KR20000075889A - Acoustic device - Google Patents

Abstract

The acoustic device of the present invention extends in the transverse direction of the thickness and generates a bending wave that generates an acoustic action by the resonance mode spatial distribution of the original bending wave oscillation on the surface consistent with the acoustic action that can be achieved in the appropriate operating acoustic frequency range. And a retainable member. The stiffness spatial distribution, including the flexural stiffness variation, is intended to obtain the proper position of the flexural wave transducers from inadequate members and to achieve good resonant acoustic behavior. It features a combination of piston-type drive and flexure excitation at the center of mass and geometry.

Description

Sound device {ACOUSTIC DEVICE}

In joint international application GB96 / 02145, a general description of the nature, structure, and construction of acoustic panel members capable of maintaining and transmitting input vibration energy through flexural waves at (but not necessarily) thick acoustic operating areas extending to the edge of the member is required. Initiated knowledge. And a resonant vibrating element distributed throughout the area, particularly suitable for acoustic coupling with ambient air, with or without anisotropic bending strength penetrating / passing the area; In addition, various specific panel configurations were also analyzed in which the acoustic transducer means, in particular, the acoustic vibration response in the area and in particular in relation to the electrical signal, had a decisive position corresponding to the acoustic magnitude of the vibration response in the area in an effective operating or moving part. . “Passive” sound devices without transducer means for reverberation or acoustic filtration or acoustic “voicing” in any space or room; In addition, a member of an "active" acoustic device having a wide-range loudspeaker as a sound source when supplied with an input signal to be converted to sound and a bending wave transducer means included in a microphone or the like when exposed to a sound to be converted into another signal. The use can also be found in the PCT application on.

The UK patent application (P.5840) is based on the use of mechanical impedance characteristics to achieve precision with respect to the geometry or position of flexural transducer means for panel members in acoustic devices and the like. The contents of the above applications and PCT applications are referred to for the understanding of the present invention.

This invention relates in particular to a loudspeaker type active acoustic device (also referred to as a distributed acoustic radiator / resonance panel, described below) which employs a panel member which is implemented as described above and which satisfactorily combines the bending wave action and the piston action. do. However, more general and broader aspects of the present invention have been discovered.

(Summary of invention)

Firstly, the present invention relates to a flexural wave action in a panel member, in particular, a realization position in a flexural wave transducer means different from that disclosed in the above PCT and UK patent applications, ie in the PCT application, in particular an object that is not offset. It relates to active sound devices which can provide different parts, including center and geometric positions.

Secondly, the present invention specifically relates to an acoustic device according to a bending wave action in a panel member that provides an effective distribution of resonant vibrations showing different results, even with the same configuration or geometry as described in the PCT application and the UK application. .

Thirdly, the present invention specifically relates to acoustics due to flexural waves in panel members that provide resonant vibrations of effective distribution in panel members of different configurations and geometries than those introduced as advantageous in the context of the PCT applications and UK applications. Pertains to the device.

An effective embodiment of the present invention is based on the simple excitation of the inherent spatially distributed acoustic wave effect for acoustic manipulation, and thus the spatial distribution of the resonant vibratory element of acoustic function effect, which is generally similar to the PCT application and UK application. Using a panel member with a unique function to provide a; In general, when selectively suppressing or generating vibration in a unique panel member or providing various frequency ranges, as in the PCT application and the UK application according to other specific structures and the like, the resonant action of the intrinsic distribution is specific. Indeed, depending on the design requirements, no method of modifying other acoustical actions in the panel member which is inadequate for the geometry or position of the transducer means is not used.

Preferred methods and means of the present invention involve a spatial distribution of intensity variations in at least some area of the acoustically active panel member with respect to flexural wave action and desired acoustical manipulation. This change is directly related to the displacement of the transducer means from the positions described in the PCT and UK applications at each position of the invention, or the space of the resonant vibration due to the bending wave action of an improper configuration or geometry panel member. It may be caused by the distribution, or by the various spatial distributions of the flexural strength, the location for the transducer means, or both, to make them closer to the configuration or geometry desired for acoustic manipulations with somewhat different actual resonant distributions.

The contents of the PCT application can be decomposed in two coordinate directions or along these coordinates over the whole or part of the acoustic range of the panel member, and can be extended and applied to panel members having flexural strength in various directions of constant size. In contrast, the preferred panel member in the embodiment cannot be decomposed constantly in standard coordinates or there is a change in flexural strength along a particular direction in the operating range lying in any direction.

The spatial variation in flexural strength can thus be easily achieved by varying the thickness of the acoustic panel members, but in addition, the thickness and density or tensile strength of the skin of the sandwich-type structure or of a single structural stiffener made of synthetic resin can also be a cause. have.

In the panel member, it is almost impossible to conduct a conventional analysis to accurately and completely confirm and quantify the actual spatial distribution change of the acoustic resonance vibration, and in the corresponding direction in the specific isotropic or anisotropic embodiment in the PCT application. Even with similar geometries and average intensities-it is not possible to determine whether there is a function to improve this if the current acoustic function with the bending wave action is not successfully achieved or if there is a big obstacle. The basic configuration / geometry of the PCT application and the UK application (on the spatial distribution of resonant vibrations) can be maintained to the extent that the two groups are very useful in view of the above.

