Classifications

• • G—PHYSICS
  • G10—MUSICAL INSTRUMENTS; ACOUSTICS
  • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
  • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
  • G10K11/18—Methods or devices for transmitting, conducting or directing sound
  • G10K11/20—Reflecting arrangements

Definitions

• the invention relates to an acoustic reflector.
• Acoustic reflectors are particularly used in theaters, such as concert halls, opera or theater, or in rehearsal rooms or recording studios.
• the wave produced inside a room is reflected on the different walls, formed in particular by the floor, the walls and the ceiling.
• Sound regardless of the medium in which they are propagated, undergo reflections on the walls or panels that surround them.
• the characteristics of these reflections depend on many parameters: the shape and the modenature, the material of the reflecting walls, the thickness of these walls, the material located at the rear of the reflecting walls, the sound level of the source.
• reflections in the space defined by the room constitute the spatio-temporal characteristics of the acoustic field. Spatial characteristics are defined by the distribution of acoustic energy in space and temporal characteristics are defined by the distribution of acoustic energy over time.
• a sound source emits so-called source waves, reflected a first time on a wall.
• the waves thus reflected form the primary reflections.
• These reflected waves will themselves be reflected on other walls, one or more times.
• the subsequently reflected waves thus form the secondary reflections.
• the human ear primarily uses the time between the original sound and the primary reflections to determine the size of the surrounding area, while the secondary reflections indicate the type and complexity of the environment in which the listener is. as well as its distance to the transmitting source.
• Direct waves and multiple reflections form the acoustic field.
• the spatio-temporal characteristics of this one determine the way in which the listener perceives the sounds emitted in the room.
• each vibrating wall constitutes an additional acoustic source superimposed on the source waves and the reflected waves.
• the phenomenon of vibration can cause audible noise and thus annoy including musicians. This phenomenon must be avoided.
• the phenomenon of reflection the incident waves are reflected, without preferential direction.
• the absorption phenomenon this assumes that a part, or almost all of the incident wave, is absorbed.
• Figures 1 to 3 show the waveform 1 reflected by a reflector 2 of pyramidal shape, respectively for a source or incident wave of low frequency, medium frequency and high frequency.
• the waveform 1 is a three-dimensional diagram representing the intensity of acoustic waves reflected by a wall or a solid as a function of their direction of reflection.
• lobes 3 appear, the latter representing areas of high intensity of the reflected waves. It can be seen that these lobes 3 are of the same intensity and are oriented in opposite directions. In this case, the waveform does not have a privileged direction.
• the invention aims to remedy all or part of these disadvantages by proposing a diffuser to ensure an oriented diffusion of acoustic waves.
• the invention relates to an acoustic reflector, characterized in that it comprises a structure comprising a plurality of spacers spaced relative to each other, connected by a plurality of cross members spaced relative to each other, the sleepers being distributed so that the structure has at least a first area having a high density of sleepers and at least a second area having a low density of sleepers.
• This type of diffuser makes it possible to ensure diffusion of the acoustic waves, while conferring on the reflected and diffused waves a particular preferred orientation. Indeed, the reflected wave will tend to be directed towards the area of lower density of sleepers.
• the spacing between two adjacent ties of the first zone increases progressively, as said sleepers of the first zone are close to the second zone, the distance between two sleepers of the second zone gradually decreasing, as and as said sleepers of the second zone are close to the first zone, so as to ensure a progressive and continuous distribution of the sleepers along the structure.
• the structure has, on the side of a volume to which the sound must be reflected, a general shape concave, convex or wavy.
• the concave, convex or corrugated zone has a radius of curvature of between 1 meter and 10 meters.
• the structure has a generally planar shape.
• At least part of the structure is covered, on the opposite side to the volume to which the sound is to be reflected, at least one acoustic reflection plate.
• the acoustic reflection plate is made of wood or plaster.
• This type of material makes it possible to amplify the phenomenon of reflection and to increase the reverberation.
• the acoustic reflection plate is made of fiberglass cloth.
• This type of material makes it possible to absorb part of the incident wave, and thus to limit the effect of reverberation due to the multiplicity of echoes reflected by walls and objects. It is recalled that when the reverberation of the sound is too great inside the volume, speech intelligibility and sound reproduction are difficult to control.
• the rails and / or sleepers are made of wood.
• the longitudinal members and / or the crosspieces have a height of between 22 and 40 mm and a thickness of between 10 and 100 mm.
• the height is defined as the distance along the axis normal to the structure and the width as the distance along the tangent plane of the structure.
• Figure 1 to 3 are views showing the waveform of a pyramidal-shaped acoustic reflector, respectively for incident waves at low, medium and high frequencies.
• Figure 4 is seen in perspective and from below, an acoustic reflector of generally wavy shape
• Figure 5 and a side view of the reflector of Figure 4
• Figure 6 is a top view of the reflector of Figure 4;
