EP1635606B1 - Public address systems with adjustable directivity - Google Patents

Abstract

The system has a loudspeaker enclosure (E1) including an expansion guide (3) having a movable flap that is displaced by a predetermined movement parallel to a plane (P). Another loudspeaker enclosure forms a line source array with the enclosure (E1) and includes a movable flap displaced independent of the former flap, where the line source array extends along a direction transversal to the plane.

Description

The invention relates generally to sound reinforcement techniques.

More specifically, the invention relates to a sound system at least consisting of a first acoustic chamber equipped with at least one acute sound reproduction section, the acute sound section comprising at least one transducer and a guide for expanding sound. wave, the expansion guide having an inlet and an outlet respectively relatively close and relatively remote from the transducer, this expansion guide receiving at its input the sound waves emanating from the transducer and having, at least in projection in a first plane, a shape flaring from its entrance to its outlet to spread in a solid emission angle the sound waves emerging from this expansion guide.

Systems of this type are well known to those skilled in the art.

One of the major problems with the sound system lies in the difficulty of rendering clearly, particularly in a closed space such as a theater, the sounds typically in the range of 300 Hz to 20 kHz, and especially the most acute sounds in the range of 1300 Hz to 20 kHz.

Indeed, to the extent that, unlike the bass sounds that is to say the sounds whose frequency is typically less than 300 Hz, the acute sounds or average frequency have a relatively low wavelength, these sounds are most likely to reflect and recombine by forming multiple interferences and sound delays that alter the quality of the sound reproduced.

Examples of public address systems are taught by the documents US 6,394,223 and US 2004/0131217 .

The invention, which is in this context, aims to provide a sound system for a sound quality significantly higher than existing systems.

To this end, the system of the invention, moreover in conformity with the generic definition given in the preamble above, is essentially characterized in that the expansion guide of the first enclosure comprises at least a first movable component movable by a movement carried out parallel to the first plane, said solid emitting angle thus having a value that can be adjusted by moving the first flap.

By "movement carried out parallel to the foreground" is meant for example a movement in a circular arc parallel to the first plane and thus producing a rotation of the first component about an axis at least substantially perpendicular to this first plane, or a movement in line segment parallel to the foreground and thus producing a translation of the first component relative to its initial position.

Thanks to this arrangement, which confers on the first speaker an adjustable directivity, it is possible to concentrate in an adjustable solid angle the energy of the sound waves emerging from the expansion guide and to avoid that these waves do not come unnecessarily to strike. partitions of the sound space causing interference and sound delays, with the additional benefit of increasing the energy density of the waves to make the longest course.

The sound system of the invention may then comprise at least a second acoustic enclosure similar to the first and forming, at least with the first enclosure, a one-dimensional network of sound sources extending in a direction substantially transverse to the first plane, the second enclosure comprising at least a first mobile flap movable independently of the first movable flap of the first enclosure.

By "second acoustic enclosure similar to the first" is meant, in the present description, a second acoustic enclosure possibly strictly identical to the first enclosure but which, without necessarily being, has at least the characteristics which, over time, description, are explicitly attributed to the first speaker as it is described.

By "direction substantially transverse to the foreground" is meant, in the present description, a direction which, without necessarily being strictly perpendicular to the first plane, makes a significant angle with the latter, for example at least 70 degrees.

The sound system thus defined forms a one-dimensional network of sound sources, that is to say a system universally known to those skilled in the art under its Anglo-Saxon name "Line Source Array".

The section of the acute sounds of each chamber advantageously comprises a waveguide connecting the transducer to the inlet of the expansion guide, this waveguide may have, opposite the inlet of the expansion guide, an output slit-shaped oriented in a direction substantially transverse to the foreground.

To do this, the waveguide can be realized according to the teaching of the EP Patent 0 331 566 or its American counterpart, US 5,163,167 .

In addition to the first component, the expansion guide of each enclosure may also include a second movable component, also movable by a movement made parallel to the foreground, to change the value of the solid emission angle.

