal to or larger than the annular inlet surface.

[0042] According to one embodiment, the waveguide device being housed in an enclosure housing, the outlet opening has a height equal to at least 80% of the height of the outlet face of the enclosure housing.

[0043] According to one embodiment, the outer shell and the core are each produced by molding, preferably by plastic injection.

[0044] According to one embodiment, the upper opening angle and / or the lower opening angle has a value within the range [5°; 30°].

[0045] The invention also relates to a waveguide device, obtained by the method according to any one of the preceding embodiments.

[0046] The invention also relates to a waveguide device comprising: - an external peripheral wall, called the external shell, - an internal peripheral wall, called the core, surrounded by the external shell; the outer shell and the core delimiting between them: - an inlet opening which has an annular inlet surface, and to which an acoustic wave generator is capable of being connected, - an outlet opening, called a mouth, having a rectangular outlet surface, the outer diameter of the annular inlet opening being less than the length of the long side of the rectangle of the outlet opening, and being greater than half the length of the long side of the rectangle of the outlet opening, the set of two inlet and outlet surfaces having a plane of symmetry, called the vertical plane of symmetry, passing between the two large sides of the rectangle of the outlet surface, and a median plane, called the horizontal median plane, orthogonal to the vertical plane of symmetry, said planes passing through the center of the annular inlet surface and through the center of the rectangular outlet surface, - an acoustic waveguide channel communicating between the inlet opening and the outlet opening and defined between an inner peripheral surface of the outer shell and an outer peripheral surface of the core; characterized in that, for a portion, called the upper lateral portion, of the annular inlet surface, and a portion, called the upper lateral portion, of the outlet surface, defined by cutting the set of inlet and outlet surfaces along said vertical plane of symmetry and said horizontal median plane, said portion su lateral upper side being located on one side of the plane called the upper side and on one side of the plane, called the first lateral side; the path, called the first exterior path, for a first pair of points which comprises a first point of the exterior contour of the upper lateral portion of the entry surface located in the horizontal median plane, and a first point of the exterior contour of the upper lateral portion of the exit surface located in said horizontal median plane, has a length called the reference length; for a second pair of points comprising a second point of the outer contour of the upper lateral portion of the input surface, which belongs to the vertical plane of symmetry, and a second point of the outer contour of the upper lateral portion of the output surface (S9), which belongs to the vertical plane of symmetry; the second external path, in the vertical plane of symmetry, which connects said second point of the external contour of the upper lateral portion of the entry surface and said second point of the external contour of the upper lateral portion of the exit surface, comprises: - a first segment, called the opening segment, the majority of which belongs to the inner peripheral surface of the outer shell, and which is inclined at an angle of predefined value, called the upper opening angle, relative to the axis of intersection of the two planes with each other, and - a second segment, called the folding segment, the majority of which belongs to the inner peripheral surface of the outer shell, and which extends the first segment to said second point of the outer contour of the upper lateral portion of the entry surface, the length of said outer path being equal to said determined reference length, the junction point of the two segments being called the exterior vertex; for a plane, called the upper exterior vertex plane, passing through said exterior vertex and said first point of the exterior contour of the upper lateral portion of the output surface, and the center of the rectangular output surface; and, for several other pairs of intermediate points, located between the first and second pairs of points, each pair of intermediate points comprising a point of the outer contour of the first upper lateral portion of the entry surface and a corresponding point of the outer contour of the first upper lateral portion of the exit surface: considering the outer path, called the intermediate outer path, formed by an opening segment the majority of which belongs to the inner peripheral surface of the outer shell and a folding segment the majority of which belongs to the inner peripheral surface of the outer shell, and which connect said intermediate points of said pair of points, the junction point of said segments belonging to the plane of outer upper vertices, the length of said intermediate outer path is equal to said reference length; considering the path, called the first interior path, for a first pair of points which comprises a first point of the interior contour of the upper lateral portion of the entry surface located in the horizontal median plane, and a first point of the interior contour of the upper lateral portion of the exit surface located in said horizontal median plane; the length of said first interior path is equal to the reference length; the interior contour of the upper portion of the exit surface corresponding to the segment of the exit surface which extends in the vertical plane of symmetry and which results from the cutting of the exit surface according to said vertical plane of symmetry and said horizontal median plane; for a second pair of points comprising a second point of the inner contour of the upper lateral portion of the input surface (1), which belongs to the vertical plane of symmetry, and a second point of the inner contour of the upper lateral portion of the output surface, which belongs to the vertical plane of symmetry; considering the second interior path, in the vertical plane of symmetry, which connects said second point of the interior contour of the upper lateral portion of the entry surface and said second point of the interior contour of the upper lateral portion of the exit surface, the second interior path comprising: - a first segment, called the opening segment, the majority of which belongs to the outer peripheral surface of the core and which is inclined at said upper opening angle, relative to the axis of intersection of the two planes with each other, and - a second segment, called a folding segment, the majority of which belongs to the outer peripheral surface of the core and which extends the first segment up to said second point of the inner contour of the upper lateral portion of the entry surface, the junction point between straight lines passing through the two segments being called the inner vertex; the length of said second external path is equal to said reference length, for a plane, called the upper interior vertex plane, passing through said interior vertex and said first point of the interior contour of the upper lateral portion of the output surface, and the center of the rectangular output surface; and, for several other pairs of intermediate points, located between the first and second pairs of points, each pair of intermediate points comprising a point of the inner contour of the first upper lateral portion of the entry surface and a corresponding point of the inner contour of the first upper lateral portion of the exit surface: considering each interior path, called an intermediate interior path, which connects points of a pair of intermediate points, and which comprises a segment opening segment the majority of which belongs to the outer peripheral surface of the core and a folding segment the majority of which belongs to the outer peripheral surface of the core and which are defined so that the junction point of said segments belongs to the plane of inner upper vertices, each intermediate inner path has a length equal to the reference length dl9max.

[0047] According to one embodiment, the inner peripheral surface, and / or respectively the outer peripheral surface, comprises a circular arc portion which connects together the folding segment portions and the opening segment portions which belong to the inner peripheral surface, respectively to the outer peripheral surface, so that said segment portions are tangent to the corresponding circular arc.

[0048] According to one embodiment, the lengths of outer paths and inner paths associated with lower lateral portions of the inlet and outlet surfaces, located relative to said upper lateral portions on the other side of the horizontal median plane, are equal to said reference length.

[0049] According to one embodiment, the acoustic wave generator system is capable of being connected to the inlet opening of the outer shell, either directly or indirectly by a connection device whose inlet opening has a disc-shaped surface.

[0050] According to one embodiment, the internal volume of the connection device is defined between an internal cone connected to the core and an external truncated cone connected to the external shell.

[0051] According to one embodiment, the connection device has two internal surfaces which define between them a passage whose inlet is a disc-shaped surface and whose outlet is an annular-shaped surface connected to the inlet of the external shell, the two internal surfaces being configured so as not to introduce a difference in sound wave propagation time between the two internal surfaces (in other words configured to keep the acoustic waves in phase between the disc-shaped inlet of the connection device and the annular outlet of said connection device).

[0052] The invention also relates to an assembly of a waveguide device according to any one of the proposed embodiments, and an acoustic wave generator system.

[0053] The invention also relates to a method of manufacturing a waveguide comprising the following steps:

[0054] - acquisition of a set of computer data, preferably in the form of a computer file, representative of the external peripheral surface of the core and the internal peripheral surface of the external shell of the waveguide to be manufactured, said data set having been generated by implementing the steps of generating the external surface and the internal surface of the volume delimited by the waveguide channel proposed above. The external surface and the internal surface of the volume delimited by the waveguide channel are respectively representative of the internal peripheral surface of the external shell and the external peripheral surface of the core of the waveguide to be manufactured;

[0055] - manufacturing the outer shell so that the inner peripheral surface of said outer shell is defined in terms of said outer surface of said volume, and the outer peripheral surface of said core is defined in terms of said inner surface of said volume of the waveguide channel.

[0056] The file may comprise a set of points in space and / or plane data that define the outer peripheral surface of the core and the inner peripheral surface of the outer shell that correspond to the inner peripheral surfaces of the waveguide channel of the waveguide. The computer data set may be stored in a computer medium, such as a memory in a remotely accessible server or on a transportable memory such as a USB key or on any other computer medium.

[0057] Preferably, the manufacture of the outer shell comprises the manufacture of a first mold, for example for manufacturing two half-shells of the outer shell, and the first mold comprises a molding surface which is defined by or as a function of the external surface of the volume delimited by the waveguiding channel defined in the acquired computer data set. Advantageously, the manufacture of the core comprises the manufacture of a second mold, for example for manufacturing two half-shells of the core, and the second mold comprises a molding surface which is defined by or as a function of the internal surface of the volume delimited by the waveguiding channel defined in the acquired computer data set.

[0058] According to one embodiment, the outer shell is connected to the core by connecting elements, such as connecting tabs, also called spacers, which make it possible to keep the internal peripheral surface of the outer shell separated from the external peripheral surface of the core to obtain a relative positioning (arrangement) of said external and internal peripheral surfaces which corresponds to the relative positioning of the corresponding external and internal surfaces of the volume delimited by the waveguide generated and defined in said set of computer data.

[0059] The invention also relates to a computer program comprising program code instructions for executing the steps of generating the external surface and the internal surface of the volume delimited by the waveguiding channel proposed above, and preferably for executing the manufacturing of the external shell and the core as proposed above, for example by controlling a manufacturing machine. making a mold corresponding to the outer shell and a mold corresponding to the inner shell.

[0060] The steps may thus be carried out in the form of computer instructions executable by one or more computers. The computer programs, or computer instructions, may be contained in program storage devices, for example computer-readable digital data storage media, or executable programs. The programs or instructions may also be executed from program storage devices.

[0061] According to one embodiment, the computer system comprises a computer equipped with a screen, a user interface, such as a keyboard and mouse, and a computer-aided design program.

[0062] The invention also relates to an enclosure comprising a housing, and, housed in the housing, a waveguide device according to any one of the proposed embodiments and an acoustic wave generator system connected to the waveguide device.

[0063] According to one embodiment, the upper opening angle and / or the lower opening angle has a value within the range [5°; 30°].

