RU2597656C1 - Dynamic loudspeaker with flat corrugated and cellular membrane - Google Patents

Abstract

FIELD: acoustics.

SUBSTANCE: invention relates to acoustics, particularly to electrodynamic loudspeakers. Loudspeaker has a rigid frame whereto permanent magnet, sound forming membrane on the upper suspension, lower centering diaphragm and voice coil on the frame. Membrane represents a relief surface in the form of alternating ledges and recesses and/or cellular array in form of a disc with parallel planes. Sound forming membrane has sufficient for mechanical transfer and uniform distribution of vibration load along the whole surface of the membrane at connection with the voice coil frame. Sound forming membrane connection with the frame of the voice coil is realized via the central part of the membrane, and/or middle part of the membrane, and/or peripheral part of the membrane. Sound forming membrane along the perimeter is equipped with a corrugated or cellular element made in a form of a circle and attached to the upper suspension. Recesses are made in the form of concentric or radial corrugations. Membrane is connected with upper suspension by gluing through the ring. Projection height of the membrane is 1/15-1/20 of its diameter. Corrugation sides are conjugated to 110-130°. Recesses of the membrane are closed annular convex inserts.

EFFECT: technical result is high sound quality.

17 cl, 16 dwg

Description

The invention relates to the field of electroacoustics, in particular to electrodynamic loudspeakers, and can be used in all cases where high quality sound reproduction is required, namely for sounding of halls, studios, cinemas, in first-class household acoustic equipment, in the field of low and medium frequencies.

A dynamic loudspeaker (DG) is a device that converts low-frequency electrical vibrations into sound.

A known dynamic loudspeaker containing a rigid body to which a magnetic system with a voice coil (ZK) is attached in the gap of the magnetic system, and a sound-reproducing diffuser attached to the diffuser through the upper suspension and centering washer (Shifman D.Kh. Loudspeakers. M .: Energy, 1965, p. 25-26). The diffuser is made in the form of a conical funnel. The dimensions of the diffuser - the outer diameter and depth of the funnel - determine the electrical power and the range of reproduced sound frequencies.

Depending on the range of sound frequencies, DGs are divided into types: low-frequency (LF ≈ 30-2000 Hz), broadband (BW ≈ 60-10000 Hz), mid-frequency (MF ≈ 100-8000 Hz) and high-frequency (HF ≈ 5000-20000 Hz) .

When applying an electrical impulse to the voice coil, the outer and inner sides of the diffuser transmit a dynamic impulse by their movement to the adjacent layer of air, creating a sound impulse propagating in the form of an air wave at a speed of ≈340 m / s. Considering that a dynamic impulse is transmitted to air simultaneously by the entire surface of the sides of the diffuser, not one air wave is created, but an array of waves with a thickness equal to the depth of the diffuser funnel. In this case, a single sound pulse from the extreme depth points of the diffuser occurs simultaneously. As a result of this, the wave pulse propagates not in the form of a thin sphere with a thickness equal to the movement of the diffuser, but “thick”, determined by the depth of the funnel. Reaching the listener's ears, an array of sound waves is perceived for a time equal to the length of the sound travels a distance equal to the depth of the funnel.

Given that the depth of the funnel diffusers is from 1.5 cm (midrange low power) to 7 cm and above (midrange and high power bass), the sound time of one sound pulse is approximately 0.5 to 20 ms. As a result of the above, the quality of the perceived sound is deformed - it is heard fuzzy (blurry) and unnatural.

To improve the sound quality of the DG, numerous searches are being conducted in different directions. In particular, it is known from the technical level to achieve an improvement in sound quality, which is achieved by reducing non-linear distortions. For this, in an acoustic system containing a housing with a loudspeaker and a vibration-damping element placed in it, the latter is made in the form of a honeycomb structure consisting of triangular prisms connected by throttle openings. The loudspeaker is installed in a honeycomb design without a diffuser. The numerical values of the diameter D of the diffuser, the wall thicknesses of the prism and the housing S, the radius R of the throttle hole and the height h of the cross section of the triangular prism are selected in accordance with the ratios h / S = 50-60; D / S = 1000-1200; S / S = 1-10; D / R = 20-30 (RU application for invention No. 93043957, M. cl. H04R 1/28, G10K 13/00, publ. 06/10/1996).