Furthermore, it is advisable to provide that the expansion guide of each enclosure is at least partially delimited by walls extending substantially transversely to the foreground and comprising two inlet walls extending from the entrance of this guide two exit walls extending to the outlet of this expansion guide, that the inlet walls form between them a relatively closed first angle, that the exit walls are respectively connected to the walls of the entering into respective connection areas and form between them a second relatively open angle, and that each movable flap is disposed in the solid emission angle at least partially inside the second angle, facing a wall of corresponding output, to selectively adopt a relatively close position or a position relatively remote from the corresponding output wall.

Each enclosure is for example symmetrical with respect to a median plane perpendicular to the first plane, the two inlet walls of the expansion guide of this enclosure being symmetrical to each other with respect to this median plane, and the two output walls of the same expansion guide being equally symmetrical to each other with respect to this median plane.

In a preferred embodiment of the invention, each flap forms a non-zero angle with the corresponding outlet wall and is movably mounted by translation parallel to the first plane, between a relatively low directivity position, in which this flap is relatively distant from the connection area of the corresponding outlet wall and in which the sound waves emerging from the expansion guide are guided by the wall of corresponding output, and a relatively high directivity position, in which this flap is relatively close to or in support of the zone of connection of the corresponding outlet wall, and in which the sound waves emerging from the expansion guide are guided by this component.

Each flap may in this case have, in the connection zone, a leading edge adopting substantially the same orientation as the inlet wall to which the corresponding outlet wall is connected and resting on this input wall in the relatively high directivity position of this flap.

In practice, it is possible to provide that the first angle is between 35 degrees and 55 degrees, preferably between 42 degrees and 48 degrees, the second angle is between 100 degrees and 140 degrees, preferably between 115 degrees and 125 degrees, and that each shutter forms with the median plane an angle of between 20 degrees and 40 degrees, preferably between 25 degrees and 35 degrees.

Insofar as the values of the aforementioned angles can only be strictly measured in the case where the shutters and the walls are flat, and to the extent that the flaps and the walls can very well, locally or globally, not be planes, it is useful to specify here that the values of the aforementioned angles are given by taking into account the general direction that each wall and each shutter adopts, such as this wall and this shutter are seen at the scale of the length of wave corresponding to an average frequency, for example of the order of 1300 Hz.

To achieve a sound system according to the invention, complete and relatively compact, it is possible to provide that each chamber comprises at least a first medium frequency sound reproducing section disposed against a first of the two input walls, to the outside of the solid emission angle and at least a first bass sound reproducing section disposed against a first of the two output walls, outside the solid emission angle.

• la figure 1 est une vue en coupe verticale d'un espace sonorisé au moyen d'un réseau unidimensionnel de sources sonores (Line Source Array) conforme ou non à l'invention;
• la figure 2 est une vue de dessus d'un espace sonorisé au moyen d'un réseau unidimensionnel de sources sonores (Line Source Array) conforme à l'invention;
• la figure 3 est une vue schématique, réalisée dans le premier plan P, d'un système de sonorisation constituée par une unique enceinte réalisée conformément à l'invention;
• les figures 4A et 4B sont des vues représentant à plus petite échelle l'enceinte illustrée à la figure 3 dans des configurations de directivité respectivement minimale et maximale;
• les figures 5A à 5D sont des vues en perspective d'un système de sonorisation constituée par une unique enceinte réalisée conformément à l'invention et respectivement illustrée dans une configuration de directivité maximale, dans une configuration de directivité minimale, dans une configuration de directivité dissymétrique, maximale à droite (sur la figure) et minimale à gauche, et dans une configuration de directivité dissymétrique, minimale à droite (sur la figure) et maximale à gauche;
• la figure 6 est une vue en perspective d'un exemple de dispositif de montage et de réglage de volets d'un système de sonorisation constituée par une unique enceinte réalisée conformément à l'invention; et
• les figures 7A à 7D sont des vues en coupe, réalisées suivant les plans les plus caractéristiques, d'un système de sonorisation constituée par une unique enceinte réalisée conformément à l'invention et respectivement illustrée dans une configuration de directivité maximale, dans une configuration de directivité minimale, dans une configuration de directivité dissymétrique, minimale à droite (sur la figure) et maximale à gauche, et dans une configuration de directivité dissymétrique, maximale à droite (sur la figure) et minimale à gauche.