[0064] The invention also relates to a set of stacked enclosures, each enclosure being in accordance with the embodiment proposed above, the enclosures being configured so that the acoustic waves emerging from said enclosures are in phase. Brief description of the drawings

[0065] Other characteristics and advantages of the invention will emerge from the following description, which is purely illustrative and non-limiting and must be read in conjunction with the appended drawings, in which:

[0066] - [Fig.l] [Fig.l] illustrates the constructive acoustic interference obtained with two enclosures each comprising a waveguide according to one embodiment of the invention;

[0067] - [Fig.2] [Fig.2] illustrates a perspective view of part of an enclosure comprising a housing housing an acoustic wave generator system and a waveguide according to one embodiment of the invention;

[0068] - [Fig.3] [Fig.3] illustrates a perspective view of the waveguide of [Fig.2], connected to the acoustic wave generator system, with one half-shell of the outer shell of the waveguide removed;

[0069] - [Fig.3A] [Fig.3A] illustrates a perspective view of the waveguide of [Fig.2], one half shell of the outer shell and one half shell of the core being removed;

[0070] - [Fig.3B] [Fig.3B] illustrates a perspective view of the waveguide of [Fig.2], connected to the acoustic wave generator system, the other half-shell of the hull outer and the other half-shell of the waveguide core being removed, compared with the view of [Fig.3A].

[0071] - [Fig.3C] [Fig.3C] repeat [Fig.3A] to illustrate parts of segments opening and folding which belong to the outer and inner peripheral surfaces of the waveguide and which are connected to each other by an arcuate part according to one embodiment of the invention,

[0072] - [Fig.4] [Fig.4] illustrates a perspective and axial sectional view along a plane of vertical symmetry, of a waveguide according to an embodiment of the invention, which may be that of [Fig.2], the section showing a device for connecting an acoustic wave generator to the annular input of the waveguide;

[0073] - [Fig.5] is a step of a method of manufacturing a waveguide according to a mode of carrying out the invention;

[0074] - [Fig.6] is another step of a method of manufacturing a waveguide according to a embodiment of the invention;

[0075] - [Fig.7] is another step of a method of manufacturing a waveguide according to a embodiment of the invention;

[0076] - [Fig.8] is another step of a method of manufacturing a waveguide according to a embodiment of the invention;

[0077] - [Fig.9] is a step of a method of manufacturing a waveguide according to a mode of carrying out the invention;

[0078] - [Fig. 10] is another step of a method of manufacturing a waveguide according to an embodiment of the invention;

[0079] - [Fig. 11] is another step of a method of manufacturing a waveguide according to an embodiment of the invention;

[0080] - [Fig. 12] is a 3D view of surfaces of the volume of the waveguide channel obtained by a method of manufacturing a waveguide according to an embodiment of the invention;

[0081] - [Fig.13] is another step of a method of manufacturing a waveguide according to an embodiment of the invention, in particular when the median plane is not a plane of symmetry;

[0082] - [Fig. 14] is another step of a method of manufacturing a waveguide according to an embodiment of the invention which follows the step illustrated in [Fig. 13];

[0083] - [Fig. 15] is a 3D view of one half of the surfaces of the guide channel volume waves obtained by a method of manufacturing a waveguide according to an embodiment of the invention;

[0084] - [Fig. 16] is a 3D view of the other half of the surfaces of the volume of the channel of wave guidance obtained by symmetry of the surfaces of [Fig. 15] by a vertical plane of symmetry.

[0085] In particular, Figures 5 to [Fig. 16] are views of different steps or their result which make it possible to generate the geometric surfaces which connect the input and output surfaces of the waveguide together and which delimit between them the volume of the waveguide channel through which the waves propagate between the input and the output of the waveguide. DETAILED DESCRIPTION

[0086] Embodiments of the invention are described below with reference to the accompanying drawings. Like numerals refer to like elements throughout the drawings. However, this inventive concept may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. The scope of the invention is defined by the appended claims.

[0087] A reference throughout the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, the occurrence of the phrase "in an embodiment" at various locations throughout the specification does not necessarily refer to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0088] With reference to the figures, a waveguide device, called a waveguide 100, is shown, which makes it possible to control the directivity of one or more sound sources of an acoustic wave generator system SG. The sound sources are also called transducers or loudspeakers. The waveguide device 100 is intended to be housed in a housing 10 of an enclosure 1 while being connected to the acoustic wave generator system SG.

[0089] The waveguide 100 defines a channel for the passage of acoustic waves.

[0090] The proposed waveguide makes it possible to maintain the acoustic waves in phase between the input surface and the output surface. In other words, the waveguide makes it possible not to introduce a delay gradient whatever the path of the wave between the input and output surfaces.

[0091] [Fig.l] illustrates the constructive acoustic interference (summation) that is obtained with two enclosures 1,1' each comprising a waveguide 100, 100' according to an embodiment of the invention.

[0092] The acoustic enclosures 1,1' are juxtaposed and, thanks to the absence of a delay gradient at the level of the waveguides 100, 100', the acoustic wavefronts FOI, FOI' at the output of the waveguides 100, 100' are in phase, which makes it possible to generate constructive acoustic interference (summation) IC. This results in greater energy in the radiating space of the speakers, which increases the acoustic range.

[0093] A method of constructing the waveguide is proposed in which equality of paths is sought geometrically for the paths traveled by the acoustic waves between the input and output surfaces of the waveguide. The manufacturing of the waveguide includes a computer-implemented geometric surface generation phase which makes it possible to define the peripheral surfaces of the volume (passage or air volume) delimited by the channel of the waveguide through which the acoustic waves are intended to propagate and which connect the input and output surfaces of the waveguide to each other. These peripheral surfaces of the volume of the guide channel make it possible to define the corresponding internal surfaces of the waveguide which physically delimit the waveguide channel which guides the waves between the input opening and the output opening of the waveguide.

[0094] As detailed below, these internal surfaces correspond respectively to the internal peripheral surface of a shell called the external shell, and to the external peripheral surface of a core called the internal core, surrounded by said internal peripheral surface of the external shell.

[0095] The proposed construction method makes it possible to quickly and reliably generate the peripheral surfaces of the volume delimited by the waveguide channel for a given input surface and output surface, so as to be able to manufacture, from these generated surfaces, a waveguide having a waveguiding channel by means of which the acoustic waves are kept in phase between the input surface and the output surface of the waveguide. The propagation speed of the sound wave is considered the same for all points on the input surface of the waveguide.

[0096] In other words, the design phase implemented by computer makes it possible to generate surfaces delimiting between them an air passage corresponding to the passage delimited by the channel for guiding the acoustic waves that it is desired to obtain for the waveguide to be manufactured. The design phase thus makes it possible to obtain a set of computer data, for example in the form of a computer file, comprising the geometric data representing the internal surfaces of the channel intended to guide the waves which pass through the channel.

[0097] Waveguide device 100

[0098] The waveguide device 100 is in the form of a solid body which comprises: - an external peripheral wall CQE, called external shell. The external shell CQE has an internal peripheral surface SPI which corresponds to, or is defined from, an external peripheral surface SFEXTVAC generated according to the detailed method hereinafter, - an internal peripheral wall NYI, called core, surrounded by the external shell CQE. The core NYI has an external peripheral surface SPE which corresponds to, or is defined from, an internal peripheral surface SFINTVAC generated according to the method detailed below.

[0099] The external shell CQE and the core NYI delimit between them:

[0100] - an inlet opening 110, called a groove, which has an annular surface SI, and to which an SG acoustic wave generator system is capable of being connected directly or indirectly as explained below;

[0101] - an outlet opening 190, called a mouth, preferably of a height substantially equal to the height of the enclosure, which has a rectangular-shaped S9 output surface, and

[0102] - an acoustic wave guiding channel CNL1 communicating between the opening inlet 110 and outlet opening 190, the guide channel CNL1 being defined between the inner peripheral surface SPI of the outer shell CQE and the outer peripheral surface of the core NYI.

[0103] The outer diameter of the annular inlet opening 110 is less than the length of the long side (height) of the rectangle of the outlet opening 190, and is greater than half the length of the long side (half the height) of the rectangle of the outlet opening 190.

[0104] SG system of acoustic wave generator

[0105] The acoustic wave generator system SG may comprise a generator G1 of acoustic waves in the high frequencies, also called a treble generator. The acoustic wave generator system SG may further comprise a generator G2 of acoustic waves in the medium frequencies, also called a medium generator.

[0106] According to one embodiment, and as for example illustrated in [Fig.3A] or 4, the output of the generator G1 is connected to the input of the waveguide 100, via a CAI connection device.

[0107] The CAI connection device comprises: - an external peripheral wall CAE1 formed by a truncated cone, preferably provided on the side of its large base with a collar CJ for junction with the external shell CQE, and - an inner peripheral wall CAI1 formed by a cone whose apex STCAI1 is centered on the disk surface SDCAE1 which forms the entrance (small section) of the outer peripheral wall truncated cone CAE1.

[0108] The entrance of the truncated cone defines a disc entrance surface and the apex of the internal cone is centered on the disc.

[0109] Such a design of the CAI connection device makes it possible to generate a connection channel between the output of the generator G1 and the annular input of the channel CNL1. waveguide waveguide, keeping the acoustic waves from generator G1 in phase until they reach the annular input of the waveguide which itself keeps the waves in phase until they reach the output opening.

[0110] When present, the acoustic wave generator G2 may be of the electrodynamic type. The generator G2 may comprise a coil (not shown) fixed to the outer peripheral wall CAE1 of the connecting device CAI and a magnet (not shown) making it possible to exert a force with the coil on the outer peripheral wall CAE1 to make it vibrate and thus generate medium-frequency acoustic waves which then propagate in the channel CNL1 of the waveguide. In this case, the outer peripheral wall CAE1 of the connecting device CAI forms a part of the generator G2. The generator G1 and the generator G2 are thus arranged in a so-called coaxial configuration.

[0111] The enclosure 1 may also comprise at least one HPG bass speaker. In particular, HPG bass speakers may be arranged on either side of the waveguide 100, as for example illustrated in [Fig.2].