A disadvantage of the known device is that the head diffuser is loaded with additional elasticity of the air volume inside the design. The presence of additional elasticity leads to an increase in the resonant frequency of the moving head system in a closed design and, as a result, to a narrowing of the reproduced frequency range from below.

Improving the sound quality is also possible when changing the shape of the sound-forming surface of the DW by reducing the depth of the funnel of the diffuser with the transition from the diffuser to the membrane. Ideally, it is a membrane with a flat surface.

The closest in technical essence to the proposed solution is a low-frequency loudspeaker with a flat diffuser containing a diffuser, a diffuser suspension, a magnetic system and an oscillating coil (RF patent No. 2523094, M. class. H04R 7/02, publ. 20.07.2014). Moreover, the suspension of the diffuser is made axisymmetric, and the rear main radiation passes at least 50% through the inner part of the magnetic system. The thickness of the diffuser at the outer diameter is more than 10% of the diameter of the diffuser, and the ratio of the diameter of the oscillating coil to the diameter of the diffuser is at least 0.75: 1. The diffuser is designed as a diffuser of a low-frequency speaker, moreover, this system additionally has a loudspeaker for reproducing upper audio frequencies. At least one area of the diffuser is made of elastic foam material, and the diffuser is made three-layer. The core material of the three-layer diffuser has a cellular structure made of aramid fibers, paper, nomex, aluminum, plastic, polyester, polypropylene, and / or contains outer layers of fibrous materials, metal foil and / or plastic film.

The implementation of the proposed DG could eliminate the above disadvantages of analogues, however, the embodiment of the prototype design is currently very problematic due to the lack of materials with the necessary properties.

It is theoretically known that such a material should have a density equal to the density of air, be absolutely rigid and have an absolutely linear suspension, which in reality is impossible to achieve. The materials for manufacturing a flat diffuser listed in the patent are already widely used in the manufacture of diffusers, but only of a traditional funnel shape. In such a design, it is easier to ensure an optimal combination of two fundamental and conflicting properties of materials such as maximum rigidity and internal attenuation over the entire sound-forming surface of the diffuser. In the proposed design of a flat diffuser without special measures ensuring uniform acceleration of the entire surface of the diffuser, it is impossible to obtain high-quality sound reproduction of frequencies that go beyond the piston mode of its operation (400-600 Hz). However, even in this range, the reproduced sound power will be limited by the size and weight of the magnetic system (i.e., the cost of the DG). The ratio of the diameter of the oscillating coil to the diameter of the diffuser adopted in the patent will also be a limiting factor in increasing the size and power of the DW, as it will lead to an increase in the weight of the voice coil itself to values excluding the reproduction of the mid-frequency sound range.

Thus, the design of the invention of the prototype in the presented form will not be able to provide high-quality sound reproduction in the claimed sound range without additional technical solutions that guarantee uniform rigidity over the entire surface of the flat sound-forming membrane and its optimal combination with internal damping. In addition, the design of the voice coil and magnetic system will be a limiting factor in increasing the size and power of the DW.

The objective of the invention is to expand the arsenal of known devices for reproducing high-quality sound.

Technical results that can be obtained using the invention are:

- minimization of the thickness of the array of sound waves from a single electric pulse by replacing the traditional diffuser in a DW with a practically flat membrane;

- achieving uniform stiffness over the entire surface of the sound-forming membrane and its optimal combination with internal damping.

The consequence of their implementation is to improve sound quality by increasing the clarity of sound and increasing the naturalness and localization of sound sources in the space of an audio image.