As already exemplified, Group 1 provides a more suitable location for transducer means in an acoustic panel member having a configuration or geometry which is particularly preferred in isotropic or anisotropic embodiments such as the PCT application and the UK application. This is achieved by displacing the "original" position of the transducer means (in the above application) by one or more flexural strengths which increase or decrease from one to the other or to a specific position embodied by said original position. A zone of greater flexural strength shifts its original position away from this zone, usually on the other hand, or to a zone of smaller flexural strength. ; Zones with lower flexural strength move to the original zone. Other groups may contribute in part to the formation of at least conceptual quasi-geometries of larger overall panel member geometries that are not particularly desirable for good distributed acoustic manipulation, such as in PCT applications and UK applications. ; These semi-geometries are incomplete and of no particular importance per se, but partial definitions with good effect on distributed acoustic manipulation tend to be configurations or geometries with certain advantages if they do not achieve the above advantages; This improvement is partly due to the distribution of the resonance at low frequencies, but it is not necessary to limit the bending wave action and the resonance distribution of the larger frequencies, i.e., the high frequency resonant vibration distribution is overlying the partial quasi-geometry.

In order to easily achieve the desired spatial variation of the flexural strength panel member, as described in the above PCT and UK applications, at least the core layer also includes a sandwiched composition having a uniform isotropic or anisotropic structure and having a skin layer surrounding the core layer. . The change in thickness is a value that can easily achieve the spatial distribution of strength in a desired form. In the case of deformable materials such as foams, this change in thickness is achieved by selective compression or grinding to achieve the desired shape. That is, it can be carried out after the skin layer is formed while applying heating control and pressure to the desired profile (depending on the stretch properties of the skin layer material). It is also possible, in particular, for members that are locally hardened or weakened by grade. In a draw cell or honeycomb material, that is, a rectangular shape of cells extending from the skin of the ultimate sandwich structure, or a solid shape that is a non-broken composite, the thickness change can be easily achieved by selecting the shape / profile of the desired thickness. Can be achieved. Changes in geometric centers are not necessarily accompanied by changes in mass centers during skimming rather than grinding. In addition, by examining the thickness / strength change in the existing core separately, this can play an important role in the transducer means combining the piston action and the bending wave action because there is no change in the center of mass. In this case, the piston action can be optimally adjusted if it is located concentrically with the center of mass and geometry, with the aim of avoiding differential moments due to mass distribution due to transducer position and unbalanced air pressure effects.

The center of mass is, of course, easily repositioned according to the geometric center, and the mass can be selected in the panel member without negatively affecting the spatial distribution of the desired strength. That is, it refers to a mass of a mass that is appropriately mounted in the cavity of the panel in a small amount that does not adversely affect the low frequency bending wave action without deviating from the high frequency sound action.

When the strength increases in one direction out of the other side of the 'original' position in the transducer positioning means, or decreases in strength in the opposite direction, it becomes the position of the transducer means towards the geometric center in the one direction. The increase / decrease in strength is reduced due to the shape of the panel member as the thickness / strength increase decreases to the edge of the panel member or the thickness / strength decrease is further accelerated and thus the panel member has a uniform edge thickness.

In addition, the characteristic of the present invention in one or more groups is that the acoustic range is not concentric with the center of mass or the geometric center of the panel member even if the position of the acoustic transducer means is concentric regardless of the bending wave action or the piston action. In addition to the distribution of flexural strength in the acoustic wave can be seen in the panel member.

At this point, there are two ways in which the intensity space distribution of the panel member can be regarded as centered, and one of them is to determine the center of mass, which sets the first moment of strength to zero and corresponds to relatively high strength. (Herein referred to as "high center of intensity"); Another one sets the first moment to the inverse of the intensity to zero, which corresponds to low intensity (called "low center"). In the isotropic or anisotropic panel member analyzed in the PCT application, the "high center" and "low center" of strength are virtually concentric and usually concentric with the center of mass and geometry; However, in the case of panel members with the intensity distribution here, "high center" and "low center" are distinguished from each other and are far from the center of mass or the geometric center.

At the effective or theoretical displacement (by the preferred intensity distribution) of the effective position (from the position found in the content and analysis of the PCT and UK applications) for the flexurally acting transducer means, the displacement is in the "low center" direction of intensity. It can be observed and thus away from the "high center" direction of strength, which can be oriented in the same direction as the desired theoretical displacement or provide a structural design reference point that will change the flexural strength in the corresponding distribution. In the "low center" the bending strength changes in the direction of the panel member edge in question and usually increases in various sizes and speeds in several directions towards the "high center".

The sandwich structure of the honeycomb core is characterized by its ability to have the desired intensity distribution due to the changed individual cell geometry and does not significantly affect the distribution and center of mass. Thus, the spatial distribution of the desired intensity depends on variations in arbitrary cell cross-sectional area (or shape), cell height (effective core thickness) and cell wall thickness, and the progression depends on the desired increase / decrease. The flexural strength can be varied without disturbing the mass distribution. This can be achieved by changing the cell wall thickness and cell height for the same cell area, and also the cell area and cell height for the cell wall thickness. It can be increased or affected by skin changes, including changes.

In addition, the panel member of the present invention has been shown to have the "low center of gravity" of the most efficient drive position and strength which usually opposes in terms of minimum and maximum diffusion of the transition time to the panel edge with respect to the apparent or actual bending wave. Low center of gravity and the transducer position.