Other characteristics and advantages of the invention will emerge clearly from the description which is given hereinafter, by way of indication and in no way limitative, with reference to the appended drawings, in which:

• the figure 1 is a vertical sectional view of a sound space using a one-dimensional network of sound sources (Line Source Array) compliant or not to the invention;
• the figure 2 is a top view of a sound space using a one-dimensional network of sound sources (Line Source Array) according to the invention;
• the figure 3 is a schematic view, made in the first plane P, of a sound system constituted by a single speaker made according to the invention;
• the Figures 4A and 4B are views representing on a smaller scale the speaker illustrated in the figure 3 in minimum and maximum directivity configurations respectively;
• the Figures 5A to 5D are perspective views of a sound system constituted by a single enclosure made according to the invention and respectively illustrated in a configuration of maximum directivity, in a configuration of minimum directivity, in a configuration of asymmetrical directivity, maximum on the right ( in the figure) and minimum on the left, and in an asymmetrical directivity configuration, minimum on the right (in the figure) and maximum on the left;
• the figure 6 is a perspective view of an exemplary device for mounting and adjusting shutters of a sound system constituted by a single enclosure made according to the invention; and
• the Figures 7A to 7D are sectional views, taken according to the most characteristic planes, of a sound system constituted by a single enclosure made according to the invention and respectively illustrated in a configuration of maximum directivity, in a configuration of minimum directivity, in a configuration of asymmetrical directivity, minimum on the right (in the figure) and maximum on the left, and in a configuration of asymmetrical directivity, maximum on the right (on the figure) and minimal on the left.

As previously announced, the invention relates to a sound system constituted by one or more loudspeakers such as E1 to E7.

The most striking interest of the invention is illustrated in Figures 1 and 2 , on which the system of the invention is represented in the form of a one-dimensional network of sound sources (Line Source Array), such as LSAg or LSAd, used for the sound of a space appearing in vertical section on the figure 1 .

Each of the speakers E1 to E7 of each of the networks LSAg and LSAd emits a beam of sound waves, such as SE1g to SE7g for the network LSAg ( figure 1 ), or such as SE1d and SE4d for the respective speakers E1 and E4 of the LSAd network ( figure 2 ).

In known manner, each network can, as shown in FIG. figure 1 , be constituted by a slightly curved column formed by stack of speakers E1 to E7, the different sound beams SE1g to SE7g having thus emitted selectively to the closest listeners for the speaker E1, and the farthest to the speaker E7 .

In the case of one-dimensional networks known from sound sources, the solid emission angle of the different beams such as SE1 to SE7 has the same divergence angle for all the beams, this angle of divergence being for example defined as the angle of divergence. the trace of each beam in the plane P substantially perpendicular to the stacking direction of the speakers E1 to E7.

Under these conditions, the need to give the beam SE1g an angle of divergence sufficient to sound the better the nearest audition area of the LSAg network leads to giving for example the SE7g beam an oversized divergence angle, leading to the appearance multiple sound delays of this beam by reflection on the partitions of the auditory space.

The invention, an effect of which is illustrated in figure 2 , solves this problem by providing speakers with adjustable directivity.

It is thus possible, as shown by figure 2 for example, to give the beams SE1g and SE1d a relatively large angle of divergence in order to sound better the nearest audition zone of the LSAg and LSAd networks, and to give other beams, for example to the beams SE4g and SE4d , a relatively small angle of divergence to sound best at an audition area farther away from the LSAg and LSAd networks by avoiding multiple reflections on the partitions of the auditory space, and correlatively concentrating the energy of the sound waves of these other beams, for example SE4g and SE4d, whose path is longer.

In a manner known per se ( figure 3 ), each speaker such as E1 is equipped with a section 11 for reproducing acute sounds, that is to say sounds whose frequency is typically at least 1300 Hz.