[0112] The internal peripheral surface SPI of the external shell CQE and the external peripheral surface SPE of the core NYI delimit between them a communication passage which forms the channel CNL1 for guiding the waves from the inlet opening 110 (whose surface SI is annular) to the outlet opening 190 (whose surface S9 is rectangular).

[0113] The internal peripheral surface SPI of the external shell CQE and the external peripheral surface SPE of the core NYI each have a particular geometry which is defined, as detailed below, according to predefined data which include: - the annular SI input surface, - the rectangular S9 output surface, - as well as a higher opening angle aouvsup; - and, when the median plane PN2, which passes through the center 01 of the annular surface SI and the midpoints of the two large sides of the rectangle of the exit surface S9, is not a plane of symmetry: an opening angle less than or equal to, as explained below.

[0114] When the plane PN2 is a plane of symmetry, the lower opening angle aouvinfest has the same value as the upper opening angle aouvsup.

[0115] Geometry of the volume delimited by the waveguide channel

[0116] The annular input opening 110 of the waveguide has an annular input surface SI (example illustrated in particular in Figures 3A, 11 and 12). The annular input surface SI is defined between an outer contour CEI and an inner contour Cil ([Fig.12]).

[0117] The rectangular output opening 190 of the waveguide has a rectangular output surface S9 (example illustrated in particular in [Fig.3], 11 and 12).

[0118] As explained above for the inlet 110 and outlet 190 openings, the outer diameter of the annular inlet surface S1 is less than the length of the long side (height) of the rectangle of the outlet surface S9, and is greater than half the length of the long side (half-height) of the rectangle of the outlet surface S9.

[0119] The annular inlet surface SI and the rectangular outlet surface S9 form a set of surfaces which has a first plane of symmetry PN1. The rectangular outlet surface S9 is defined by an outer contour CE9. To facilitate the design of the geometric surfaces of the acoustic wave passage volume delimited by the guide channel of the waveguide and as detailed below, the outlet surface S9 (and the inlet surface SI) is cut by a plane of symmetry PN1 (parallel to its longest side), and the intersection of the outlet surface S9 with the plane of symmetry PN1 defines a segment called the inner contour CI9 ([Fig. 12]).

[0120] Said first plane of symmetry PN1 is said to be vertical because in the configuration of use of the enclosure 1 in which the waveguide 100 is housed, said plane of symmetry PN1 is vertical. In particular, the length (also called height or long side) of the rectangle of the output surface S9 is oriented vertically.

[0121] A second plane PN2, called the horizontal median plane, is defined for the set of surfaces SI, S9, which passes through the center 01 of the surface SI and through the center 09 of the surface S9 and which is perpendicular to the vertical plane of symmetry PN1. According to one embodiment and as explained below, it can be provided that the horizontal median plane PN2 is also a plane of symmetry for the set of surfaces SI, S9.

[0122] The dimensions of the annular inlet opening 110 and the rectangular outlet opening 190 (and therefore the corresponding surfaces S1 and S9), and their arrangement relative to each other, are provided data, which are preferably predefined according to the characteristics of the enclosure 1 in which the waveguide device 100 is intended to be housed.

[0123] The outer contour of the annular inlet surface SI corresponds to the contour of the inner peripheral surface SPI of the outer shell CQE at the inlet opening 110, i.e. the outer contour of the ring of the annular inlet opening 110, and the inner contour of the annular inlet surface SI corresponds to the contour of the outer peripheral surface SPE of the core NYI at the inlet opening 110, i.e. the inner contour of the ring of the annular inlet opening 110. Similarly, the outer contour of the rectangular outlet surface S9 corresponds to the contour of the inner peripheral surface SPI of the outer shell CQE at the outlet opening 190 - i.e. the inner contour of the opening 190. As explained below, the so-called inner contour of the rectangular outlet surface S9 corresponds to the segment of the exit surface S9 which extends in the plane PN1 and which results from the cutting of the exit surface S9 with the plane PN1.

[0124] Cutting of all the input surfaces SI and output S9

[0125] To facilitate the design of the geometric surfaces SFEXTVAC, and SFINTVAC of the volume delimited by the wave channel CNL1 from which the physical peripheral surfaces SPE, SPI of the wave channel are produced, the set of input and output surfaces SI, S9 is cut by the planes PN1, PN2.

[0126] The cutting of the entry surface SI by the plane PN1 and by the plane PN2 provides a first upper lateral portion PSlsup of the entry surface SI ([Fig.5]). The upper lateral portion PSlsup is located on one side of the plane PN2, called the upper side, and on one side of the plane PN1 called the first lateral side. We can also define a lower lateral portion PSlinf (Figures 11 and 13) which is located on the side of the plane PN2, called the lower side, opposite the upper side, and which is also located on the side of the plane PN1 which is said first lateral side. The other portions of the surface SI correspond to the portions obtained by symmetry by the plane PN1 of said portions PSlsup and PSlinf.

[0127] The upper lateral portion PSlsup has an outer contour PCESlsup and an inner contour PCISlsup. The inner contour PCISlsup corresponds to the arc of the portion PSlsup closest to the center 01 of the input surface SI, and the outer contour PCESlsup corresponds to the arc of the portion PSlsup furthest from the center 01 of the input surface SL

[0128] The cutting of the exit surface S9 by the plane PN1 and by the plane PN2 provides, in a similar manner to what has been described for the entry surface SI, a first upper lateral portion PS9sup of the exit surface S9 (located on the same side of the planes PN1 and PN2 as the portion PSlsup) which has an outer contour PCES9sup and a so-called inner contour PCIS9sup. The inner contour PCIS9sup corresponds to the segment of the portion PS9sup of the exit surface S9 which is located in the plane PN1. The outer contour PCES9sup of the portion PS9sup is the contour of the portion PS9sup which is part of the (implicitly outer) contour of the rectangular surface S9.

[0129] Said upper lateral portions PSlsup and PS9sup of the inlet and outlet surfaces are located opposite each other.

[0130] We thus obtain by cutting along the planes PN1, PN2 a first upper lateral quarter of the set of surfaces SI, S9. As detailed below, we seek to determine for this first quarter an external surface SFEXTsup, respectively internal SFINTsup ([Fig. 10]), which connects the external contours, respectively internal, of said surface portions PSlsup PS9sup. Said external surface, respectively internal, corresponds to the set of paths traveled by the acoustic waves between the external contour, respectively internal, of the inlet opening and the outer contour, respectively inner, of the output opening, for the part of the waveguide channel corresponding to this first quarter, with the constraint that said paths must be of the same length so as not to introduce phase shift between the waves. As detailed below, the outer surface SFEXTsup, respectively inner SFINTsup, makes it possible to manufacture the surface SPIsup of the outer shell CQE of the waveguide, respectively the surface SPEsup of the core NYI of the waveguide ([Fig.3B]).

[0131] The outer and inner surfaces SFEXTinf, SFINTinf of the volume part of the guide channel ([Fig. 15]) corresponding to the lower lateral quarter of the surface assembly SI, S9 located on the other side of the plane PN2, can, when the plane PN2 is a plane of symmetry, be obtained by symmetry, according to said plane PN2, of the outer and inner surfaces SFEXTsup, SFINTsup. When said plane PN2 is not a plane of symmetry, the outer and inner surfaces SFEXTinf, SFINTinf can be obtained by repeating the operations which are presented below to obtain the surfaces SFEXTsup, SFINTsup, by applying them to the corresponding portions PSlinf and PS9inf of the surfaces SI and S9 and by using a lower opening angle value a ouvjnf given in place of the upper opening angle value aouv sup used to obtain the surfaces SFEXTsup, SFINTsup.

[0132] The outer and inner surfaces SFEXT'sup, SFINT'sup of the part of the volume of the guide channel corresponding to the other upper lateral quarter of the surface assembly SI, S9 located on the other side of the plane PN1, can be obtained by symmetry, according to said plane PN1, of the outer and inner surfaces SFEXTsup, SFINTsup ( [Fig.16]).

[0133] Similarly, the outer and inner surfaces SFEXT'inf, SFINT'inf of the volume part of the guide channel corresponding to the other lower quarter of the surface assembly SI, S9 located on the other side of the plane PN1, can be obtained by symmetry, according to said plane PN1, of the outer and inner surfaces SFEXTinf, SFINTinf.

[0134] Determination of the distance dl9max

[0135] As illustrated in the example of [Fig.7], in the median plane PN2, the distance, called the maximum distance or reference length dl9max, is determined between a point P1ES1, which belongs to the plane PN2, of the outer contour PCESlsup of the portion PSlsup of the input surface SI, and a point P1ES9, which belongs to the plane PN2, of the outer contour PCES9sup of the portion PS9sup of the output surface S9. In other words, the length of the path traveled by a sound wave in a straight line between the point P1ES1 and the point P1ES9 is determined.

[0136] Path connecting points P2ES1 and P2ES9 in plane PN1

[0137] As illustrated in the example of [Fig.7], in the plane of symmetry PN1, for a point P2ES1, called the upper end point, which belongs to the outer contour PCESlsup and to the plane PN1, and, in the plane of symmetry PN1, for a second point P2ES9, called the upper end point, which belongs to the outer contour PCES9sup and to the plane PN1, a path is also determined in said plane PN1 between the two upper end points P2ES1 and P2ES9 which has the following characteristics:

[0138] - the path length is equal to the maximum distance dl9max (length of reference);

[0139] - the path comprises two segments SDE2, SRE2, and the segment SDE2, called opening segment, which arrives at the exit surface S9, is inclined with respect to the axis A12 of intersection of the planes PN1 and PN2, by an angle equal to the predefined upper opening angle aouvsupréférent.

[0140] The upper opening angle aouv supest is an input data that is provided.

[0141] For a given acoustic energy supplied at the input of the waveguide by the SG generator system, the larger the upper (and / or lower) opening angle, the smaller the acoustic range, and, conversely, the smaller the upper (and / or lower) opening angle, the larger the acoustic range. However, it is understood that the larger the range, the greater the level of acoustic energy near the speaker and the potential for disturbance for a user located nearby. Range is understood to mean the distance from which a sound emitted by the speaker or the speaker system is no longer perceptible to the listener.

