Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
  • H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
  • H04R1/345—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means for loudspeakers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/02—Casings; Cabinets ; Supports therefor; Mountings therein
  • H04R1/025—Arrangements for fixing loudspeaker transducers, e.g. in a box, furniture
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/22—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired frequency characteristic only 
  • H04R1/30—Combinations of transducers with horns, e.g. with mechanical matching means, i.e. front-loaded horns
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R1/00—Details of transducers, loudspeakers or microphones
  • H04R1/20—Arrangements for obtaining desired frequency or directional characteristics
  • H04R1/32—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only
  • H04R1/34—Arrangements for obtaining desired frequency or directional characteristics for obtaining desired directional characteristic only by using a single transducer with sound reflecting, diffracting, directing or guiding means
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R7/00—Diaphragms for electromechanical transducers; Cones
  • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
  • H04R7/12—Non-planar diaphragms or cones
  • H04R7/127—Non-planar diaphragms or cones dome-shaped
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R7/00—Diaphragms for electromechanical transducers; Cones
  • H04R7/16—Mounting or tensioning of diaphragms or cones
  • H04R7/18—Mounting or tensioning of diaphragms or cones at the periphery
• • 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
  • G10K11/26—Sound-focusing or directing, e.g. scanning
  • G10K11/28—Sound-focusing or directing, e.g. scanning using reflection, e.g. parabolic reflectors
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
  • H04R2201/34—Directing or guiding sound by means of a phase plug
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R2400/00—Loudspeakers
  • H04R2400/11—Aspects regarding the frame of loudspeaker transducers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
  • H04R2400/00—Loudspeakers
  • H04R2400/13—Use or details of compression drivers