This section 11 generally comprises a transducer 20, such as a compression chamber motor, a waveguide 21, and a wave expansion guide 3, the waveguide 21 being interposed between the transducer 20 and the expansion guide 3.

This expansion guide 3 has an input 30 relatively close to the output 210 of the waveguide 21 and therefore of the transducer 20, and an output 31 relatively far from the output 210 of the waveguide 21 and thus of the transducer 20.

The expansion guide 3 receives at its input 30 the sound waves emanating from the transducer 20 and transmitted by the waveguide 21.

The guide 21 is for example made in accordance with the EP 0 331 566 or US 5,163,167 today universally known to those skilled in the art, and present, opposite the inlet 30 of the expansion guide 3, and as an outlet 210, a slot oriented in a direction substantially transverse to the plane P which is particularly constituted by the plan of Figures 3, 4A, 4B , and 7A to 7D .

The expansion guide 3 has meanwhile, in projection in the same plane P, a shape flaring from its inlet 30 to its outlet 31 to spread in a solid emission angle the sound waves emerging from this guide. expansion 3.

According to the invention, the expansion guide 3 of each enclosure such that E1 to E7 comprises at least one movable flap 32g and for example two movable flaps 32g and 32d.

Each movable flap such as 32g or 32d is displaceable by a movement carried out parallel to the plane P, so that the solid angle of emission of the acute and the medium frequency sound waves takes a value that can be adjusted by moving each flap 32g or 32d.

In the preferred and illustrated embodiment of the invention, the expansion guide 3 of each enclosure such that E1 to E7 is at least partially delimited by walls such as 33g, 33d, 34g, and 34d ( figure 3 in particular) which extend substantially transversely to the plane P.

These walls more precisely comprise two inlet walls, 33g and 33d, which extend from the inlet 30 of the expansion guide 3, and two outlet walls, 34g and 34d, which extend up to the outlet 31 of this expansion guide 3, the outlet walls 34g and 34d respectively connecting to the inlet walls 33g and 33d in respective connection areas 35g and 35d.

The inlet walls 33g and 33d form between them a relatively closed angle A1, for example between 35 degrees and 55 degrees, preferably between 42 degrees and 48 degrees, and which may be chosen to be equal to 45 degrees.

The outlet walls 34g and 34d form between them a relatively open angle A2, for example between 100 degrees and 140 degrees, preferably between 115 degrees and 125 degrees, and which can be chosen to be equal to 120 degrees.

As shown in particular figure 3 , each enclosure such that E1 to E7 may be symmetrical with respect to a median plane M perpendicular to the first plane P, of so that the two inlet walls 33g and 33d of the expansion guide 3 of this enclosure are symmetrical to each other with respect to this median plane M, and that the two outlet walls 34g and 34d of this same expansion guide 3 are also symmetrical to each other with respect to this median plane M.

Each movable flap such as 32g or 32d is disposed at least partially within the second angle A2, facing the left exit wall 34g for the left flap 32g, and facing the right exit wall 34d for the flap right 32d, each flap adopting at will a relatively close position or a position relatively remote from the corresponding outlet wall 34g or 34d.

For example, each movable flap such as 32g or 32d permanently forms a non-zero angle with the corresponding outlet wall 34g or 34d and is movably mounted, by a translation parallel to the first plane P, between at least one relatively low directivity position. , in which this flap 32g or 32d is relatively remote from the connection zone 35g or 35d of the corresponding outlet wall 34g or 34d, and a relatively high directivity position, in which this flap 32g or 32d is relatively close to the zone connecting 35g or 35d of the corresponding outlet wall 34g or 34d, or even resting on this area.

When a flap, such as 32g or 32d, is placed in its relatively low directivity position, represented in solid lines on the figure 3 , the sound waves emerging from the expansion guide 3 are guided by the outlet wall 34g or 34d located on the same side as this flap, this situation being symbolically illustrated by the Figure 4A for both parts at a time.

On the other hand, when a flap, such as 32g or 32d, is placed in its relatively high directivity position, represented in dashed line on the figure 3 , the sound waves emerging from the expansion guide 3 are guided by this flap 32g or 32d, this situation being symbolically illustrated by the Figure 4B for both parts at a time.