[0142] According to one embodiment of the invention and as for example illustrated in [Fig.l], the value of the upper opening angle can be defined as being equal to the angle formed by the upper face 11 of the housing 10 of the enclosure 1 with the median plane of the housing 10 of the enclosure 1 which is a plane which passes between the upper 11 and lower 12 faces of the housing 10 of the enclosure 1 and which is perpendicular to the front face 13 (output face) of the enclosure (towards which the output 190 of the waveguide 100 is oriented).

[0143] The upper, respectively lower, opening angle may also correspond to the maximum upper, respectively lower, half-angle of articulation (around a horizontal axis) that the housing 10 (external envelope) of the acoustic enclosure 1 allows in relation to a juxtaposed neighboring enclosure, in particular to satisfy the need of the intended application (i.e. according to the desired range of the enclosure assembly used in sound reinforcement).

[0144] The right segment SRE2, called the folding segment, extends the segment SDE2 to the point P2ES1. The length of the path formed by the addition of the length of the segment SDE2 and the length of the segment SRE2 is equal to said determined maximum distance dl9max. It is understood that the fixing of a given length (dl9max) for the length of the path formed by the sum of the lengths of the segments SDE2 and SRE2, and fixing a given upper opening angle aouv sup, defines the position of the junction point between the two segments SDE2, SRE2. This junction point is called the outer vertex STE2. The angle formed between the folding segment SRE2 and the axis A12 is called the upper folding angle.

[0145] PSSE exterior upper summit plan

[0146] As illustrated in [Fig.7], the previously defined outer vertex STE2 is used to define a plane, called the outer upper vertex plane PSSE, which passes through the point STE2, the point P1ES9 and the point 09, called the geometry origin point, of the upper portion PS9sup of the output surface S9 which results from the intersection of the planes PN1, PN2, with the output surface S9. The point 09 corresponds to the center of the surface S9. The point 09 also corresponds to the lower end point P1IS9 of the inner contour PCIS9.

[0147] Generation of the outer upper vertices

[0148] The construction of a path formed by a first segment (folding segment) and a second segment (opening segment) between two points of a pair of points formed by a point of the outer contour PCESlsup of the upper portion PSlsup of the input surface SI and a corresponding point of the outer contour PCES9sup of the upper portion PS9sup of the output surface S9, is carried out for several other pairs of points PiESl, PiES9 to obtain the folding segment SREi and the opening segment SDEi (i being an index varying from 3 to N, with N an integer greater than or equal to 3 corresponding to the number of sampling points of the outer contour PCES9sup and of the outer contour PCESlsup that is desired), with the following constraints: - the total length of the path formed by the two segments SREi, SDEi, must be equal to the maximum determined length dl9max, - the junction point STEi, called the exterior vertex, of the segments SREi, SDEi belongs to the plane PSSE.

[0149] Thus, as shown in [Fig.8], we can define N-2 pairs of intermediate points (located between the previous pairs of points P1ES1, P1ES9 and P2ES1, P2ES9), each pair of points comprising a point PiESl of the upper outer contour of the input surface SI and a corresponding point PiES9 of the upper outer contour of the output surface S9, with i an index ranging from 3 to N, such that the ratio of the distance between the point PiESl and the point PiESl to the length of the outer contour PCESlsup of the upper portion PSlsup of the input surface is equal to the ratio of the distance between the point PiES9 and the point P1ES9 to the length of the outer contour PCES9sup of the upper portion PS9sup of the output surface S9. In the example of [Fig.9], we took N = 10 so that eight intermediate paths were determined. We can of course plan to increase the number N for better precision of the surface to be defined from said paths.

[0150] We thus determine for each pair of points PiESl, PiES9, the path, also called the intermediate exterior path, formed by the segments SREi and SDEi which connect the points PiESl and PiES9, with a junction point between said segments, noted STEi, which is the upper exterior vertex of the path, and which is defined as belonging to the plane of upper exterior vertices PSSE, the length of said path being equal to the reference length dl9max.

[0151] Outer surface of the first upper lateral quarter of the volume of the communication passage of the guide channel

[0152] The outer paths obtained as explained previously from the upper portion PSlsup of the inlet surface SI and the upper portion PS9sup of the outlet surface S9 are used to generate an outer upper surface SFEXTsup ([Fig.10]). It may be provided that the surface parts which extend between two outer paths have a curvature on the inlet opening side which corresponds to the curvature of the portion of the contour of the annular opening which connects the two outer paths together. Advantageously, this curvature is modified along the paths until a flat surface is reached to arrive at the portion of the contour of the rectangular outlet opening which connects the two outer paths together on the outlet side. It may also be provided to round off the vertex area between each opening segment and the corresponding folding segment to obtain slope continuity in this vertex area.

[0153] It is understood that, for the production of the internal solid surfaces of the waveguide channel, the angular zones of the generated geometric surfaces, from which the internal solid surfaces of the waveguide channel are manufactured, preferably molded, can be replaced by zones in an arc of a circle, while maintaining an equal length between the different corresponding paths.

[0154] Interior vertex plan

[0155] In the median plane PN2, the distance between a point P1IS1, which belongs to the plane PN2, of the outer contour PCISlsup of the portion PSlsup of the input surface and a point P1IS9, which belongs to the plane PN2, of the inner contour PCIS9sup of the portion PS9sup of the output surface is equal to the maximum distance (reference length) dl9max previously determined between the points PiESl and P1ES9.

[0156] Path connecting points P2ES1 and P2ES9 in plane PN2

[0157] As illustrated in the example of [Fig.9], in the plane of symmetry PN1, for a point P2IS1, called the upper end point, which belongs to the inner contour PCISlsup and to the plane PN1, and, in the plane of symmetry PN1, for a point P2IS9, called the upper point, which belongs to the inner contour PCIS9sup and to the plane PN1, and which is separated from point P2ES9 by a distance equal to the spacing between point P2ES1 and P2IS1, a path is also determined in said plane PN1 between the two upper end points P2IS1 and P2IS9 which has the following characteristics: - the length of the path is equal to the reference length dl9max; - the path includes a folding segment SRI2 and an opening segment SDI2 (which arrives at the exit surface S9): the opening segment is inclined relative to the axis A12 of intersection of the planes PN1 and PN2, by an angle equal to the predefined upper opening angle aouv_sup.

[0158] The segment SRI2 extends the segment SDI2 to the point P2IS1. The length of the path formed by the addition of the length of the segment SDI2 and the length of the segment SRI2 is equal to said determined maximum distance dl9max. It is understood that the fixing of a given length (dl9max) for the length of the path formed by the sum of the lengths of the segments SDI2 and SRI2, and the fixing of a given upper opening angle, defines the position of the junction point between the two segments. This junction point is called the inner vertex STI2. The angle formed between the folding segment SRI2 and the axis A12 is called the upper folding angle.

[0159] Interior upper summit plan

[0160] The previously defined interior vertex STI2 is used to define a plane, called the interior upper vertex plane (not shown), which passes through the point STI2, the point P1ES9 and the point 09, called the geometry origin point, of the upper portion PS9sup of the output surface S9 which results from the intersection of the planes PN1, PN2, with the output surface S9. As a reminder, the point 09 corresponds to the center of the surface S9 and also corresponds to the lower end point P1IS9 of the interior contour PCIS9.

[0161] Generation of interior upper vertices

[0162] The construction of a path formed by a first segment (folding segment) and a second segment (opening segment) between two points of a pair of points formed by a point of the inner contour PCISlsup of the upper portion PSlsup of the input surface SI and a corresponding point of the inner contour PCIS9sup of the upper portion PS9sup of the output surface S9, is carried out for several other pairs of points PilS 1, PiIS9 to obtain the folding segment SRIi and the opening segment SDIi (i being an index varying from 3 to N, with N an integer greater than or equal to 3 corresponding to the number of sampling points of the inner contour PCIS9sup and of the inner contour PCISlsup that is desired), with the following constraints: - the total length of the path formed by the two segments SRIi, SDIi, must be equal to the maximum determined length dl9max, - the junction point STIi, called the interior vertex, of the segments SRIi, SDIi belongs to said plane of interior upper vertices.

[0163] Thus, as shown in [Fig. 9], we can define N-2 pairs of intermediate points (located between the previous pairs of points P1IS1, P1IS9 and P2IS1, P2IS9), each pair of points comprising a point PilS 1 of the upper inner contour of the input surface SI and a corresponding point PiIS9 of the upper inner contour of the output surface S9, for i ranging from 3 to N, such that the ratio of the distance between the point PilSl and the point P1IS1 to the length of the inner contour PCISlsup of the upper portion PSlsup of the input surface, is equal to the ratio of the distance between the point PiIS9 and the point P1IS9 to the length of the inner contour PCIS9sup of the upper portion PS9sup of the output surface S9. In the example of [Fig. 9], we took N = 10 so that eight intermediate paths were determined.We can of course plan to increase the number N for better precision of the surface to be defined from said paths.

[0164] We thus determine for each pair of points PilS 1, PiIS9, the path formed by the segments SRIi and SDIi which connect the points PilSl and PiIS9, with a junction point between said segments, noted STIi, which is the upper interior vertex of the path, and which is defined as belonging to the plane of upper interior vertices, the length of said path being equal to the maximum length dl9max.

[0165] In other words, and as illustrated in [Fig.9], the steps which made it possible to determine the plane of exterior vertices PSSE and the corresponding exterior paths for pairs of exterior contour points are repeated with pairs of points of the interior contour PCISlsup of the first upper portion PSlsup of the input surface SI and of the interior contour PCIS9sup of the first upper portion PS9sup of the output surface S9, to obtain so-called interior paths formed between the points PilS 1 and PiIS9 of interior upper vertices STIi. The steps described previously for determining exterior paths can thus be repeated with, instead of the exterior contour, the interior contour PCIS1 of the upper portion PSlsup of the input surface SI and, instead of the exterior contour, the interior contour PCIS9 of the first lateral upper portion PS9sup of the output surface S9, to generate interior paths.

[0166] Inner surface of the first upper lateral quarter of the volume of the guide channel

[0167] Similarly to the generation of the outer upper surface SFEXTsup previously described, the inner paths obtained for the upper portions of the input surface PSlsup and the output surface PS9sup are used to generate an inner upper surface SFINTsup ([Fig. 10]) which passes through said inner paths and which connect together the inner contours of the input surface PSlsup and of the PS9sup output surface.