The solution of this problem and the achievement of the above results became possible due to the fact that in the known dynamic loudspeaker containing a rigid frame to which a permanent magnet is attached, a sound-forming membrane on the upper suspension, a lower centering diaphragm, a voice coil on the frame, in accordance with the proposed solution, a sound-forming membrane is an almost flat relief surface in the form of alternating protrusions and depressions formed as a result of corrugation of the material (g throat membrane), and / or a cellular array in the form of a disk with flat parallel surfaces (cellular membrane) having a rigidity sufficient to mechanically transmit and evenly distribute vibration load over the entire surface of the sound-forming membrane when connected to the voice coil frame through the central part of the membrane, and / or the middle part of the membrane, and / or the peripheral part of the membrane, while the sound-forming membrane around the perimeter is equipped with a corrugated or cellular element made in the form of a circle for attachment to erhnemu suspension.

The claimed solution is complemented by private distinctive features that contribute to the achievement of the claimed technical result.

In a sound-forming corrugation membrane, alternating protrusions and depressions are made in the form of concentric, or radial, or concentric and radial corrugations.

A sound-forming membrane made of concentric corrugations is connected to the upper suspension via gluing on the outer side of the corrugation of the peripheral part of the membrane.

A sound-forming membrane of concentric and radial corrugations is connected to the upper suspension by gluing through a flat ring that contours the radial corrugations at an angle of 55-65 ° to the plane of the sound-forming membrane.

In a sound-forming membrane made with concentric and radial corrugations, the ratio of their areas is 0.3-0.5.

The height of the protrusion of the sound-forming membrane is 1 / 15-1 / 20 of its diameter.

The sides of the corrugation are interconnected at an angle of 110-130 °.

The hollows of the sound-forming membrane can be closed by annular convex inserts.

A sound-forming membrane in the form of a cellular disk is an array of two parallel layers of paper (or other special materials), interconnected by ribs of the same material, forming a cellular structure, contoured in the central part by the voice coil frame, and on the periphery by an external edge in the form of a circle with an annular horizontal strip - a cellular element connected to the upper suspension by gluing.

The height of the ribs (membrane thickness) is 1 / 15-1 / 25 of the diameter of the membrane, and the maximum distance between them in the cell is 0.8-1.3 of the height of the ribs, depending on the stiffness of the material.

The sound-forming membrane can be combined from concentric and cellular arrays, while the ratio of their areas is 0.3-0.5 with a preferred arrangement of the cellular array around the periphery as more rigid.

To facilitate the sound-forming membrane, the lower plane of the cellular disk can be perforated, while the diameter of the holes is 0.8-1.2 of the height of the ribs, depending on its rigidity, and the perforation area of 0.2-0.5 of the total area of the lower plane. For this purpose, the reference diffuser can also be perforated.

The central part of the sound-forming membrane is connected to the upper part of the voice coil frame by gluing.

The middle part of the sound-forming membrane is connected to the middle part of the voice coil frame through a reference diffuser with an opening angle of 100-130 °.

The peripheral part of the sound-forming membrane with insufficient material rigidity or its large sizes can be connected to the lower part of the voice coil frame additionally through a segmented diffuser with a segment area of 25-30% of its total surface or through rods or plates of light and hard material with their fastening the lower part to the voice coil frame along the line of its connection with the centering diaphragm, and the upper part to the peripheral part of the sound-forming membrane, in the amount of 3-5 pcs., the width of the plates with It is not less than 10 mm with a longitudinal bend of variable radius.

The invention is shown in the following drawings:

FIG. 1 - an array of sound waves during transmission of a dynamic pulse of a DW.

FIG. 2A - sound-forming membrane made in the form of concentric corrugations, side view; in FIG. 2B - the same, top view.

FIG. 3A - sound-forming membrane made in the form of radial corrugations, side view; in FIG. 3B - the same, top view.

FIG. 4A - sound-forming membrane is combined in the form of concentric and radial corrugations, side view; in FIG. 4B - the same, top view.

FIG. 5A - a sound-forming membrane made in the form of a cellular disk, side view; FIG. 5B - the same, top view.

FIG. 6A - a sound-forming membrane is combined in the form of concentric corrugations and a cellular array, side view; in FIG. 6B - the same, top view.

FIG. 7A is a photograph of DG 4 ″, in which the sound-forming membrane is made in the form of concentric corrugations and is fixed through a segmented diffuser, side view; in FIG. 7B - the same, bottom view.