In the second aspect described above, a panel member having an intensity distribution (referred to as "eccentric") is an efficient acoustic flexure that the panel has a particular shape (i.e., configuration or geometry) that cannot be achieved for a particular shape by the known art. Applicable to show wave action; It is also possible not only for the inadequate shape related to the known appropriate shape, but also for the shape which can be processed so as to have a characteristic of at least an appropriate shape irrelevant thereto.

Indeed, the present invention provides a physically feasible spatial distribution of flexural strength even in atypical panel members capable of bending wave acoustics, and provides a resonant characteristic of the distribution appropriate for the above action, even when not conforming to a target shape known to be ideal. It also includes those which can provide particularly effective positions for the wave effect transducer means. Such a procedure should be determined experimentally like trials and trials as a spatial intensity distribution, but it can also be analyzed using finite element methods in providing "low center" and "high center" strengths. This is shown to show a positive (approach / gravity) effect and a negative (distance / repulsion) effect at positions suitable for the transducer means within the spatial intensity distribution, whether or not analytical.

In practice, it is advantageous to find a configuration or modification that can be derived from what is known to be desirable for a particular panel member geometry and structure. In general, this is necessary to display the structural details, especially in panel geometries such as successful spatial intensity distribution and transducer drive positions.

One approach of the present invention focuses attention on the position of the transducer. A method of assuming a panel member of a desired configuration as a target geometry and also a panel member of a target geometry known to be desirable and easily capable of detailed analysis. Through this, the desired target transducer position is placed concentric with the actual and desired transducer position of the target geometry. Therefore, in any selected configuration corresponding to the concentric transducer positions of the target and target geometries through flexural strength mapping, the known geometries of the panel structure can be applied to the deformation corresponding to the target geometries. It is possible to provide the same or similar comparative intensity distribution in the form and the effect of acoustic bending waves in the target geometry. This configuration includes lines starting from the edges of the target and target geometries or from concentric transducer positions through them (referred to as bend wave transmission / crossing). The deformation state varies depending on the relative lengths of the same construction lines in the target and target geometries, and the unit area (μ) is usually used in the proportionality conversion involving the third and fourth powers of the line lengths with respect to the edges of the target and target geometries. There is an appropriate relationship such as flexural strength (B) and mass, i.e., B / μ. For target geometries smaller than the target geometries involved, it is desirable to be more natural and suitable for redundancy to minimize the latter surplus to the former and to minimize the conversion process. In general, while similar types of targets and objects are suitable object geometries that are closest to the desired or inappropriate target geometries, the target geometries have been shown to be quite different from known ideal configurations / structures.

The panel of the PCT application, which is isotropic, studied and analyzed with spatial flexural strength, is the starting point for the object geometry / structure. Indeed, in another structure / transformation approach with a potential value, the transducer position (currently common) involves matching the target geometry / structure according to the manner in which the flexural strength is divided into each face within the target geometry / structure. . Furthermore, not only in various geometries, but also in one kind of target geometry, such as flexural strength distribution, a given geometry / configuration (ie, rectangular or elliptical) actually affects the real space distribution of resonant vibrations, which can be very difficult to inhibit. If it has been proved to be effective, similar or related mapping schemes that mimic other geometries / configurations can be used.

In the loudspeaker members of the piston type and the bending wave action, the concentricity of the bending wave transducer means having the mass and the geometric center is particularly effective to enable the single transducer device to combine and execute the piston drive and the bending excitation in one position.

However, one transducer for piston action only is used concentrically in the mass / geometric center and the other transducer is installed at a suitable distance for bending wave action only. In this case, it is necessary to adjust the mass balance by adding mass (when it cannot be given jointly with the desired flexural strength distribution).

Of particular interest is the possibility of spacing by the position of the flexural transducer (ie, by means of a suitable transducer configuration) or by means of a single transducer providing both piston and flexural wave action at some distance. Another aspect of the invention can be used when retained when application occurs.

In general, the present invention may include a mass distribution having a center of mass displaced from a geometric center or a transducer position. Indeed, the flexural strength and the deformation of the mass can vary in various ways and distributions of the flexural strength and mass, at least in the acoustical operating range of the panel member, and usually vary gradually in a particular direction different from here. It is also common to show anisotropy asymmetrical with respect to the geometric center of mass; As shown in the PCT application.

In a specific aspect of the present invention includes a loudspeaker drive device comprising a chassis, a transducer supported on the chassis, a rigid lightweight panel diaphragm driven by the transducer, and an elastic edge suspension surrounding the diaphragm and mounting the diaphragm in the chassis. The producer produces the audio output by driving the diaphragm in a piston type at a relatively low audio frequency, and also generates the audio output by vibrating and resonating the diaphragm by bending wave action at a high audio frequency. In this assembly, the transducer is coupled to the center of mass / geometric center of the diaphragm and the diaphragm has a flexural strength distribution with deformation (preferably centered away from the center of mass) to effect acoustically resonant action.

The diaphragm is round or oval and the transducer is coupled to the diaphragm's geometric center. The diaphragm includes a lightweight cell core inserted between the opposing skins, one of which extends below the edge of the diaphragm and the end of the extended skin is attached to the elastic suspension.

The transducer is electromagnetic and includes a moveable coil mounted to the coil former, the coil former being driven to the diaphragm. The second elastic suspension is connected between the coil former and the chassis. One end of the coil former is connected to the diaphragm, and the second elastic suspension is disposed adjacent to the end of the coil former and the third elastic suspension is connected between the other end of the coil former and the chassis.