[0168] Provision may be made for the surface portions extending between two interior paths to have a curvature on the inlet opening side that corresponds to the curvature of the portion of the contour of the annular opening that connects the two interior paths together. Advantageously, this curvature is modified along the interior paths until a flat surface is reached to arrive at the portion of the contour of the rectangular outlet opening that connects the two interior paths together on the outlet side. Provision may also be made to round off the apex area between each opening segment and the corresponding folding segment to obtain slope continuity in this apex area.

[0169] The space delimited between said outer upper surface SFEXTsup and said inner upper surface SFINTsup forms a part of the inner space of the channel (passage for acoustic waves), corresponding to said first lateral upper quarter, which communicates with the inlet opening and the outlet opening of the waveguide device.

[0170] Lower lateral portion of the air volume of the guide channel

[0171] When the median plane PN2 is a plane of symmetry, a symmetry is applied by said plane PN2 to the whole of the outer upper surface SFEXTsup and the inner upper surface SFINTsup to obtain the outer lower surface SFEXTinf and the inner lower surface SFINTinf.

[0172] As for example illustrated in [Fig.13], when the median plane PN2 is not a plane of symmetry, the steps described previously which made it possible to obtain the outer upper surface SFEXTsup and the inner upper surface SFINTsup, are repeated with the whole of the inlet surface portion PSlinf and the outlet surface portion PS9inf which result from the section by the planes PN1 and PN2 of the whole of the inlet surfaces SI and outlet S9, said set of portions PSlinf, PS9inf being located, relative to the plane PN2, on the opposite side and opposite the set of portions PSlsup, PS9sup. Said repetition of the steps is carried out by replacing the upper opening angle aouvsup with a predefined lower opening angle aouvinf to determine the external paths SDEiinf, SREiinf of vertices STEiinf (as for example illustrated in [Fig.14]), as well as the corresponding interior paths (not shown), and obtain the corresponding exterior lower surface SFEXTinf and interior lower surface SFINTinf ([Fig. 15]).

[0173] Obtaining the total exterior surface area and the total interior surface area

[0174] We then apply a symmetry, by the vertical plane of symmetry PN1, to the set of the outer upper surface SFEXTsup, the inner upper surface SFINTsup, the outer upper surface SFEXTinf and the inner upper surface SFINTinf ([Fig. 15]), to obtain the outer upper surface SFEXT'sup, the inner upper surface SFINT'sup, the outer upper surface SFEXT'inf and the inner upper surface SFINT'inf ([Fig. 16]).

[0175] The external surfaces SFEXTsup, SFEXTinf, SFEXT'inf and SFEXT'sup which are joined form the total external surface SFEXTVAC (Figures 11 and 12) of the volume VACNL1 delimited by the guide channel of the waveguide.

[0176] The interior surfaces SFINTsup, SFINTinf, SFINT'inf and SFINT'sup which are contiguous form the total interior surface SFINTVAC ([Fig. 11]) of the volume VACNL1 delimited by the guide channel of the waveguide.

[0177] A set of surfaces is thus obtained, for example illustrated in [Fig. 12], which correspond to or from which can be manufactured the internal surfaces of the wave guide channel which connect the input surfaces SI and output surfaces S9 together so as to keep the acoustic waves in phase between the input and the output of the guide channel.

[0178] Manufacture of the outer shell and core

[0179] The outer shell CQE can then be manufactured such that the inner peripheral surface SPI of its peripheral wall, which faces the core NYI, is defined by or as a function of the total outer surface SFEXTVAC. Similarly, the core NYI can be manufactured such that the outer peripheral surface SPE of its peripheral wall, which is surrounded by the outer shell, is defined by or as a function of the total outer surface SFINTVAC.

[0180] In other words, the manufacturing of the outer shell CQE is carried out so that the internal peripheral surface SPI of said outer shell CQE is defined as a function of the jointed set of said outer surfaces SFEXTsup, SFEXTinf, SFEXT'sup, SFEXT'inf; and the manufacturing of the core NYI is carried out so that the external peripheral surface SPE of the core NYI is defined as a function of the jointed set of said inner surfaces SFINTsup, SFINTinf, SFINT'sup and SFINT'inf.

[0181] As illustrated in Figures 3, 3A, and 3B, in connection with Figures 15 and 16, the internal peripheral surface SPI of said external shell CQE comprises: - a lateral upper part SPIsup which is defined from the surface SFEXTsup, - another upper lateral part SPI'sup, symmetrical by the plane PN1, of the upper lateral part SPIsup, which is defined from the surface SFEXT'sup, - a lower lateral part SPIinf which is defined from the surface SFEXTinf, - another lower lateral part SPI'inf, symmetrical by the plane PN1, of the lower lateral part SPIinf, which is defined from the surface SFEXT'inf,

[0182] Similarly, the inner peripheral surface SPE of the NYI core comprises: - a lateral upper part SPEsup which is defined from the surface SFINTsup,

[0183]

[0184]

[0185]

[0186]

[0187]

[0188]

[0189]

[0190]

[0191]

[0192] - another upper lateral part SPE'sup, symmetrical by the plane PN1, of the upper lateral part SPEsup, which is defined from the surface SFINT'sup, - a lower lateral part SPEinf which is defined from the surface SFINTinf, - another lower lateral part SPE'inf, symmetrical by the plane PN1, of the lower lateral part SPEinf, which is defined from the surface SFINT'inf. [Fig.3] shows an upper lateral part SPEsup and a lower lateral part SPEinf of the NYI core, as well as an upper lateral part SPI'sup and a lower lateral part SPIinf of the external shell CQE. [Fig.3A] shows the other upper lateral part SPE'sup and the other lower lateral part SPE'inf of the NYI core, which are symmetrical, by the vertical PN1 symmetry plane, to the upper lateral part SPEsup and the lower lateral part SPEinf. Also visible are the upper lateral part SPI'sup and the lower lateral part SPI'inf of the external shell CQE already visible in [Fig.3]. [Fig.3B] shows the upper lateral part SPEsup and the lower lateral part SPEinf of the NYI core, as well as the upper lateral part SPISUp and the lower lateral part SPIinf of the external shell CQE. The parts SPEsup, SPEinf; SPIsup and SPIinf are respectively symmetrical by the vertical PN1 symmetry plane of the parts SPE'sup, SPE'inf; SPI'sup and SPI'inf. As illustrated more particularly in Figures 3A and 3B, the waveguide comprises connecting elements called PLI legs which make it possible to maintain the core and the outer shell in a given relative position corresponding to the desired waveguiding channel defined between said outer shell and the core. The waveguide thus manufactured is connected to an acoustic wave generation system SG as explained above, possibly via the intermediate connecting piece CAL. The entire waveguide and the acoustic wave generation system SG is housed in an enclosure, preferably with one or more bass speakers. According to one embodiment, the external shell CQE and the core NYI are each produced by molding, preferably by plastic injection. The CQE shell can be made in the form of two half-shells assembled together. The half-shells are obtained by manufacturing molds whose molding faces are made according to the defined SFEXTVAC surface. The NYI core can be made in the form of two half-shells assembled together. The half-shells are obtained by manufacturing molds whose molding faces are made according to the defined SFINTVAC surface. It is possible to provide for the production of a plurality of enclosures as described above and to superimpose them. Said enclosures are preferably articulated with each other. According to one embodiment, it is possible to implement a method of fa- construction of a waveguide which includes the following steps:

[0193] - acquisition of a computer data set defining a geo surface external metric SFEXTVAC1 and an internal geometric surface SFINTVAC1 of the air volume delimited by a waveguide channel CNL1, as previously described;

[0194] - manufacturing the waveguide device by manufacturing the external shell CQE so that the internal peripheral surface SPI of said external shell corresponds to said external surface SFEXTVAC of said volume of air delimited by the waveguiding channel, defined in the computer data set (the contiguous set of surfaces SFEXTsup, SFEXTinf, SFEXT'sup and SFEXT'inf) and by manufacturing the NYI core so that the external peripheral surface (SPE) of said NYI core corresponds to or is formed from said internal surface SFINTVAC of said volume of air defined in the computer data set.

[0195] In particular, it may be provided that the step of manufacturing the outer shell CQE comprises the manufacturing of an outer shell mold CQE, configured to have a molding surface defined by said external geometric surface SFEXTVAC1 in order to obtain by molding, preferably by injection, using said outer shell mold, the outer shell of the waveguide device whose internal peripheral surface SPI corresponds to said external geometric surface SFEXTVAC1 defined in said computer data set. And it may be provided that the step of manufacturing the core NYI comprises the manufacturing of a core mold NYI configured to have a molding surface defined by said external geometric surface SFEXTVAC1 of the data set, in order to obtain by molding using said core mold, the core of the guide device whose external peripheral surface SPE corresponds to said external geometric surface of said computer data set.

[0196] Waveguiding device

[0197] According to one embodiment, the waveguide comprises an outer shell and an inner core surrounded by the outer shell and which delimit between them a waveguide channel whose inner surfaces, formed by the inner peripheral surface of the outer shell and the outer peripheral surface of the core, have characteristics corresponding to the characteristics of the surfaces SFEXTVAC 1 and SFINTVAC detailed previously. It is understood that the outer contour and the inner contour of the annular inlet opening 110 correspond respectively to the outer contour and the inner contour of the corresponding inlet surface SI. The outer contour of the rectangular outlet opening 190 corresponds to the outer contour of the corresponding outlet surface S9.

[0198] The inner and outer paths each have the same length equal to the reference length dl9max.

[0199] It is understood that, for example for molding constraints, the solid surface SPI of the external shell and / or the solid surface SPE of the core may have modifications compared to the generated geometric surfaces SFEXTVAC1 and SFINTVAC. Thus and as discussed previously, angular areas (introducing slope discontinuities) may be modified to have a circular arc.