Definitions

• the invention relates to a reverberating sound diffusion enclosure, that is, an enclosure for projecting sound waves onto a reflecting surface, typically a ceiling or wall of a room.
• the invention relates more particularly to an enclosure in which the crosstalk is high between the sound waves obtained by reverberation and those projected in front of the enclosure.
• the invention finds a particularly advantageous application for home cinema installations, cinemas, or music listening rooms for which it is desired to spatialize the sound waves in a room.
• This solution makes it possible to simulate the positioning of a speaker on a wall or a ceiling.
• the audience instead of receiving the sound waves coming directly from a speaker oriented towards the audience, the audience can also receive one or more sound waves obtained by reverberation on a reflection surface by means of a speaker distant from this surface. reflection.
• a reverberation sound diffusion speaker 100 is placed on the floor 40 in front of a screen, not shown, of a home cinema room.
• the enclosure 100 includes a speaker 110 oriented towards the ceiling 41 so as to transmit the sound waves by reverberation on the ceiling 41 of the home cinema room.
• crosstalk corresponds to the ratio between the sound Sr picked up by the audience by reverberation and the sound Sd picked up coming directly from the speaker.
• this crosstalk can be measured by a microphone 42, as shown in Figure 1.
• the propagation time of sound waves obtained by reverberation is greater than the propagation time of sound waves transmitted directly from the loudspeaker of the enclosure.
• the presence of sound waves transmitted directly therefore disturbs the listening quality of sound waves obtained by reverberation and it is sought to limit the direct transmission of sound to improve crosstalk.
• the acoustic energy radiated by the loudspeaker weakens in proportion to the square of the distance traveled.
• the loudspeaker must provide much greater acoustic energy than to obtain direct propagation.
• the smaller sized loudspeakers are less directional and they pose diffraction and acoustic breakdown problems which deteriorate the acoustic performance.
• a waveguide 120 on the loudspeaker 110 in order to limit the propagation of the sounds Sd, as illustrated in FIG. 1.
• a guide wave 120 it is necessary to limit the tilt angle ⁇ between the loudspeaker and the length of the enclosure box in order to obtain an acceptable level of crosstalk with a small loudspeaker.
• the tilt angle al of a small footprint enclosure is close to 70 °, which limits the possible distance between enclosure 100 and the audience.
• a small enclosure is conventionally placed less than 2m from the audience so that the sound waves obtained by reverberating on a ceiling reach the audience correctly.
• the technical problem of the invention is to find how to improve the crosstalk of a sound diffusion speaker by reverberation, in particular for speakers of small dimensions.
• the invention proposes to use at least one acoustic wall integrated in the waveguide to improve the performance of the waveguide.
• the invention is the result of a discovery resulting from the observation that the highest frequencies are not correctly picked up by the waveguide in the context of a sound diffusion enclosure by reverberation.
• the invention has required extensive studies to determine how to modify the directivity of the high frequencies generated by the loudspeaker of a reverb sound diffusion enclosure.
• acoustic walls of very different shapes and positions were tested. It emerges from these studies that the crosstalk is improved in a very surprising way when at least one acoustic wall is fixed on the lateral uprights of the waveguide and that this acoustic wall extends tangentially with respect to the generating line of the cylindrical support. speaker closest to a front panel of the speaker.
• the invention relates to a sound diffusion enclosure by reverberation comprising:
• a membrane an annular outer edge of which is connected to an upper bearing surface of said frame by means of a suspension and an annular inner edge which is fixed to said cylindrical support;
• a waveguide mounted on said upper bearing surface of said frame, said waveguide having substantially the shape of a truncated pyramid with a wall of great length, a wall of short length and lateral uprights connecting said walls ; said long wall forming a front face of said enclosure so that said long wall blocks the propagation of sound in front of said enclosure so that most of the sound is directed towards a reflecting surface.
• the invention is characterized in that said waveguide also comprises at least one acoustic wall fixed to said lateral uprights, said acoustic wall extending tangentially with respect to the line generating said cylindrical support closest to said front face.
• the modification carried out on the waveguide makes it possible to improve the crosstalk of a sound diffusion enclosure by reverberation by channeling the high frequencies generated by the enclosure.
• the enclosure can be made in a box on which said speaker and said waveguide are fixed, said box having a height of less than 14cm, a length of less than 28cm and a width of less than 18cm.
• the improved crosstalk also reduces the tilt angle of the speaker relative to the length of the cabinet.
• the inclination of the loudspeaker relative to a length of the box means that the axis of the loudspeaker passing through the center of the cylindrical support is offset relative to an axis extending along the length of the box. , for example an axis directed towards a predetermined point of listening.
• the invention makes it possible to place the enclosure at a distance of between 3 and 4.5m.
• the speaker can be less close to the audience, which also limits the installation constraints.
• the same principle applies for a speaker projecting sound onto a wall.