The ends of the coil formers adjacent to the panel diaphragms are coupled to drive the panel diaphragms at one point. A conical means is connected between the coil former and the panel diaphragm to achieve this object.

The coil former includes a flexible section radially diverging from the hard section, which piston-drives the diaphragm and provides the eccentric resonant driving force to the diaphragm.

In another aspect of the invention there is provided a rigid lightweight panel loudspeaker drive unit diaphragm comprising the above-described drive unit or piston driven and oscillating resonance, the diaphragm having a center of mass located at its geometric center and also a stiffness branched from the center of mass. Have a center

The specific embodiments are shown and described in more detail in accordance with the accompanying drawings in which.

The present invention relates to an acoustic device that can acoustically react by a bending wave and can be used in a loudspeaker or the like.

FIG. 1 is a plan view and three diagrams showing that the flexural wave transducers of an acoustic panel member, which are achieved by compressing a strained core material or profiling a core or composite together, are shown in FIGS. Schematic cross section.

Figures 2a, b, c is a schematic overall and core cross-sectional view of the elliptical acoustic panel member.

Figures 3a, b, c is a schematic overall plan view and a core cross-sectional view similar to the above of another elliptical panel member.

4a, b and c show a circular acoustic panel member which is more suitable as a partially elliptical groove / slot and a model distribution graph with or without the groove / slotting treatment.

5A, B, and C are diagrams useful for explaining the mapping / configuration / conversion and also the cross section / profile of the resulting stiffness distribution for the target geometry of the rectangular panel member.

6a, b, c are contour graphs according to the methodology of FIG. 5;

Figure 7a, b is a side cross-sectional view and a plan view of one embodiment of the loudspeaker drive unit of the present invention.

8A and 8B are side cross-sectional views of another loudspeaker drive unit and variations thereof;

9A and 9B are side cross-sectional views of another loudspeaker drive unit and variations thereof;

Figures 10a, b are a perspective view of the loudspeaker drive coupling or actuator to apply the piston action and the bending wave action and a detailed view mounted on the diaphragm / panel member.

11A and 11B show the relationship at the time of intersection with the above operation.

In FIG. 1 (a), the rectangular acoustic distribution panel member 10A has a flexural wave transformer at a position deviated from the position indicated by the diagonal 11 at a position away from the geometric center 12, as described above in the PCT and UK applications. It has a "original" position 13 for the producer means. In the application of the present invention, the transducer position 13 is at the geometric center 12 of the panel member 10A, which appears to be displaced along the solid line 15. This is achieved by appropriate spatial distribution of the flexural strength of the panel member. As a result, the flexural stiffness is on one side of the geometric center 12 (right side of Fig. 1 (a)) and on the opposite side (left side of Fig. 1 (c)) and in the opposite direction of the line 15 side and its It increases or decreases relatively at the " original " transducer position 13 in each of the linear extensions 15G and 15L.

Fig. 1 (b) is a contour on the line 15 including the extensions 15G and 15L and is separated from the geometric center 12B in the same state as Fig. 1 (a), that is, the distributed panel member 10B. Refers to the projection line 12P and 13P. Figure 1 (b) does not include a detailed description of the actual structure of the panel member 10B; A monolithic form like the outer solid lines 16X and Y, or a sandwich-type alternative in which the skin is bonded to the inner core 18 like the inner dashed lines 17X and Y, a conventional foam or a honeycomb through body, etc. are shown.

Fig. 1 (c) is made of various foam materials, particularly suitable for the virtually distributed acoustic panel member in Fig. 1 (c), which is deformable and in particular uses a compressible material core 18C that can be broken into smaller thicknesses. Shows that It can be seen that the thickness of the core 18C decreases from right to left as shown in Fig. 1 (c), and its cell changes from a circular open state (19X) to a flattened (19Y) state. Of course, these cells do not necessarily have to be of similar size or general arrangement or to be opened in a circular shape at the maximum thickness (partially compressed foams are suitable). Core 18C is shown with opposing skins 17A and B. As shown in FIG. Even if it is normal, it may be deformed into a desired profile before it is combined on the skins 17A and B, but if the panel member 10C is not suitable for the distributed acoustical action if it is not compressed with the skins 17A and B, it is essential. no. The thickness increase and decrease of the core 18C and the panel member 10C corresponds to the increase and decrease of the bending stiffness; In addition, the noted strength development profile and stiffness result in concentricity of the geometric center (12C) and transducer position (13C) upon change. See arrow 13S and circles 12C and 13C in the original. Fracture deformation involves thermal resistance and uses pressure plates of appropriate profile. There is no change in the center of mass of the panel member 10C, for example, the center of mass is concentric with the geometric center 12C and also with the transducer position 13C.

When the contribution of the core density is low, i.e., when the flexural stiffness prevails, the appropriate spatial thickness distribution can be achieved by ignoring the linear variable of the core mass contribution.The polymer foam or the structured honeycomb sandwich or single form Shaping the thickness of the isotropic core to achieve the desired spacing distribution; Such structures can also be fabricated or molded.