[0200] As for example illustrated in [Fig.3C] in connection with the other figures, such as Figures 5 to 10, for an upper lateral portion PSlsup of the annular inlet surface SI, and a lateral portion PS9sup of the outlet surface S9, defined by section of the set of inlet and outlet surfaces SI, S9 along said vertical plane of symmetry PN1 and said horizontal median plane PN2, said upper lateral portion being located on one side of the plane PN2 called the upper side and on one side of the plane PN1, called the first lateral side; the first external path (which belongs to the surface PSI of the external shell), for a first pair of points P1ES1; P1ES9 which comprises a first point P1ES1 of the external contour PCES1 of the upper lateral portion PSlsup of the entry surface SI located in the horizontal median plane PN2, and a first point P1ES9 of the external contour PCES9 of the upper lateral portion PS9sup of the exit surface S9 located in said horizontal median plane PN2, has a length equal to the reference length dl9max.

[0201] For a second pair of points P2ES1; P2ES9 comprising a second point P2ES1 of the outer contour PCES1 of the upper lateral portion PSlsup of the input surface SI, which belongs to the vertical plane of symmetry PN1, and a second point P2ES9 of the outer contour PCES9 of the upper lateral portion PS9sup of the output surface S9, which belongs to the vertical plane of symmetry PN1; the second external path, in the vertical plane of symmetry PN1, which connects said second point P2ES1 of the external contour PCES1 of the upper lateral portion PSlsup of the entry surface SI and said second point P2ES9 of the external contour PCES9 of the upper lateral portion (PS9sup) of the exit surface S9, comprises - a first segment SDE2, called opening segment, the majority of which PSDE2 ( [Fig.3C]) belongs to the inner peripheral surface SPI of the outer shell CQE, and which is inclined at an angle corresponding to the upper opening angle, relative to the intersection axis A12 of the two planes PN1, PN2 between them, and - a second segment SRE2, called the folding segment, the majority of which PSRE2 ([Fig.3C]) belongs to the inner peripheral surface SPI of the outer shell CQE, and which extends the first segment SDE2 up to said second point P2ES1 of the outer contour PCES1 of the upper lateral portion PSlsup of the entry surface S1, the length of said external path being equal to said determined reference length dl9max, the junction point of the two segments SDE2, SRE2 is called external vertex STE2.

[0202] For a plane of upper exterior vertices PSSE passing through said exterior vertex STE2 and said first point P1ES9 of the exterior contour PCES9 of the upper lateral portion PS9sup of the exit surface S9, and the center 09 of the rectangular exit surface S9; and, for several other pairs of intermediate points PiESl; PiES9, located between the first and second pairs of points P1ES1; P1ES9, P2ES1; P2ES9, each pair of intermediate points comprising a point PiES1 of the outer contour PCES1 of the first upper lateral portion PSlsup of the input surface SI and a corresponding point PiES9 of the outer contour PCES9 of the first upper lateral portion PS9sup of the output surface S9: considering the intermediate external path formed by an opening segment SDEi the majority of which belongs to the inner peripheral surface SPI of the outer shell CQE and a folding segment SREi the majority of which belongs to the inner peripheral surface SPI of the outer shell CQE, and which connect said intermediate points PiESl, PiES9 of said pair of points, the junction point STEi of said segments SDEi, SREi belonging to the plane of outer upper vertices PSSE, the length of said intermediate external path is equal to said reference length dl9max.

[0203] Considering a first interior path, for a first pair of points P1IS1; P1IS9 which comprises a first point P1IS1 of the interior contour PCIS1 of the upper lateral portion PSlsup of the entry surface SI located in the horizontal median plane PN2, and a first point P1IS9 of the interior contour PCIS9 of the upper lateral portion PS9sup of the exit surface S9 located in said horizontal median plane PN2, the length of said first interior path is equal to the reference length. As a reminder, the interior contour PCIS9 of the upper portion PS9sup of the exit surface S9 corresponds to the segment of the exit surface S9 which extends in the vertical plane of symmetry PN1 and which results from the section of the exit surface S9 according to said vertical plane of symmetry PN1 and said horizontal median plane PN2.

[0204] For a second pair of points P2IS1; P2IS9 comprising a second point P2ES1 of the inner contour PCIS1 of the upper lateral portion PSlsup of the input surface SI, which belongs to the vertical plane of symmetry PN1, and a second point P2IS9 of the inner contour PCIS9 of the upper lateral portion PS9sup of the output surface S9, which belongs to the vertical plane of symmetry PN1; considering the second interior path, in the vertical PN 1 symmetry plane, which connects said second point P2IS1 of the inner contour PCIS1 of the upper lateral portion PSlsup of the input surface SI and said second point P2IS9 of the inner contour PCIS9 of the upper lateral portion PS9sup of the output surface S9, the second inner path comprising: - a first segment SDI2, called the opening segment, the majority of which PSDI2 belongs to the outer peripheral surface SPE of the NYI core and which is inclined by the said upper opening angle aouv_sup, relative to the axis of intersection A12 of the two planes PN1, PN2 between them, and - a second segment SRI2, called a folding segment, the majority of which PSRI2 belongs to the outer peripheral surface SPE of the core NYI and which extends the first segment SDI2 to said second point P2IS1 of the inner contour PCIS1 of the upper lateral portion PSlsup of the input surface SI, the junction point between straight lines passing through the two segments SDI2, SRI2 being called the inner vertex STI2; the length of said second outer path is equal to said reference length dl9max.

[0205] For a plane, called the upper interior vertex plane, passing through said interior vertex STI2 and said first point P1IS9 of the interior contour PCIS9 of the upper lateral portion PS9sup of the exit surface S9, and the center 09 of the rectangular exit surface S9; and, for several other pairs of intermediate points PilS 1 ; PiIS9, located between the first and second pairs of points P1IS1 ; P1IS9, P2IS1 ; P2IS9, each pair of intermediate points comprising a point PilS1 of the interior contour PCIS1 of the first upper lateral portion PSlsup of the entry surface SI and a corresponding point PiIS9 of the interior contour PCIS9 of the first upper lateral portion PS9sup of the exit surface S9: considering each interior path, called intermediate interior path, which connects points PilS 1, PiIS9 of a pair of intermediate points, and which comprises an opening segment SDIi the majority of which belongs to the outer peripheral surface SPE of the core NYI and a folding segment SRIi the majority of which belongs to the outer peripheral surface SPE of the core NYI and which are defined so that the junction point STIi of said segments SDIi, SRIi belongs to the plane of interior upper vertices, each intermediate interior path has a length equal to the reference length dl9max.

[0206] The description given below for the upper lateral portions PSlsup, PS9sup (which form the inlet and outlet surface portions of the volume delimited by the surface SPEsup and the surface SPIsup), also applies to the lower lateral portions PSlinf, PS9inf (which form the inlet and outlet surface portions of the volume delimited by the surface SPEinf and the surface SPIinf) by replacing the upper opening angle with the lower opening angle. The waveguide having a plane of symmetry PN1, the description also applies, by symmetry of plane PN1, to the other upper lateral portions PSl'sup, PS9'sup (which form the inlet and outlet surface portions of the volume delimited by the surface SPE'sup and the surface SPI'sup), and to the other lower lateral portions PSl'inf, PS9'inf (which form the inlet and outlet surface portions of the volume delimited by the surface SPE'inf and the surface SPI'inf).

[0207] The invention is not limited to the embodiments illustrated in the drawings. Accordingly, it should be understood that, where the features mentioned in the appended claims are followed by reference signs, these signs are included solely for the purpose of improving the intelligibility of the claims and are in no way limiting the scope of the claims.

[0208] Furthermore, the term "comprising" does not exclude other elements or steps. Furthermore, features or steps that have been described with reference to one of the embodiments set forth above may also be used in combination with other features or steps of other embodiments set forth above.