• Figure 7 is a perspective view from below of a reflector of Figure 4, in which the shape of the reflected and scattered wave is shown;
• Figure 5 is a view of a rehearsal room equipped with a reflector of Figure 4;
• FIGS. 9 to 12 are views respectively corresponding to FIGS. 4 to 7, of a reflector of FIG. 4 equipped with reflection and / or absorption plates.
• FIGS. 13 to 16 and 17 to 20 are views respectively corresponding to FIGS. 4 to 7 and 9 to 12, of a generally concave reflector
• 21 to 24 and 25 to 28 are views respectively corresponding to Figures 4 to 7 and 9 to 12, a reflector of generally convex shape;
• Figure 29 and 30 are views respectively corresponding to Figures 6 and 7, a reflector of generally planar shape.
• FIGS. 4 to 8 An embodiment of a reflector 4 is shown in FIGS. 4 to 8.
• This reflector 1 comprises a structure of generally wavy shape, comprising a plurality of wooden crosspieces 5 spaced apart from one another, refitted by a plurality of longitudinal members. 6 wooden apart from each other.
• the corrugated shape defines a vertex 7 and a recess 8, said structure further having an upper surface 9, intended to be turned towards a ceiling 10 and a lower surface 11, intended to be turned towards the interior of a theater or repetition.
• the spacing of the crosspieces 5 varies according to their position. More particularly, the sleepers 5 are distributed so that the structure has one or more areas having a high density of sleepers and at least one or more areas having a low density of sleepers.
• the zones of high density are situated at the level of the vertex 7 and the hollow 8, the low density zones being located at the ends 14 of the structure and in a median zone 15 of the -this.
• each high density zone increases progressively as said cross members of the high density zone are close to the low density zone (s).
• the spacing between two crosspieces 5 of each low density zone gradually decreases, as said cross members 5 of the low density zone are close to the high density zone or zones.
• the arrangement of the crosspieces 5 is made in a progressive and continuous distribution thereof along the structure.
• the zones of high density are slightly off-center of the axis A of the vertex 7 and of the axis B of the recess 8, this decentration favoring the orientation of the wave reflected in a preferential direction, as is better described. below.
• the spacing between the crosspieces 5 is between 10 and 100 mm, in areas of small spacing and is between 100 and 500 mm, in areas of high spacing.
• the radius of curvature of the structure 4 is between 1 m and 10 m.
• the cross members 5 and / or the longitudinal members 6 have a height of between 22 and 40 mm and a thickness of between 10 and 100 mm. The height is defined as the distance along the axis normal to the structure 4, and the width as the distance along the tangent plane of the structure 4.
• the reflected waves 1 are scattered in all directions, but that the waves thus diffused are oriented preferentially along the axis or the plane P (FIG. 7). More particularly, we note that the shape of the wave 1 tends to move towards the zone of greater spacing, that is to say of lower density, sleepers 5.
• the upper surface 9 can be equipped with reflection or diffusion plates 12, covering all or part of cells 13 delimited by the crosspieces 5 and the longitudinal members 6.
• the acoustic reflection plates are made of wood, plaster or fiberglass cloth, especially in a material marketed under the trademark "Acoustis 50".
• the orientation of the waveform 1 is not substantially modified.
• the reflector 4 has a generally concave shape, facing downwards. Elements similar to those described above have been designated by the same references.
• the areas of lower density of the crosspieces 5 are located at the ends 14 of the structure, the zone of higher density of the crosspieces 5 being located at the hollow 8 formed by the concavity. More particularly, the zone of higher density is slightly off-center with respect to the axis B of the hollow 8.
• the structure may be equipped with reflection or acoustic absorption plates 12, as shown Figures 17 to 20.
• the reflected and scattered waves 1 are oriented preferentially towards the zone of more low density of the crosspieces 5.
• Figures 21 to 24 and 25 to 28 show similar embodiments to those respectively described in Figures 13 to 16 and 19 to 20, the structure however having a convex shape, facing downwards.
• the zone of higher density of the crosspieces 5 is centered on the axis A of the vertex 7 of the structure, formed by the convexity.
• the reflected and scattered waves 1 are oriented preferentially in two directions P 1 , P2, directed on either side of the symmetry plane of the structure. As before, this orientation is directed towards the low density lateral zones, that is to say of greater spacing of the crosspieces 5.
• Figures 29 and 30 show an embodiment similar to that described in Figures 4 to 7, the structure however having a planar shape.
• the crosspieces 5 may have larger dimensions than the longitudinal members 6.
• the reflected and diffused waves 1 are substantially directed in a zone normal to the zone of greater spacing of the cross members, delimited on both sides. other by areas of smaller gauge.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Acoustics & Sound (AREA)
• Multimedia (AREA)
• Building Environments (AREA)
• Aerials With Secondary Devices (AREA)
• Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

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Family Cites Families (5)

• 2008
  • 2008-11-20 FR FR0806501A patent/FR2938687B1/fr active Active
• 2009
  • 2009-11-17 EP EP09768205A patent/EP2347406A1/fr not_active Withdrawn
  • 2009-11-17 CN CN200980146330.9A patent/CN102216981B/zh not_active Expired - Fee Related
  • 2009-11-17 WO PCT/FR2009/052199 patent/WO2010058120A1/fr active Application Filing
• 2011
  • 2011-06-17 MA MA33954A patent/MA32908B1/fr unknown

Non-Patent Citations (1)

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