Fig. 1 (d) shows a distributed acoustic panel member 10D accompanied by a gradual decrease of the bottom surface, which thickness decreases in a profile similar to that of Fig. 1 (c). This profile is somewhat different for the same effect, that is, the effect of positioning the transducer position 13D concentrically with the geometric center 12D, and for example depends on the material used for the panel member 10D. Some materials include honeycomb structures with through cells across the skin, typically in the form of a single reinforcement composite or skinned core. Foam cell form 19Z of FIG. 1 (d) relates to the use of a foam material which is optionally crushed or inadequate for crushing; However, it is only an indication of no significant change in density. Of course, a change in the mass distribution and the center of mass of the panel member occurs, such as falling from the geometric center in the direction of the arrow CM. In order to achieve concentricity of the geometric center 12D and the mass center as a whole, the panel member 10D has an equilibrium 22 located in the blind hole 23, which is a semi-elastic means in a bush or sleeve fixed mechanically or adhesively. The inertial compressor is gradually detached from the panel member 10D at a high frequency of an appropriate vibration distribution. The at least one balance 22 is installed or matrixed less than 180 ° through the extension line 15L and does not have to have the same mass and therefore the mass decreases gradually away from the line 15L.

In short, even if the more complex slope is normal, the thickness slopes or gradually decreases away from the line 15-15G while passing through portions of 1B, including the common same edge thickness (L). It is necessary to consider the geometrical relationship of the bend frequency to the magnitude. In any shape, as the magnitude increases, the fundamental frequency of vibration decreases or vice versa. The shifting effect of the transducer position was found to be equivalent to reducing the panel size for bending in the moving direction.

2A-C and 3A-C, the panel members were all generally elliptical, isotropically (20A) and (30A) appearing to be isotropic and concentric at the geometric center 25 and the mass center 35. In the isomeric panel geometry and structure, the stiffness distribution is centered at (25) and (35) with respect to "high center" (stiffness) or "low center" (ductility or flexibility). In addition, FIGS. 2A and 3A show the most preferable positions 26 and 36 for manipulating the resonant acoustic function of the panel members 20A, 30A, or bending wave action, such as loudspeakers.

2b, c and 3b, c, the center positions of panels 10B, 20B and 30B are denoted by 25, 26 and 35, respectively, and 36 is the geometric center and Corresponding to both centers of mass (25, 35), but now also corresponds to acoustically effective flexural wave transducer positions (26), (36). 2A and 3A, the transducer positions 26 and 36 are effectively displaced by the distribution of flexural stiffness, and the displacements of the "high" and "low" centers of stiffness are generally geometric centers 25, ( (27), (28) and (37) opposite to (35). These different asymmetric stiffness distributions are particularly dependent upon their height, gradual change over the cells 29, 39, as in the panel members thicknesses 20A, 30A and their areas and densities (see Figures 3B, C). Appears to be achieved by ; Alternatively, for their area and wall thickness, except for density (see Figures 2b and c), the desired stiffness distribution can be achieved without large changes in the mass distribution, whereby the center of mass is concentric with both the geometric center and the transducer position ( 25, 26; 35, 36).

A preferred approach to stiffness and subsequent change in area distribution is to provide stiffness in a general way by introducing nonplanar formations, ie, bends or curves; Alternatively, grooves, slots, or notches are formed on the surface along the extension lines 15G and L of FIG. 1 (a) to reduce stiffness or to reduce rib formation to increase the stiffness. (Not shown, but computer computation of finite element method is possible.)

Fig. 4a shows an inner groove for improving the distributed flexural wave action for the acoustic panel member 40 of circular configuration or geometry known to be inadequate, particularly as a distributed acoustic panel member having the center position of the excitation transducer means. Demonstrate the application of digging, slicing or engraving. The existing inadequate performance corresponds in particular to the concentric vibration pattern and is represented by the mode-type frequency distribution of FIG. 4B as will be readily understood by those skilled in the art. The improvement shown in FIG. 4C is not a proper ellipsoid, but also grooved, cracked or etched into a portion of the ellipsoid 45 which belongs to a very good configuration / geometric form, such as a distributed acoustic panel member (see FIGS. 2 and 3). Achieved. However, the effect on low frequency mode action may extend beyond the open end of groove 45. The shape of the groove 45 is realized by the finite element method, like the compound element patterning, which is a common practice technique. The arcuate body asymmetrically separated from the center of the circular panel member is reduced and easily trimmed by the finite element method.

5A and 5B show structures and variations similar to the configurations / geometries of the rectangular targets 51A and B and the objects 52A and B as described above. The construction lines 53A and B treated according to various lengths and flexural stiffnesses have excellent effects when applied to the same rectangular shape. The method of FIG. 5B is particularly effectively constructed from the target configuration / geometry 51B located at this corner by the portion of the target configuration / geometry 52B extending from one corner and thus known transducer position 54B and analysis. The isotropic shaped body 52B simply lies concentric with the geometric center of the target shaped body 51B. FIG. 5C shows a portion passing through the target member 50 of the target shape 51A according to the method of FIG. 5B.

The B / μ index or B or μ parameter value is examined radially (53B) along with other constants, and the mathematical mapping from the shape panel 52B to the panel 51B results in a flexural strength in the direction 53B. Depending on whether it is a sandwich panel or a single solid composite structure without skin, the stiffness distribution can be calculated using a magnification relationship involving four times the length and two or three times the thickness.