Claims

Claims

1. A method of manufacturing a waveguide device (100), the waveguide device (100) comprising: - an external peripheral wall (EPW), called the external shell, - an internal peripheral wall (INW), called core, surrounded by the external shell (ESC); the outer shell (CQE) and the core (NYI) delimiting between them: - an inlet opening (110) which has an annular inlet surface (SI), and to which an acoustic wave generator system (SG) is capable of being connected, - an outlet opening (190), called a mouth, having a rectangular outlet surface (S9), the outer diameter of the annular inlet opening (110) being less than the length of the long side of the rectangle of the outlet opening (190), and being greater than half the length of the long side of the rectangle of the outlet opening (190), the two inlet and outlet surfaces (SI, S9) together having a plane of symmetry (PN1), called a vertical plane of symmetry, passing between the two long sides of the rectangle of the outlet surface (S9), and a median plane (PN2), called a horizontal median plane, orthogonal to the vertical plane of symmetry (PN1), said planes (PN1, PN2) passing through the center (01) of the annular inlet surface (SI) and through the center (09) of the rectangular outlet surface (S9), - an acoustic wave guiding channel (CNL1) communicating between the inlet opening (110) and the outlet opening (190) and defined between an internal peripheral surface (SPI) of the external shell (CQ) and an external peripheral face (SPE) of the core (NYI); characterized in that the method comprises: - the generation using a computer system of an external surface (SFEXTVAC) and an internal surface (SFINTVAC) of the volume delimited by the wave guide channel (CNL1) between the annular input surface (SI) and the rectangular output surface (S9); - manufacturing the outer shell (CQE) such that the inner peripheral surface (IPS) of said outer shell (CQE) is defined as a function of said outer surface (SFEXTVAC) of said volume, and the outer peripheral surface (IPS) of said core (NYI) is defined as a function of said inner surface (SFINTVAC) of said volume of the channel wave guidance; and in that said generation of the external surface (SFEXTVAC) and the internal surface (SFINTVAC) of the volume of the waveguiding channel comprises the following steps: a) cutting the set of inlet and outlet surfaces (SI, S9) along said vertical plane of symmetry (PN1) and said horizontal median plane (PN2) to obtain a portion (PSlsup), called the upper lateral portion, of the annular inlet surface (SI), and a portion, called the upper lateral portion (PS9sup), of the outlet surface (S9); b) determining a path, called the first exterior path, for a first pair of points (PIESI; P1ES9) comprising a first point (P1ES1) of the exterior contour (PCES1) of the upper lateral portion (PSlsup) of the inlet surface (SI) located in the horizontal median plane (PN2), and a first point (P1ES9) of the exterior contour (PCES9) of the upper lateral portion (PS9sup) of the outlet surface (S9) located in said horizontal median plane (PN2); the length of the path (dl9max) being called the reference length; c) for a second pair of points (P2ES1; P2ES9) comprising a second point (P2ES1) of the outer contour (PCES1) of the upper lateral portion (PSlsup) of the input surface (SI), which belongs to the vertical plane of symmetry (PN1), and a second point (P2ES9) of the outer contour (PCES9) of the upper lateral portion (PS9sup) of the output surface (S9), which belongs to the vertical plane of symmetry (PN1); determining a second external path, in the vertical plane of symmetry (PN1), which connects said second point (P2ES1) of the external contour (PCES1) of the upper lateral portion (PSlsup) of the entry surface (SI) and said second point (P2ES9) of the external contour (PCES9) of the upper lateral portion (PS9sup) of the exit surface (S9), said second external path comprising: - a first segment (SDE2), called the opening segment, inclined by an angle of predefined value, called the upper opening angle (aouv_sup), relative to the axis of intersection (A 12) of the two planes (PN1, PN2) with each other, and - a second segment (SRE2), called a folding segment, which extends the first segment (SDE2) to said second point (P2ES1) of the outer contour (PCES1) of the upper lateral portion (PSlsup) of the entry surface (SI), the length of said second external path being equal to said determined reference length (dl9max), the junction point between the two segments (SDE2, SRE2) being called the exterior vertex (STE2); d) definition of a plane, called the upper exterior vertex plane, (PSSE) passing through said exterior vertex (STE2) and said first point (P1ES9) of the exterior contour (PCES9) of the upper lateral portion (PS9sup) of the output surface (S9), and the center (09) of the rectangular output surface (S9); e) for several other pairs of intermediate points (PiESl; PiES9), located between the first and second pairs of points (P1ES1; P1ES9, P2ES1; P2ES9), each pair of intermediate points comprising a point (PiESl) of the outer contour (PCES1) of the first upper lateral portion (PSlsup) of the entry surface (SI) and a corresponding point (PiES9) of the outer contour (PCES9) of the first upper lateral portion (PS9sup) of the exit surface (S9): determination of an exterior path, called intermediate exterior path, formed by an opening segment (SDEi) and a folding segment (SREi) which connect said intermediate points (PiESl, PiES9) of said pair of points, the junction point (STEi) between said segments (SDEi, SREi) belonging to the plane of exterior upper vertices (PSSE), the length of said exterior path being equal to said determined reference length (dl9max); f) repeating the preceding steps b) to e) with the inner contour (PCIS1) of the upper portion (PSlsup) of the input surface (SI) and the inner contour (PCIS9) of the first lateral upper portion (PS9sup) of the output surface (S9), to generate paths, called inner paths, having inner vertices (STI1, STIi, STI9), said inner paths being formed between pairs of points (P1IS1; P1IS9; P2IS1; P2IS9; PilSl; PiIS9) which each comprise a point (P1IS1; PilSl; P2IS1) belonging to the inner contour (PCIS1) of the upper portion (PSlsup) of the input surface and a corresponding point (P1IS9; PiIS9; P2IS9) belonging to the inner contour (PCIS9) of the lateral upper portion (PS9sup) of the output surface (S9), the inner contour (PCIS9) of the upper portion (PS9sup) of the output surface (S9) corresponding to the segment in the vertical symmetry plane (PN1) which results from the cutting of the surface of output (S9) according to said vertical plane of symmetry (PN1) and said horizontal median plane (PN2); g) generation of an outer upper surface (SFEXTsup) which passes through the outer paths (SREi, SDEi) determined between said pairs of points of said outer contours; h) generation of an interior upper surface (SFINTsup) which passes through the interior paths (SRIi, SDIi) determined between said pairs of points of said interior contours; And : either, when the horizontal median plane (PN2) is not a plane of symmetry, then, for the lower lateral portions (PSlinf, PS9inf) of the inlet (SI) and outlet (S9) surfaces which are located, with respect to the horizontal median plane (PN2), on the opposite side to said upper lateral portions (PSlsup, PS9sup) of the inlet (SI) and outlet (S9) surfaces, and on the same side of the vertical plane of symmetry (PN1) as the upper lateral portions (PSlsup, PS9sup) of the inlet (SI) and outlet (S9) surfaces, and for a predefined lower opening angle (aouv_inf): i) repeating the previous steps b) to h) applied to the lower portions (PSlinf, PS9inf) to determine exterior paths and interior paths associated with said lateral lower portions (PSlinf, PS9inf), and generating a lower exterior surface (SFEXTinf) and a lower interior surface (SFINTinf) based on the determined exterior paths and interior paths; either, when the horizontal median plane (PN2) is a plane of symmetry, ii) generation of a lower exterior surface (SFEXTinf) and a lower interior surface (SFINTinf) by symmetry, with respect to the horizontal median plane (PN2), of the upper exterior surface (SFEXTsup) and of the upper interior surface (SFINTsup); j) generating an additional lower outer surface (SFEXT'inf), an additional upper outer surface (SFEXT'sup), an additional lower inner surface (SFINT'inf) and an additional lower inner surface (SFINT'sup) by symmetry, with respect to the vertical plane of symmetry (PN1), of said lower outer surface (SFEXTinf), of said upper outer surface (SFEXTsup), of said lower inner surface (SFINTinf) and of said lower inner surface (SFINTsup);

2.

3. said external surface (SFEXTVAC) of the volume (VACNL1) of the wave guide channel being formed by the joined assembly of said external surfaces (SFEXTsup, SFEXTinf, SFEXT'sup, SFEXT'inf); said external surface (SFINTVAC) of the volume (VACNL1) of the wave guide channel being formed by the joined assembly of said internal surfaces (SFINTsup, SFINTinf, SFINT'sup and SFINT'inf). Method according to claim 1, in which, for each pair of intermediate points (PiESl; PiES9), the ratio of the length between the intermediate point (PiESl) of the outer contour of the inlet surface (SI) and the first point (PiESl) of the outer contour of the upper lateral portion (PSlsup) of the inlet surface (SI), to the length of the outer contour (PCESlsup) of the upper lateral portion (PSlsup) of the inlet surface (SI), is equal to the ratio of the length between the corresponding intermediate point (PiES9) of the outer contour of the outlet surface (S9) and the first point (P1ES9) of the outer contour of the upper lateral portion (PSlsup) of the outlet surface (S9) to the length of the outer contour (PCES9sup) of the upper lateral portion (PSlsup) of the inlet surface (S9). Method according to claim 1 or 2, wherein said pairs of points (P1IS1; P1IS9; P2IS1; P2IS9; PilSl; PiIS9) of inner contour comprise: a first pair of points (P1IS1; P1IS9) comprising a first point (PIIS 1 ) of the inner contour (PCIS1) of the upper lateral portion (PSlsup) of the entry surface (SI) located in the horizontal median plane (PN2), and a first point (P1IS9) of the inner contour (PCIS9) of the upper lateral portion (PS9sup) of the exit surface (S9) located in said horizontal median plane (PN2), the length of the path between said points being equal to the reference length (dl9max); a second pair of points (P2IS1; P2IS9) comprising a second point (P2IS1) of the inner contour (PCIS1) of the upper lateral portion (PSlsup) of the input surface (SI), which belongs to the vertical plane of symmetry (PN1), and a second point (P2IS9) of the inner contour (PCIS9) of the upper lateral portion (PS9sup) of the output surface (S9), which belongs to the vertical plane of symmetry (PN1); pairs of intermediate points (PilS 1, PiIS9) located between the first and second pairs of points (P1IS1; P1IS9, P2IS1; P2IS9), each pair of intermediate points comprising a point (PilS 1) of the contour interior (PCIS1) of the first upper lateral portion (PSlsup) of the inlet surface (SI), and a corresponding point (PiIS9) of the interior contour (PCIS9) of the first upper lateral portion (PS9sup) of the outlet surface (S9); the second point (P2IS9) of the interior contour (PCIS9) of the upper lateral portion (PS9sup) of the outlet surface (S9) being spaced from the second point (P2ES9) of the exterior contour (PCES9) of the upper lateral portion (PS9sup) of the outlet surface (S9) by a distance equal to the distance between the second point (P2IS1) of the interior contour (PCIS1) of the upper lateral portion (PSlsup) of the inlet surface (SI) and the second point (P2ES1) of the exterior contour (PCES1) of the upper lateral portion (PSlsup) of the inlet surface (SI).

4. Method according to any one of the preceding claims, wherein the inner peripheral surface (SPI) of said outer shell (CQE) corresponds to said outer surface (SFEXTVAC) of said volume of the wave guiding channel, for which the slope discontinuity zone formed by the inner vertices (STIi, STIiinf) is replaced by a curved zone to obtain slope continuity of the inner peripheral surface, and the outer peripheral surface (SPE) of said core (NYI) corresponds to said inner surface (SFINTVAC) of said volume of the wave guiding channel for which the slope discontinuity zone formed by the outer vertices (STEi, STEiinf) is replaced by a curved zone to obtain slope continuity of the inner peripheral surface.

5. Method according to any one of the preceding claims, in which the upper opening angle (aouv_sup), respectively the lower opening angle (aouv_sup), is defined as a function of, is preferably equal to, the angle formed by an upper face (11), respectively a lower face (12), of the housing (10) of the enclosure (1) in which the waveguide device is intended to be housed, with the median plane of the housing (10) of said enclosure (1) which is orthogonal to the output face of the housing (10) opposite which the output opening (190) of the waveguide device is intended to be oriented.

6. A method according to any preceding claim, wherein the rectangular outlet surface (S9) is equal to or larger than the annular inlet surface (SI).

7. A method according to any preceding claim, wherein the waveguide device (100) is housed in a housing (10). enclosure (1), the outlet opening (190) has a height equal to at least 80% of the height of the outlet face of the housing (10) of the enclosure (1).

8. Method according to any one of the preceding claims, in which the outer shell (CQE) and the core (NYI) are each produced by molding, preferably by plastic injection.

9. A method according to any preceding claim, wherein the upper opening angle and / or the lower opening angle has a value in the range [5°; 30°].