• the upper surface of the cylindrical support is preferably provided with a dome, for example an inverted dome.
• an inverted dome corresponds to a dome whose curvature is oriented towards an interior part of the fixed frame.
• said waveguide also comprises a second acoustic wall fixed between said lateral uprights and between said first acoustic wall extending tangentially with respect to the generating line and said front face, said second acoustic wall extending substantially parallel to said first acoustic wall with a distance between said acoustic walls substantially equal to the radius of said cylindrical support.
• This specific positioning of the second acoustic wall makes it possible to efficiently channel the intermediate frequencies between the high frequencies, picked up by the first acoustic wall, and the low frequencies, picked up by the waveguide.
• said acoustic wall extending tangentially with respect to the generating line comprises a semicircular lip extending in the direction of said cylindrical support substantially at the center of said lateral uprights.
• This embodiment further improves crosstalk by channeling the highest frequencies, generated as close as possible to the speaker, onto the first acoustic wall.
• the invention thus makes it possible to obtain an enclosure for diffusing sound by reverberation, of small dimensions, and having significant crosstalk.
• the invention relates to a home cinema installation incorporating a speaker according to the first aspect of the invention.
• Figure 1 is a schematic sectional view of a state-of-the-art reverberation sound diffusion speaker implemented in a home cinema installation;
• Figure 2 is a schematic sectional view of a sound diffusion speaker by reverberation, according to a first embodiment of the invention, implemented in a home cinema installation;
• Figure 3 is a schematic sectional view of a speaker and a waveguide according to a second embodiment of the invention.
• Figure 4 is a schematic sectional view of the first acoustic wall of the waveguide of Figure 3;
• Figure 5 is a schematic sectional view of the second acoustic wall of the waveguide of Figure 3;
• Figures 6a-6f are sectional views of the loudspeaker and waveguide of figure 3 for different frequencies generated by the loudspeaker: 100Hz (figure 6a); 1 kHz ( Figure 6b); 2kHz (figure 6c); 5kHz (Figure 6d); 10kHz (figure 6e) and 16kHz (figure 6f).
• Figures 6a-6f are sectional views of the speaker and waveguide of Figure 3 for different frequencies generated by the speaker: 100Hz ( Figure 6a); 1 kHz ( Figure 6b); 2kHz (figure 6c); 5kHz (Figure 6d); 10kHz (figure 6e) and 16kHz (figure 6f).
• Figures 6a-6f are sectional views of the speaker and waveguide of Figure 3 for different frequencies generated by the speaker: 100Hz ( Figure 6a); 1 kHz ( Figure 6b); 2kHz (figure 6c); 5kHz (Figure 6d); 10kHz (figure 6e) and 16kHz (figure 6f).
• Figures 6a-6f are sectional views of the speaker and waveguide of Figure 3 for different frequencies generated by the speaker: 100Hz ( Figure 6a); 1 kHz ( Figure 6b); 2kHz (figure 6c); 5kHz (Figure 6d); 10kHz (figure 6e) and 16kHz (figure 6f).
• Figures 6a-6f are sectional views of the loudspeaker and waveguide of the FIG. 3 for different frequencies generated by the loudspeaker: 100Hz (FIG. 6a); 1 kHz (Figure 6b); 2kHz (figure 6c); 5kHz (Figure 6d); 10kHz (figure 6e) and 16kHz (figure 6f).
• Figures 6a-6f are sectional views of the speaker and waveguide of Figure 3 for different frequencies generated by the speaker: 100Hz (Figure 6a); 1 kHz (Figure 6b); 2kHz (figure 6c); 5kHz (Figure 6d); 10kHz (figure 6e) and 16kHz (figure 6f); [Fig 7a] Figure 7a is a first perspective view of the speaker and waveguide of Figure 3;
• Figure 7b is a second perspective view of the speaker and waveguide of Figure 3;
• Figure 7c is a third perspective view of the speaker and waveguide of Figure 3.
• Figure 7d is a fourth perspective view of the speaker and waveguide of Figure 3.
• FIG. 2 illustrates a speaker for broadcasting sound by reverberation 10 integrated into a home cinema room.
• the enclosure 10 is placed on the floor 40 in front of a screen, not shown.
• the enclosure 10 comprises a loudspeaker 11 oriented towards the ceiling 41 of the cinema room so as to use the ceiling 41 as a reflecting surface for the sound waves emitted from the loudspeaker 11.
• the nature of the surface reflection can vary without changing the invention.
• the speaker 10 can be arranged on the ceiling 41 using the floor 40 as a reflecting surface or the speaker 10 can be turned up by a 90 ° angle to use a wall in the home theater room as a surface. reflection.
• the loudspeaker 11 comprises a frame 12 fixed inside a box 30 forming the external dimensions of the enclosure 10.
• the box 30 has a height of less than 14 cm, a length of less than 28 cm and a width less than 18 cm.
• the power of the loudspeaker 11 is substantially 250 Watts.
• the orientation of the loudspeaker 11 with respect to the box 30 makes it possible to adjust the angle of inclination al and, thus, the distance traveled by the sound waves obtained by reverberation between the enclosure 10 and the audience.
• the angle a1 between an axis of revolution Ar of the loudspeaker 11 and an axis extending along the length of the box 30 is between 40 and 60 degrees, and preferably between 50 and 52 degrees.
• the frame 12 supports a motor for driving a membrane 14.
• the loudspeaker 11 comprises a cylindrical support 13 movable in translation by means of the magnetic field generated by the motor, not shown.
• This cylindrical support 13 is connected to the membrane 14 by an inner annular edge 18 of the membrane 14 fixed to an upper end of the cylindrical support 13.
• the relative terms “upper” or “lower” refer to the conventional positioning of a loudspeaker as illustrated in FIG. 3 in which the motor is arranged in the lower part while the membrane 14 is arranged in the lower part. upper part of the loudspeaker 11.
• the loudspeaker 11 can be turned upside down without changing the invention.