FIG. 6A shows a result of measuring a proportional relationship of length mapping in the scheme of FIG. 5B. Figure 6b also shows that the required (target) bending action is the result of the measurement of Figure 6a and also the properties, in particular 4 times the length (solid line), 1/4 the thickness of the sandwich structure (dotted line), and also the thickness of the single structure (seam line). Shows a close relationship with stiffness, such as 4/3 times. In sandwich structures, the skin stiffness (tensile strength) is four times its length; Also, the skin thickness is 4/3 times. FIG. 6C shows the mode density mapping process with 3% damping in the quadrangular target panel member, without distribution of flexural stiffness. The PCT application described that only the difference of one side of the target 1.134: 1 side isotropic panel member was adjusted. In addition, the rectangular panel can be further improved by using the flexural stiffness distribution according to the skin parameters, in particular, the thickness (h) and the Young's modulus (E).

7A and 7B, the loudspeaker drive unit includes a shallow circular basket or an open frame chassis formed in the form of a dish having a perforated outer protruding flange 71F, which results in a baffle (shown in FIG. Can be mounted on a loudspeaker enclosure (not shown) or the like in a conventional manner. The chassis 71 includes a magnet 73 sandwiched between the pole pieces 74A and B and also provides an annular gap to be mounted with a tubular coil 75 former that will form a drive coupling or actuated moving member of the motor. Supports transducers in the form of electric drive motors.

The coil formers are installed on the elastic suspensions 76A and B and both ends guide the coil formers 75 to axially move in the gap of the magnet assembly. One end of the coil former 75 uses a combination 77 to form an acoustic radiator diaphragm of the loudspeaker drive unit, and between the front and rear skins 70F and R, a lightweight cell core 70C made of honeycomb material. It is fixed to the back of the lightweight rigid panel sandwiched in the Panel 70 generally has a flexural stiffness distribution that provides a center of mass and concentricity, and provides a flexural excitation location to the geometric center. With reference to the embodiment, the front skin is generally circular in shape when effectively working with the periphery / suspension or when merging with the cone. The rear skin selects a rectangle to form a composite panel suitable for the distribution (driven directly with the differential coupler of FIGS. 10A and 10B).

When centering the distributed panel section simply, by designing the panel section according to the present invention according to the prior mode distribution by controlling the spatial stiffness, the modal driving point or zone can be located close to the geometry and the center of mass. have. Therefore, in the conventional driver construction and geometry, excellent mode driving at high frequency and piston operation at low frequency are possible.

The front skin 70F of the panel 70 extends below the edge of the panel and attaches the periphery to a suspension 77 or lower surround supported by the chassis 71 to allow the panel to free piston movement. Transducer 72 resonates as in the above length by providing a flexing wave to the panel by vibrating the panel 70 at low frequencies and vibrating at high frequencies.

The assembly arrangements in FIGS. 8A and 8B show that the motor 72 is outside the chassis 81 and the coupler / actuator coil formers 85 are deformed in the chassis with the deformation suspension 86 except when the chassis 81 is a shallower. Extends. A variation of FIG. 9B also includes the use of the small neodymium motor 82N and the sectioned end reduction 85A of the coil former 85.

The assembly arrangement of FIGS. 9A and 9B is similar to FIGS. 8A and 8B except that the extension ends 95A and B of the coil former 95 each include a double conical section, the tip 95P of which is a geometry. Attached to the rear of the lightweight rigid panel diaphragm 90 at the center.

10A and 10B show a diaphragm coupler with a main arcuate perimeter 108 of the drive end 107 to be attached to a lightweight rigid panel 100 of semi-flexible material and also an arch periphery 109 of the same end. The coil generator of the actuator 100, conveniently the drive motor (not shown) is shown. At high frequencies, the coupler / actuator excites the bending wave action by the periphery 109 and thus excites the vibration energy to the panel 100 at a position offset from the axis of the coupler / actuator 105. Because of the semi-ductility, the main arcuate periphery 108 is virtually stationary at high frequencies. Therefore, the actual operating position of the drive varies with frequency even when implemented in the same manner and the same means 105.

The simple view of the direct and semi-flexible parts can extend to a number of fixed contacts and more complex semi-flexible assembly arrangements, ie, two or more distributed panel member transducers can be involved. The semi-flexible part can be graded or graded in terms of thickness and expandability, or divided into multiple stages, and thus the combined stiffness graded according to the panel acoustic performance standard can be graded, thereby providing a geometry center / It is possible to improve the overall function regardless of the distributed acoustic panel having the flexural transducer position away from the center of mass, or the panel suitable for the transducer position of known PCT and UK applications.

The differential frequency coupler 105 has a conventional motor coil used in an electric exciter. The coupler 105 is a separate component of a predetermined dimension or diameter and is suitable for application of a motor coil having a similar diameter as part of the attachment surface, and the frequency response is distributed to the position of one or more pre-drive transducers of the distributed acoustic panel member. It is selected to excite at the rigid end when generated by the bending vibration in the member 100. At low frequencies, the semi-elastic portions / inserts 108 contribute to making the entire environment of the actuator / coupler 105 suitable for equilibrium of the center of mass motion, so that the piston action occurs at low frequencies. The basic bending frequency of the panel member 100 and the elasticity of the coupler / actuator portion 108 can appropriately and flexibly move the acoustic force from the piston type to the frequency range of the bending vibration portion. This movement may also be aided by multistage movement of the component 108 or by oblique movement as in 108A.