Each flap such as 32g or 32d is for example substantially planar and forms with the median plane M an angle A3 of between 20 degrees and 40 degrees, preferably between 25 degrees and 35 degrees, and which can be chosen to be equal to 30 degrees.

Furthermore, each flap such as 32g or 32d, for example constituted by a polycarbonate plate, may have, in the corresponding connection zone 35g or 35d, a leading edge 320 ( figures 3 and 6 ) adopting substantially the same orientation as the inlet wall 33g or 33d located on the same side as this flap, and resting on this inlet wall 33g or 33d in the relatively high directivity position of this flap 32g or 32d ( Figure 4B ).

Each loudspeaker such as E1 to E7 preferably comprises two medium frequency sound reproducing sections 12 and two bass sound reproduction sections 13 disposed outside the solid angle of emission of the sound waves and symmetrically by ratio to the median plane M.

For example, each medium-frequency sound reproducing section 12 consists essentially of a loudspeaker mounted on a wooden panel forming at least part of the input wall, such as 33g or 33d.

Similarly, each section 13 of bass sound reproduction is for example essentially consisting of a loudspeaker mounted on a wooden panel forming at least a portion of the outlet wall, such as 34g or 34d.

Under these conditions, each inlet wall 33g or 33d can be considered physically constituted both by the corresponding wood panel and by the membrane of the corresponding medium frequency loudspeaker, the direction of this input wall being assimilated to that of this wooden panel.

Similarly, each outlet wall 34g or 34d may be considered physically constituted both by the corresponding wood panel and the corresponding bass sound speaker membrane, the direction of this output wall being comparable to that of this wooden panel.

In the preferred case where the flaps 32g and 32d are movable independently of one another, they can not only adopt a symmetrical configuration of high directivity as shown by the Figures 4B , 5A and 7A and a symmetrical configuration of weak directivity as shown by Figures 3, 4A , 5B and 7B , but also a first asymmetrical configuration illustrated at Figures 5C and 7C and in which the flap 32d is in the low directivity position while the flap 32g is in the high directivity position, and a second asymmetrical configuration illustrated in FIGS. Figures 5D and 7D and in which the flap 32g is in the low directivity position while the flap 32d is in the high directivity position.

The figure 6 illustrates a mechanism usable, among many others, to maintain the flaps 32g and 32d and to allow movement between their low and high directivity positions.

Such a mechanism comprises for example two mutually parallel slides 4H and 4B, the slide 4H being fixed by its ends on the upper front edges 51H and 52H ( figure 5D ) of the shell or the frame 5 of the enclosure E1, and the slideway 4B being fixed by its ends on the lower front edges 51B and 52B ( figure 5D ) of that hull or chassis 5.

Each shutter such as 32g and 32d is furthermore equipped, on its upper and lower edges, with respective slides, such as 61H, 61B, 62H, 62B, rigidly fixed to this flap and holding it in an angular position determined with respect to the plane. going through the slides.

Each of the slides, such as 61H, 61B, 62H, 62B, further comprises two pins such as 611H, 612H, 611B, 612B, 621H, 622H, 621B, and 622B, aligned along the length of the slides 4H and 4B.

These lugs are engaged and made prisoners in respective slots, such as 41H, 41B, 42H, 42B, which are formed in the slides 4H and 4B, and wherein these lugs are slidably mounted between two extreme positions.

Claims (9)