• the annular outer edge 15 of the membrane is for its part connected to an upper bearing surface 16 of the frame by means of a suspension 17.
• the frame 12 extends from the base of the loudspeaker 11 to its upper end by surrounding the cylindrical support 13 and the membrane 14.
• the cylindrical support 13 preferably has an upper surface 28 provided with a dome, for example an inverted dome.
• the upper bearing surface 16 of the frame 12 preferably has a diameter of between 5 and 15 centimeters.
• this upper bearing surface 16 also makes it possible to mount a waveguide 20 also fixed inside the box 30.
• This waveguide 20 has a substantially truncated pyramidal shape with a wall.
• front of great length 21 is a rear wall of short length 22.
• References to the relative terms “front” and “rear” are understood in relation to Figure 2 in which the front part of the enclosure 10 is the part intended to be positioned close to the audience while the rear part of the speaker. enclosure 10 is the part intended to be positioned farthest from the audience.
• the loudspeaker 11 can be arranged differently without changing the invention but, in all cases, the front wall of great length 21 forms a front face Fa of the enclosure 10 as regards the propagation of the sound waves. .
• the crosstalk is measured at the level of the audience, for example by a microphone 42, by means of the ratio Sr to Sd between the sound Sr picked up by the audience by reverberation and the sound Sd picked up by the audience coming directly from the speaker 10.
• the very long wall 21 limits the propagation of direct sound waves Sd to promote reception by the audience of sound waves Sr obtained by reverberation on the ceiling 41.
• the walls 21 and 22 of the guide d 'wave 20 are connected by lateral uprights 23.
• the opening angle of the waveguide 20, that is to say the angle of inclination a2 of the various walls 21 to 23 of the waveguide 20 from the upper bearing surface 16 of the frame 12, is preferably between 5 and 10 degrees.
• the long front wall 21 may have a length of between 12 and 20 cm, preferably between 14 and 15 cm.
• the rear wall of short length 22 may have a length of between 0 and 5 cm.
• the waveguide 20 may have a flap intended to allow the fixing of the waveguide 20 on the box 30.
• the invention proposes to improve the waveguide 20 by integrating at least one acoustic wall 25 fixed between the side uprights 23.
• the enclosure 10 comprises a single acoustic wall 25.
• the waveguide 20 incorporates a second acoustic wall 26. This embodiment of Figure 3 is also shown in perspective in Figures 7a to 7d.
• the first acoustic wall 25 is fixed between the side uprights 23. It can extend over the entire height of these side uprights 23 to form a substantially trapezoidal plate. As a variant, the height of this acoustic wall 25 can extend over only part of the height of the vertical uprights 23.
• this first acoustic wall 25 extends substantially tangentially to a generating line Dg of the cylindrical support 13.
• the cylindrical support 13 has an axis of revolution Ar around which a set of generating lines form the various points of the cylinder.
• the generating line Dg closest to the front face Fa constitutes the line on which the first acoustic wall is formed.
• the line Dg passes substantially through the center of the trapezoidal shape of the first acoustic wall 25.
• the lower part of the first acoustic wall 25 is provided with a semicircular lip 25 extending in the direction of the cylindrical support 13 and substantially in the center of the side uprights 23.
• a second acoustic wall 26 is also fixed between the two lateral uprights 23 over only part of the height of these lateral uprights 23, as illustrated in FIG. 5.
• the distance DI between the first 25 and the second 26 acoustic wall is preferably substantially equal to the radius R of the cylindrical support 13.
• the second acoustic wall 26 extends along an axis A2 parallel to the axis of revolution Ar and on the generating line Dg.
• Figures 6a to 6f show sound wave propagation simulations of the embodiment of Figure 3. As illustrated in Figure 6a, for a 100 Hz sound wave, the entire surface of the membrane 14 is used to generate the sound waves and the front face Fa of the waveguide 20 is sufficient to guide the sound waves towards the ceiling 41.
• the second acoustic wall 26 captures part of the sound waves generated by the loudspeaker 11 to redirect them towards the ceiling 41.
• the generation of the sound waves is very localized in the center of the membrane 14.
• the second acoustic wall 26 becomes inoperative and it is the first acoustic wall 25 which guides the acoustic waves towards the ceiling
• the invention proposes to modify a waveguide 20 of a speaker 10 for diffusing sound by reverberation in order to improve crosstalk.
• This improvement in crosstalk makes it possible to reduce the angle of inclination ⁇ 1 of the loudspeaker 11 and, thus, to place the enclosure 10 further away from the audience in order to reduce the installation constraints of the enclosure 10. It follows that the invention makes it easier to form a home cinema or a musical listening room.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Signal Processing (AREA)
• Health & Medical Sciences (AREA)
• Otolaryngology (AREA)
• Multimedia (AREA)
• Obtaining Desirable Characteristics In Audible-Bandwidth Transducers (AREA)
• Details Of Audible-Bandwidth Transducers (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=70738660

Family Applications (1)

Country Status (5)

Family Cites Families (11)

• 2019
  • 2019-12-24 FR FR1915555A patent/FR3105692B1/fr active Active
• 2020
  • 2020-12-21 CN CN202080090030.XA patent/CN114930872B/zh active Active
  • 2020-12-21 EP EP20851218.6A patent/EP4082222A1/fr active Pending
  • 2020-12-21 US US17/787,374 patent/US11627411B2/en active Active
  • 2020-12-21 WO PCT/FR2020/052576 patent/WO2021130441A1/fr unknown

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