FIG. 8A is a photograph of DG 5 ″, in which the sound-forming membrane is made in the form of concentric corrugations and is fixed through the reference diffuser and peripheral rods, side view; in FIG. 8B - the same, top view.

FIG. 9A is a photograph of DG 5 ″, in which the sound-forming membrane is made in the form of concentric corrugations and is fixed through the frame of the ЗК and peripheral rods, and is equipped with ring inserts, side view; in FIG. 9B - the same, top view.

FIG. 10A is a photograph of DG 5 ″, in which the sound-forming membrane is made in the form of concentric and radial corrugations and is fixed through a reference diffuser and rods, side view; in FIG. 10B - the same, top view.

FIG. 11A is a photograph of DG 5 ″, in which the sound-forming membrane is combined in the form of concentric corrugations and a honeycomb array and is fixed through the ZK frame and reference diffuser, side view; Fig 11B is the same, top view.

FIG. 12A is a photograph of a 5 ″ DG, in which the sound-forming membrane is made in the form of a cellular disk and is fixed through the SC frame and the reference diffuser, in FIG. 12B - the same, top view.

FIG. 13A is a photograph of DG 6.5 ″, in which the sound-forming membrane is made in the form of concentric corrugations and is fixed through the ZK frame and rods, side view; in FIG. 13B - the same, top view.

FIG. 14A is a photograph of DG 12 ″, in which the sound-forming membrane is made in the form of concentric corrugations and is fixed through the frame of the ZK and plates, side view; in FIG. 14B - the same, top view.

FIG. 15A is a photograph of DG 15 ″, in which the sound-forming membrane is made in the form of concentric corrugations and is fixed through the frame of the ЗК and plates, side view; on figb - the same, a top view.

FIG. 16 - amplitude-frequency characteristic of a 5 ″ DG with a cellular membrane in the near field (20 cm).

List of Keys

Rigid frame DG 1;

Permanent magnet 2;

Lower centering diaphragm 3;

Sound-forming membrane 4;

Top suspension 5;

Voice coil 6;

Voice coil frame 7;

Alternating projections 8;

Alternating troughs 9;

Cellular array (disk) 10;

Flat parallel surfaces of the mesh disc 11;

Corrugated peripheral element 12;

Cellular peripheral element 13;

Concentric corrugations 14;

Radial corrugations 15;

Cell edge 16;

Reference diffuser 17;

Rods 18;

Plates 19;

Convex inserts 20;

Segment diffuser 21.

The inventive dynamic loudspeaker includes a rigid frame 1, to which a permanent magnet 2, a lower centering diaphragm 3, a sound-forming membrane 4 on the upper suspension 5 and a sound coil 6 on the frame 7 are attached. The sound-forming membrane 4 is made in the form of a practically flat relief surface of alternating protrusions 8 and depressions 9 formed as a result of corrugation of the material or the honeycomb array 10 in the form of a disk with flat parallel surfaces 11. The sound-forming membrane 4 is mechanically connected to the voice coil h Through its frame 7, the central part (D), and / or the middle part (E), and / or the peripheral part (F) for uniform distribution of stiffness and vibration load on the membrane surface. A sound-forming membrane 4 is surrounded by a corrugated element 12 or a cellular element 13 in the form of a circle through which is attached to the upper suspension 5. A sound-forming membrane 4 is made of alternating concentric corrugations 14 or radial corrugations 15, or of a cellular disk 10 or is made in combination of concentric corrugations 14 and from radial corrugations 15, or from concentric corrugations 14 and part of the cellular array 10.

The height of the protrusions 8 of the sound-forming membrane 4 is minimized by optimizing the number of corrugations and is in the ratio 1 / 15-1 / 20 to the diameter of the membrane 4. The sides of the concentric corrugations 14 or radial corrugations 15 are mated to each other at an angle of 110-130 ° without any rounding to increase rigidity.