10. Waveguide device (100), obtained by the method according to any one of the preceding claims.

11. Waveguide device (100) comprising: - an outer peripheral wall (CQE), called outer shell, - an inner peripheral wall (NYI), called core, surrounded by the outer shell (CQE); the outer shell (CQE) and the core (NYI) delimiting between them: - an inlet opening (110) which has an annular inlet surface (SI), and to which an acoustic wave generator (SG) is capable of being connected, - an outlet opening (190), called a mouth, having a rectangular outlet surface (S9), the outer diameter of the annular inlet opening (110) being less than the length of the long side of the rectangle of the outlet opening (190), and being greater than half the length of the long side of the rectangle of the outlet opening (190), the set of the two inlet and outlet surfaces (SI, S9) having a plane of symmetry (PN1), called the vertical plane of symmetry,passing between the two large sides of the rectangle of the exit surface (S9), and a median plane (PN2), called the horizontal median plane, orthogonal to the vertical plane of symmetry (PN1), said planes (PN1, PN2) passing through the center (01) of the annular entry surface (SI) and through the center (09) of the rectangular exit surface (S9), - an acoustic wave guiding channel (CNL1) communicating between the entry opening (110) and the exit opening (190) and defined between an internal peripheral surface (SPI) of the external shell (CQE) and an external peripheral surface (SPE) of the core (NYI); characterized in that, for a portion (PSlsup), called the upper lateral portion, of the annular entry surface (SI), and a portion, called the upper lateral portion (PS9sup) of the exit surface (S9), defined by cutting the set of entry and exit surfaces (SI, S9) according to said vertical plane of symmetry (PN1) and said horizontal median plane (PN2), said upper lateral portion being located on one side of the plane (PN2) called the upper side and on one side of the plane (PN1), called the first lateral side; the path, called the first external path, for a first pair of points (PIESI; P1ES9) which comprises a first point (PIESI) of the external contour (PCES1) of the upper lateral portion (PSlsup) of the entry surface (SI) located in the horizontal median plane (PN2), and a first point (P1ES9) of the external contour (PCES9) of the upper lateral portion (PS9sup) of the exit surface (S9) located in said horizontal median plane (PN2), has a length (dl9max) called the reference length; for a second pair of points (P2ES1; P2ES9) comprising a second point (P2ES1) of the outer contour (PCES1) of the upper lateral portion (PSlsup) of the input surface (SI), which belongs to the vertical plane of symmetry (PN1), and a second point (P2ES9) of the outer contour (PCES9) of the upper lateral portion (PS9sup) of the output surface (S9), which belongs to the vertical plane of symmetry (PN1); the second external path, in the vertical plane of symmetry (PN1), which connects said second point (P2ES1) of the external contour (PCES1) of the upper lateral portion (PSlsup) of the entry surface (SI) and said second point (P2ES9) of the external contour (PCES9) of the upper lateral portion (PS9sup) of the exit surface (S9), comprises: - a first segment (SDE2), called the opening segment, the majority of which (PSDE2) belongs to the inner peripheral surface (SPI) of the outer shell (CQE), and which is inclined by an angle of predefined value, called the upper opening angle (aouv_sup), relative to the axis of intersection (A12) of the two planes (PN1, PN2) between them, and - a second segment (SRE2), called the folding segment, the majority of which (PSRE2) belongs to the inner peripheral surface (SPI) of the outer shell (CQE), and which extends the first segment (SDE2) to said second point (P2ES1) of the outer contour (PCES1) of the upper lateral portion (PSlsup) of the entry surface (SI), the length of said outer path being equal to said length of reference (dl9max) determined, the junction point of the two segments (SDE2, SRE2) being called the exterior vertex (STE2); for a plane, called the upper exterior vertex plane, (PSSE) passing through said exterior vertex (STE2) and said first point (P1ES9) of the exterior contour (PCES9) of the upper lateral portion (PS9sup) of the exit surface (S9), and the center (09) of the rectangular exit surface (S9); and, for several other pairs of intermediate points (PiES 1; PiES9), located between the first and second pairs of points (PIESI; P1ES9, P2ES1; P2ES9), each pair of intermediate points comprising a point (PiESl) of the outer contour (PCES1) of the first upper lateral portion (PSlsup) of the entry surface (SI) and a corresponding point (PiES9) of the outer contour (PCES9) of the first upper lateral portion (PS9sup) of the exit surface (S9): considering the outer path, called the intermediate outer path, formed by an opening segment (SDEi) the majority of which belongs to the inner peripheral surface (SPI) of the outer shell (CQE) and a folding segment (SREi) the majority of which belongs to the inner peripheral surface (SPI) of the outer shell (CQE), and which connect said intermediate points (PiESl, PiES9) of said pair of points, the junction point (STEi) of said segments (SDEi, SREi) belonging to the outer upper vertex plane (PSSE), the length of said intermediate outer path is equal to said reference length (dl9max); considering the path, called the first interior path, for a first pair of points (P1IS1; P1IS9) which comprises a first point (PUS 1 ) of the interior contour (PCIS1) of the upper lateral portion (PSlsup) of the entry surface (SI) located in the horizontal median plane (PN2), and a first point (P1IS9) of the interior contour (PCIS9) of the upper lateral portion (PS9sup) of the exit surface (S9) located in said horizontal median plane (PN2), the length of said first interior path is equal to the reference length; the interior contour (PCIS9) of the upper portion (PS9sup) of the exit surface (S9) corresponding to the segment of the exit surface (S9) which extends in the vertical plane of symmetry (PN1) and which results from the cutting of the exit surface (S9) according to said vertical plane of symmetry (PN1) and said plane horizontal median (PN2); for a second pair of points (P2IS1; P2IS9) comprising a second point (P2ES1) of the inner contour (PCIS1) of the upper lateral portion (PSlsup) of the input surface (SI), which belongs to the vertical plane of symmetry (PN1), and a second point (P2IS9) of the inner contour (PCIS9) of the upper lateral portion (PS9sup) of the output surface (S9), which belongs to the vertical plane of symmetry (PN1); considering the second interior path, in the vertical plane of symmetry (PN1), which connects said second point (P2IS1) of the interior contour (PCIS1) of the upper lateral portion (PSlsup) of the entry surface (SI) and said second point (P2IS9) of the interior contour (PCIS9) of the upper lateral portion (PS9sup) of the exit surface (S9), the second interior path comprising: - a first segment (SDI2), called the opening segment, the majority of which (PSDI2) belongs to the outer peripheral surface (SPE) of the core (NYI) and which is inclined at said upper opening angle (aouv_sup), relative to the axis of intersection (A 12) of the two planes (PN1, PN2) between them, and - a second segment (SRI2), called the folding segment, the majority of which (PSRI2) belongs to the outer peripheral surface (SPE) of the core (NYI) and which extends the first segment (SDI2) to said second point (P2IS1) of the inner contour (PCIS1) of the upper lateral portion (PSlsup) of the input surface (SI), the junction point between straight lines passing through the two segments (SDI2, SRI2) being called the inner vertex (STI2); the length of said second outer path is equal to said reference length (dl9max), for a plane, called the upper inner vertex plane, passing through said inner vertex (STI2) and said first point (P1IS9) of the inner contour (PCIS9) of the upper lateral portion (PS9sup) of the output surface (S9), and the center (09) of the rectangular output surface (S9) and, for several other pairs of intermediate points (PilSl; PiIS9), located between the first and second pairs of points (P1IS1; P1IS9, P2IS1; P2IS9), each pair of intermediate points comprising a point (PilSl) of the inner contour (PCIS1) of the first upper lateral portion (PSlsup) of the entry surface (SI) and a corresponding point (PiIS9) of the inner contour (PCIS9) of the first su- lateral periphery (PS9sup) of the output surface (S9): considering each interior path, called intermediate interior path, which connects points (PilS 1, PiIS9) of a pair of intermediate points, and which comprises an opening segment (SDIi) the majority of which belongs to the outer peripheral surface (SPE) of the core (NYI) and a folding segment (SRIi) the majority of which belongs to the outer peripheral surface (SPE) of the core (NYI) and which are defined so that the junction point (STIi) of said segments (SDIi, SRIi) belongs to the plane of interior upper vertices, each intermediate interior path has a length equal to the reference length dl9max.

12. Device according to claim 11, wherein the inner peripheral surface (SPI), and / or respectively the outer peripheral surface (SPE), comprises a circular arc portion (ACE; ACI) which connects together the folding segment portions (PSRE2; PSRI2) and the opening segment portions (PSDE2; PSDI2) which belong to the inner peripheral surface (SPI), respectively to the outer peripheral surface (SPE), so that said segment portions (PSRE2; PSRI2; PSDE2; PSDI2) are tangent to the corresponding circular arc (ACE; ACI).

13. Device according to claim 12, wherein the lengths of outer paths and inner paths associated with lower lateral portions (PSlinf, PS9inf) of the inlet and outlet surfaces, located relative to said upper lateral portions (PSlsup, PS9sup) on the other side of the horizontal median plane (PN2), are equal to said reference length (dl9max).

14. Device according to any one of claims 10 to 13, in which the acoustic wave generator system (SG) is capable of being connected to the inlet opening (110) of the outer shell, either directly or indirectly by a connection device (CAI) whose inlet opening has a disc-shaped surface (SDCAE1).

15. Device according to claim 14, wherein the internal volume of the connecting device (CAI) is defined between an internal cone (CAI1) connected to the core (NYI) and an external cone truncated (CAE1) connected to the external shell (CQE).

16. Device according to claim 14 or 15, in which the connecting device (CAI) has two internal surfaces which define between them a passage whose entrance is a disc-shaped surface and the outlet is an annular-shaped surface connected to the outer shell inlet (ECH), the two inner surfaces being configured so as not to introduce a difference in sound wave propagation time between the two inner surfaces.

17. An enclosure comprising a housing (10) and, housed in the housing, a waveguide device (100) according to any one of claims 10 to 16, and an acoustic wave generator system (SG) connected to the waveguide device.

18. Set of superimposed speakers (1, 1'), each speaker (1, 1') being in accordance with claim 17, the speakers (1, 1') being configured so that acoustic waves emerging from said speakers (1, 1') are in phase.

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