1. Sound system at least composed of a first acoustic enclosure (E1) fitted with at least one section (11) for reproducing high-pitch sounds, a section (12) for reproducing middle-frequency sounds, and a wave-expansion guide (3), the guide (3) having an input (30) on which it receives the sound waves generated by a transducer (20) of the section (11) for reproducing the high-pitched sounds, and an output (31) on which the sound waves emerging from this guide (3) are spread in a transmission solid angle, this guide (3) also having, extending transversely to a first plane (P), two entry walls (33g, 33d) that are symmetrical relative to a mid-plane (M) perpendicular to the first plane (P), two exit walls (34g, 34d) themselves symmetrical relative to the mid-plane (M), and two movable flaps (32g, 32d), the entry walls (33g, 33d) forming between them a first angle (A1) and the exit walls (34g, 34d) being connected respectively to the entry walls (33g, 33d) in respective connection zones (35g, 35d) and forming between them a second angle (A2) more open than the first angle (A1) and giving the guide (3), at least in projection in the first plane (P), a shape opening out from its entry (30) to its exit (31), the movable flaps (32g, 32d) being able to be moved by a movement made parallel to the first plane (P) in order to give to the transmission solid angle a value capable of being adjusted by movement of these flaps (32g, 32d), characterized in that this first enclosure (E1) comprises two sections (12) for reproducing sounds of medium frequency respectively placed against the two entry walls (33g, 33d), outside of the transmission solid angle, and in that each movable flap (32g, 32d) is placed at least partially inside the second angle (A2), facing a corresponding exit wall (34g, 34d), and bordered, on the side of the entry (30) of the guide (3), by a leading edge (320) that can be moved relative to the corresponding connection zone (35g, 35d), each flap thus being able to selectively adopt, independently of the other flap, a position close to or a position far from the corresponding exit wall (34g, 34d).
2. Sound system according to Claim 1, characterized in that the first enclosure (E1) comprises at least one section (13) for reproducing low-pitched sounds placed against one of the two exit walls (34g, 34d), outside the transmission solid angle.
3. Sound system according to Claim 2, characterized in that the first enclosure (E1) comprises two sections (13) for reproducing low-pitched sounds respectively placed against the exit walls (34g, 34d), outside the transmission solid angle.
4. Sound system according to any one of the preceding claims, characterized in that the section (11) of high-pitched sounds comprises a waveguide (21) connecting the transducer (20) to the entry (30) of the expansion guide (3).
5. Sound system according to Claim 4, characterized in that the waveguide (21) has, facing the entry (30) of the expansion guide (3), an exit (210) in the form of a slot oriented in a direction substantially transversal to the first plane (P).
6. Sound system according to any one of the preceding claims, characterized in that each flap (32g, 32d) forms a non-zero angle with the corresponding exit wall (34g, 34d) and is mounted so as to be able to move, by translation parallel to the first plane (P), between a position of relatively low directivity, in which the leading edge (320) of this flap (32g, 32d) is relatively distant from the connection zone (35g, 35d) of the corresponding exit wall (34g, 34d) and in which the sound waves emerging from the expansion guide (3) are guided by the corresponding exit wall (34g, 34d), and a position of relatively high directivity, in which the leading edge (320) of this flap (32g, 32d) is relatively close to the connection zone (35g, 35d) of the corresponding exit (34g, 34d) or resting on this zone (35g, 35d) and in which the sound waves emerging from the expansion guide (3) are guided by this flap (32g, 32d).
7. Sound system according to Claim 6, characterized in that the leading edge (320) of each flap (32g, 32d) adopts substantially the same orientation as the entry wall (33g, 33d) to which the corresponding exit wall (34g, 34d) is connected and resting on this entry wall (33g, 33d) in the position of relatively high directivity of this flap (32g, 32d).
8. Sound system according to any one of the preceding claims, characterized in that the first angle (A1) is between 35 degrees and 55 degrees, preferably between 42 degrees and 48 degrees, in that the second angle (A2) is between 100 degrees and 140 degrees, preferably between 115 degrees and 125 degrees, and in that each flap (32g, 32d) forms, with the mid-plane (M), an angle (A3) of between 20 degrees and 40 degrees, preferably between 25 degrees and 35 degrees.
9. Sound system according to any one of the preceding claims, characterized in that it also comprises at least one second acoustic enclosure (E7) similar to the first (E1) and forming, at least with the first enclosure (E1), a one-dimensional network (LSA) of sound sources extending in a direction substantially transversal to the first plane (P), the second enclosure (E7) comprising movable flaps (32g, 32d) that can be moved independently of the movable flaps (32g, 32d) of the first enclosure (E1).

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