The sound-forming membrane 4 with radial corrugations 15 is contoured around the perimeter by the corrugation element 12 in the form of a flat ring connected along the plane with the external beveled ends of the corrugations and creating the rigidity of the peripheral part (F). The angle of inclination of the flat ring to the plane of the sound-forming membrane 4 is 55-65 °.

The thickness of the cellular disk 10 is determined by the height of the ribs of the cell 16 and is 1 / 15-1 / 25 of the diameter of the membrane, and the maximum distance between the ribs is 0.8-1.3 of the height, depending on the rigidity of the material.

The uniform distribution of vibration over the surface of the membrane 4 depending on the rigidity of the corrugated material is ensured by the mechanical connection of the membrane 4 with the frame 7 of the voice coil 6:

- through the central support by making the voice coil frame high enough to adhere its upper part to the mating central part (D) of the membrane 4;

- through the middle support by installing a reference diffuser 17 with an opening angle of 100-130 °, the lower part of which is connected to the middle part of the voice coil frame 7, and the upper part is connected with the corrugation or the lower plane of the cellular disk in the middle part (E) of the membrane 4 .

With a low rigidity of the corrugating material or a large diameter of the sound-forming membrane 4, in addition to the middle and / or central support, peripheral supports are installed that are attached by the lower part to the voice coil frame 7 along the line of its connection with the centering diaphragm:

- in the form of a segmented diffuser 21 (Fig. 7) with a segment area of 25-30% of its total surface, depending on the stiffness of the material;

- in the form of rods 18 or plates 19 (Fig. 14) made of light and hard material with their lower end fixed to the voice coil frame 7 along the line of its connection with the centering diaphragm 3, and the upper part to the corrugated element 12 or the cellular element 13 peripheral parts of the membrane 4 in the amount of 3-5 pcs., depending on the rigidity of the material. The width of the plates is 10 mm or more with a longitudinal bend along a variable radius, ensuring the coupling of their ends with the surface of the frame of the ZK and the peripheral elements of the membrane. Plates are used for large-sized DG (low-frequency range)

The location of the central and middle supports is determined constructively from the ratio of the areas of the central and peripheral parts of the membrane 4 from 0.3-0.5 along the line C of the connection of the middle support with the corrugation or the lower plane of the cellular massif.

In a sound-forming membrane with concentric corrugations 14 and radial corrugations 15, the latter are preferably peripheral, as more rigid. The ratio of the areas of alternating protrusions and depressions of the sound-forming membrane, made in the form of concentric and radial corrugations, is 0.3-0.5.

In order to further reduce the deformation of perceived sound in the corrugation membrane, the troughs 9 of the corrugations are closed by annular convex inserts 20, which, when optimizing the number and height of the corrugations, allows to obtain an almost flat sound-forming membrane.

It is still generally accepted that with constant progress in the use of new materials for the manufacture of DG diffusers, paper remains an unsurpassed material for high-quality sound reproduction in the midrange.

In the design of medium-frequency DWs, banknote paper was used as the material for the manufacture of the sound-forming membrane, but other material intended for speaker cones can also be used. For example, a composition based on sulfite bleached pulp and sulfate unbleached pulp. For the manufacture of a sound-forming membrane of low-frequency DWs, the material of their directly diffusers was used.

The choice of banknote paper is justified by the density, high strength and rigidity of its array, the presence of watermarks simulating a cellular structure. This is also facilitated by the multilayer technology of the fibrous skeleton of cotton plant fibers (up to 50%) and flax, arranged randomly, and the use of special sizing agents.

Thus, real constructive solutions of DWs have been developed with the replacement of the traditional diffuser with an almost flat membrane in the form of a corrugated array (corrugated membrane), in which the AB distance decreases to 5-6 mm, and when overlapping corrugations of the corrugations with ring inserts, up to 2-3 mm in midrange speakers and up to 10-15 mm in woofers, which is practically lower than the ear sensitivity threshold for the duration of perception of a sound array of such thickness. Real constructive solutions of DW with an almost flat cellular sound-forming membrane (cellular membrane), in which the distance A-B is reduced to zero, have also been developed.