Manipulation of the coupler 108 refers to FIG. 11A, which outlines the velocity change applied to the acoustic panel, including the intersection. At low frequencies, the semi-soft section 108 provides power to the panel member 100 in a balanced piston manner. The piston action decays upon increasing frequency when anticipating the mechanical impedance of the vibrating panel member 100 and when excited in an eccentric position. Thus, substantial velocity contributions at high frequencies occur in the rigid offset sector of the coupler.

Figure 11b also shows the distributed excitation position according to the displacement and frequency of the piston drive. At low frequencies, the piston drive point is expected to be center of mass. When the frequency increases, the flexion excitation position moves off center and the panel type, the complex coupler / actuator diameter, and the geometry of the part are appropriately selected and arranged to drive near the proper distribution position when vibrating.

In Figures 7a and b above, the flexural wave transducer means is 150 to 200 mm in diameter and appropriately bends the "original" transducer position of the distributed panel member in the range of 150 Hz to 500 Hz. Piston operation is effective for a suitable acoustic device at lower frequencies, ie 30 Hz, and is reduced in the upper limit as the panel member is in the range of bending operation.

The differential frequency of the coupler of the present invention functions precisely for using a distributed acoustic panel member. For example, changing the drive point from panel to frequency has been found to be suitable for frequency control in close response, as well as close to wall enclosures of small enclosures. One or more grades, sizes, or faces of semi-flexible parts or inserts can be used appropriately for coupler geometries to move them progressively or stepwise between the driving points of a frequency mode pattern and to appropriately modify the radial sound. have.

Claims (52)