Claims (17)

1. A dynamic loudspeaker comprising a rigid frame to which a permanent magnet is attached, a sound-forming membrane on the upper suspension, a lower centering diaphragm, a voice coil on a frame, characterized in that the sound-forming membrane is an almost flat relief surface in the form of alternating protrusions and depressions, formed as a result of corrugation of the material and / or the cellular array in the form of a disk with parallel planes, having rigidity sufficient for mechanical transmission and equal the distribution of vibration over the entire surface of the membrane when it is connected to the voice coil frame through the central part of the membrane, and / or the middle part of the membrane, and / or the peripheral part of the membrane, while the sound-forming membrane around the perimeter is equipped with a corrugated or cellular element made in the form of a circle and attached to the upper suspension. 2. The dynamic loudspeaker according to claim 1, characterized in that the alternating protrusions and depressions of the corrugated sound-forming membrane are made in the form of concentric, or radial, or concentric and radial corrugations. 3. The dynamic loudspeaker according to claim 1, characterized in that the sound-forming membrane of concentric corrugations is connected to the upper suspension via gluing the outer side of the corrugation of the peripheral part of the membrane. 4. The dynamic loudspeaker according to claim 3, characterized in that the sound-forming membrane of radial and concentric and radial corrugations is connected to the upper suspension by gluing through a flat ring that contours the radial corrugations at an angle of 55-65 ° to the plane of the sound-forming membrane. 5. The dynamic loudspeaker according to claim 2, characterized in that the ratio of the areas of alternating protrusions and depressions of the sound-forming membrane, made in the form of concentric and radial corrugations, is 0.3-0.5. 6. The dynamic loudspeaker according to claim 1, characterized in that the height of the protrusion of the sound-forming membrane is 1 / 15-1 / 20 of its diameter. 7. The dynamic speaker according to claim 1, characterized in that the sides of the corrugation are interconnected at an angle of 110-130 °. 8. The dynamic loudspeaker according to claim 1, characterized in that the sound-forming cellular membrane is made of two planes of sheet material interconnected by ribs of the same material. 9. The dynamic loudspeaker according to claim 8, characterized in that the thickness of the cellular membrane is determined by the height of the ribs of the cells and is 1 / 15-1 / 25 of the diameter of the membrane, and the maximum distance between them is 0.8-1.3 of height. 10. The dynamic loudspeaker according to claim 1, characterized in that the cellular membrane is bonded by bonding with the upper suspension through a cellular element in the form of a rib with an annular strip that outlines the membrane around the periphery. 11. The dynamic loudspeaker according to claim 1, characterized in that the lower plane of the mesh disk and the reference diffuser are perforated, the diameter of the holes being 0.8-1.2 of the height of the rib depending on its rigidity, and the perforation area of 0.2-0 , 5 of the total area of the lower plane. 12. The dynamic loudspeaker according to claim 1, characterized in that the central part of the sound-forming membrane is connected to the upper part of the voice coil frame by gluing. 13. The dynamic loudspeaker according to claim 1, characterized in that the middle part of the sound-forming membrane is connected to the middle part of the voice coil frame through a reference diffuser with an opening angle of 100-130 °. 14. The dynamic loudspeaker according to claim 1, characterized in that the peripheral part of the sound-forming membrane is connected to the lower part of the voice coil frame through a segmented diffuser with a segment area of 25-30% of its total surface or through rods or plates of light and hard material with fixing their lower part to the voice coil frame along the line of its connection with the centering diaphragm, and the upper part to the peripheral part of the sound-forming membrane, in the amount of 3-5 pcs., while the width of the plates is at least 10 mm with bending along a variable radius. 15. The dynamic loudspeaker according to claim 1, characterized in that in the sound-forming membrane made with concentric and radial corrugations or concentric corrugations and a cellular array, the ratio of their areas is 0.3-0.5. 16. The dynamic loudspeaker according to claim 1, characterized in that the troughs of the sound-forming membrane are closed by annular convex inserts. 17. The dynamic loudspeaker according to claim 1, characterized in that banknote paper is used as a material for corrugation in a medium-frequency DG.

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