A member extending in the transverse direction of the thickness and capable of retaining the bending wave causing the acoustic action by the resonance mode spatial distribution of the original bending wave oscillation at the surface consistent with the acoustic action that can be achieved in the appropriate operating acoustic frequency range On the other hand, the member is of an unsuitable geometry or configuration to achieve the above acoustic action, and the member is also capable of changing the bending stiffness variation related to making the member more suitable for the spatial distribution of the resonance mode for the acoustic action. An acoustic device, characterized in that it has a spatial distribution of bending stiffness. The method of claim 1, Wherein said member has a position determined by a spatial distribution of flexural stiffness for the flexural wave transducer means to cause an acoustic action. A member extending in the transverse direction of thickness and capable of retaining the bending wave causing the acoustic action by the resonance mode distribution of the original bending wave oscillation at the surface consistent with the acoustic action that can be achieved in the appropriate operating acoustic frequency range; And the member has a spatial distribution of flexural stiffness, including a flexural stiffness variation associated with determining the position of the flexural wave transducer means for causing an acoustic action. A member extending transversely in thickness and capable of retaining the bending wave in at least the acoustical operating range of the transverse extension, while said member is in the above-described range consistent with the acoustical action that can be achieved in the appropriate operating acoustic frequency range A flexural stiffness having a parameter of bending stiffness that predetermines the resonant mode distribution of the original flexural wave oscillation at, wherein the flexural stiffness with spatial distribution in the member is related to determining the position for the flexural wave transducer means A sound device comprising a change. The method according to claim 2, 3 or 4, Said bending stiffness change is characterized in that it comprises a large and small bending stiffness for each side of the position of the bending wave transducer means. The method according to any one of the preceding claims, Wherein the bending stiffness change comprises a large and small flexural stiffness for each side of the geometric center or the range of the member. The method of claim 5 or 6, The bending stiffness change is characterized in that it has a high or low virtual center position in various directions with respect to the side. The method according to any one of the preceding claims, And the magnitude of the thickness of the member corresponds to the magnitude of the stiffness of the flexural stiffness distribution, respectively. The method of claim 8, A method for manufacturing an acoustic apparatus, characterized in that the deformation material thickness of the member is selectively reduced. The method of claim 8, And the material of the member is selectively reduced to reduce the thickness. The method according to any one of the preceding claims, And said member comprises relational means for sorting and providing another additional mass that has no effect on sound action. The method of claim 11, And wherein the additional mass is less than a magnitude having a significant effect on low frequency acoustics and includes means associated with the member effective for separating the additional mass for high frequency acoustics. The method of claim 11 or 12, Wherein each mass providing means has an additional mass for the center of mass of said member and there is a mass providing means in a desired position of said member. The method of claim 13, And the desired position is concentric with the geometric center of the member. The method of claim 8, The member has a sandwiched structure with a skin on a core having a cell constituting wall, the wall extending by varying the thickness between the skins when providing a predetermined mass distribution to the member and also forming cells of various cross-sectional sizes. Sound device, characterized in that. The method of claim 8, The member has a sandwiched structure with a skin on a core having a cell constituting wall, wherein the wall extends by varying the thickness between the skins when providing a predetermined mass distribution to the member and also forms cells of varying thickness. A sound device characterized by. The method of claim 15 or 16, And said predetermined mass distribution is centered on the geometric center of said member or range. The method according to claim 1, 2, 3 or 4, Wherein the change in flexural stiffness comprises at least one local cause of the member. The method of claim 18, The local cause is an acoustic device, characterized in that to provide a weakening groove, slot or gap to the member. The method of claim 18 or 19, The local variation in the distribution of flexural stiffness is characterized in that the weakening groove, slot or gap of the member is provided to the member. The method of claim 20, An acoustic device, characterized in that the local variation in the flexural stiffness distribution makes the high frequency type bending wave dependent vibration smaller than the local variation. The method according to any one of claims 1 to 7, Wherein said member is a skin-like structure and multiplies the change in flexural stiffness by a skin parameter. The method of claim 22, A sounding device, characterized in that the thickness is one of the skin parameters. The method of claim 22 or 23, Sound module, characterized in that the module of the zero is one of the skin parameters. In the method for manufacturing a panel member for an acoustic device, The space of the flexural stiffness depends on the displacement of the actual position for the flexural wave transducer means from the apparent position when the member is in a suitable configuration or geometry for the desired acoustic action by the spatial distribution of the resonance mode. And determining the distribution, wherein the change involves a large and small flexural stiffness with respect to the opposing surface of the appropriate actual position and the apparent position. The method of claim 25, Wherein said large and small flexural stiffness runs along a theoretical straight extension through an appropriate position and an apparent position. The method according to any one of the preceding claims, The member is of a suitable configuration or geometry for the desired acoustical action by the spatial distribution of the resonant mode without the spatial distribution of flexural stiffness including the change, and the preferred actual position and position for the flexural wave transducer means of the inappropriate configuration or geometry. When overlapping concentrically with a suitable configuration or geometry flexural wave transducer means, the difference between said inappropriate configuration or geometry and a suitable geometry, as well as the direction and suitable configuration through both configurations or geometries, Manufacturing method characterized in that the bending stiffness change is determined based on the deformation of the bending stiffness in the geometric form. The method of claim 27, Said overlapping position belongs to a nonconforming configuration or geometry completely contained in a suitable configuration or geometry. The method of claim 27 or 28, Said overlapping positions coincide with edges of conforming and nonconforming configurations or geometries. The method of claim 27, 28 or 29, Said suitable structure or geometry is a manufacturing method characterized by the extension from the edge of an actual nonconformity or geometry. The method according to any one of claims 27 to 30, The above deformation is a sandwich type structure of the member, characterized in that the small flexural stiffness progresses along a theoretical straight extension through an appropriate position and an apparent position. 32. An acoustic device comprising a member made according to any of claims 25-31. The method according to any one of the preceding claims, And the position of the bending wave transducer means for causing the acoustic action is used for the piston action acoustic transducer means. The method of claim 33, wherein An acoustic transducer means in said position, said acoustic transducer means acting on the bending wave and the piston. A loudspeaker drive device comprising a chassis, a transducer supported by the chassis, a lightweight rigid panel diaphragm driven and coupled to the transducer, and an elastic edge suspension surrounding the diaphragm and fixing the diaphragm in the chassis. The transducer generates an audio output by driving the diaphragm in a piston type at a low audio frequency, and the assembly is arranged to generate an audio output by vibrating and resonating the diaphragm with a bending wave at a high frequency. Accordingly, the transducer is operated at the center of mass or the geometric center. And a diaphragm connected to the loudspeaker driving apparatus, wherein the diaphragm has a flexural stiffness distribution including a change to enable an acoustic resonance action of the diaphragm. 36. The method of claim 35 wherein Loudspeaker drive device characterized in that the diaphragm is round or oval. The method of claim 35 or 36, And a diaphragm comprising a lightweight cellular core sandwiched between both skins. The method of claim 37, One of said skins extends below the edge of the diaphragm and the distal end of the extended skin is attached to the elastic suspension. The method of any one of claims 35-38, And the diaphragm is a distributed resonance panel. The method according to any one of claims 35 to 39, The transducer is electromagnetic and includes a moving coil installed on the coil former, wherein the coil former is operable coupled to the diaphragm. The method of claim 40, And a second elastic suspension connected between the coil former and the chassis. The method of claim 41, wherein One end of the coil former is connected to the diaphragm, the second elastic suspension is disposed adjacent the end, and the third elastic suspension is connected between the other end of the coil former and the chassis. The method according to any one of claims 35 to 42, And a distal end of the coil former adjacent to the panel diaphragm is coupled to drive the panel diaphragm at one point. The method of claim 43, And a conical means connected between the coil former and the panel diaphragm. A lightweight rigid panel loudspeaker drive diaphragm, characterized in that it is driven by a piston and is oscillated so as to be resonated by a bending wave, and the center of stiffness distribution is located at the geometric center and out of the center of mass. A loudspeaker comprising the drive device according to any one of claims 35 to 44. A loudspeaker drive actuator comprising an offset ductile and rigid drive coupling component for driving a diaphragm centered on one axis in a piston fashion and generating an eccentric resonant excitation to the diaphragm. Offset ductile and rigid drive coupling components for driving a diaphragm centered on one axis by piston type at least one flexible component at low frequency and generating an eccentric resonant excitation to the diaphragm by at least one rigid component at high frequency Loudspeaker drive actuator comprising a. Offset ductile and rigid drive coupling components that excite the vibrations of the diaphragm with a bending wave to drive the diaphragm at low frequency by at least one flexible component and at least one rigid component at high frequency to produce a distributed acoustic action. Loudspeaker drive actuator comprising a. The method of any one of claims 47, 48 or 49, Rigid parts also contribute to the piston drive. The method according to any one of claims 47 to 50, And the part is in the periphery of the tubular member. A loudspeaker drive comprising an actuator according to claim 51, characterized in that the tubular member is fixed to the diaphragm.