GB2215164A

GB2215164A - Loudspeaker having open-filter frame of continuous VV shape in cross section and wave modulation plate of same design

Info

Publication number: GB2215164A
Application number: GB8802815A
Authority: GB
Inventors: Jimmy Fang
Original assignee: Peter Tsung-Hou Fei
Current assignee: Peter Tsung-Hou Fei
Priority date: 1988-03-08
Filing date: 1988-02-08
Publication date: 1989-09-13
Anticipated expiration: 2008-02-08
Also published as: SE8800430L; GB8802815D0; SE466982B; FR2628281A1; FR2628281B1; DE3807472C1; GB1456501A; SE8800430D0; GB2215164B

Description

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BACKGROUND OF THE MENTION

The present invention relates to a loudspeaker.

A typical loudspeaker is an electromagnet surrounded by and attached to a conic body which upon electrical stimulation vibrates. The motions of the conic body are perpendicular, thus two exact contrary sound waves are produced in the surrounding air. If these two contrary sound waves come into contact, mutual destruction occurs, thu, s the main function of the speaker cabinet is to effectively prevent interference between the opposing sound waves. Conventional speaker cabinets are basically of two kinds, being of the infinite-baffle (sealed) variety, and the bass-reflex (ported) variety, each with their associated problems, being in the former variety the conic body receives the interference of negative sound waves generated within the cabinet, suppressing output, and in the latter variety an exaggerated cabinet resonance character produces an inequity of sounds. The present invention comprises a means for effectively countering both of the aforementioned problems by use of a sneaker possessing a uniquely designed frame, or by use of a new type wave modulation plate patterned after such a frame, both of which are especially suitable for use in smallersize speaker cabinets.

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07._ OBJECTS OF THE INVENTION It is an object of the present invention to provide an improved loudspeaker having a uniquely designed frame which is of continuous VV shape in cross section.

It is an additional object to provide such a speaker which has a mearis for effectively reducing the interference of negative sound waves generated within the cabinet, eliminating cabinet resonance problemsi and reducing the distortion in middle and low frequencies such as most commonly occurs in smaller-size cabinets.

It is also an object of the present invention to provide a newly designed wave modulation plate of continuous VV shape in cross section.

It is an additional object to provide such a wave modulation plate which has a means for effectively reducing the interference of negative sound waves generated within a loudspeaker cabinet, eliminating cabinet resonance problems, and reducing the distortion in middle and low frequencies such as most commonly occurs in smaller size cabinets.

It is also an object of the present invention to use the above mentioned uniquely designed loudspeaker frame in combination with the said wave modulation plate such that they are sufficient to provide combined results.

It is an additional object to provide such a wave modulation plate which can effectively restrict the flow of sound while concurrently allowing the free passage of air. and thus can be utilized in television enclosures. converter enclosures and the like.

C, --s-- BRIEF DESCRIPTION OF THf DRAWINGS t Fig. 1 is a view showing the structure of a typical loudspeaker (1) comprised mainly of a frame (2), a sound-producing conic body (3), a yoke (4), a permanent magnet (5), with through holes provided in the frame (5) for sound and air to pasi therethrough.

Fig. 2 shows an embodiment of a loudspeaker having the filtering hole type frame according to the present invention. in which the through holes (V) of the frame (21) are an open-f ilter of continuous VV shapes in cross-section.

Fig. 3 is a front view of an embodiment of a loudspeake: having a partialsection of the filtering hole type frame accoSing to the present invention. It is to be noted that the closed ends (pointed ends) of each VV shape (61) are facing the conic body (TO Fig. 4 is a detail extended plane view of the frame of Fig. 2.

Fig. 5 is an extanded czoss-sectional view along the line of kk' of Fig. 4 in which 1 is greater than b and angle 9 of each Vis less than 90 degrees.

Fig. 6 shows another embodiment of the filtering hole type frame according to the present invention in which the holes of the VV plane are in rectangular conic shapes.

Fig. 7 shows another embodiment of the filtering hole type frame according to the present invention in which the holes of the VV plane are in the shape of hives.

Fig. 8 shows another embodiment of the filtering hole type frame according to the present invention in which the holes of the VV plane are in round shapes.

Fig. 9 is a view showing a possible arrangement of the loudspeaker according to the present invention in which the wave modulating plate (8) of VV configuration is mounted in a cabinet with the drawing on the left.

cl q Lt showing the VV shape in enlarged scale. It is to be noted that the closed ends (pointed ends) of the shapes face the sound-producing conic body of the loudspeaker.

Fig. 10 is a cross-sectional view of the wave modulating plate according to the present invention.

Fig. 11 is a view showing a possible arrangement in the loudspeaker cabinet of Fig. 9 in which multi-layers of the wave modulating plate of VV configuration are used.

Fig. 12 is a view showing an arrangement using an inverted filtering hole type (in AA shape)wave modulating plate mounted in the loudspeaker cabinet.

DETAILED DESCRIPTION

The characteristics of the present invention consist in th-e unique design of the frame as shown in Fig. 2.

To reduce the interference of reflected negative sound waves with the sound-producing conic body after the speaker has been installed in the cabinet, according to the present invention, the through holes of the conventional speaker frame (Fig. 1) are changed to an open type filter in continuous VV shape in cross section (Fig. 2, 3, 4, 5) of which the closed VV ends are facing the sound-producing conic bodyl while the open VV ends are facing away from the said conic body (Fig. 3), and the said VV shapes are characterized in that the distance a between the 2 base points of any VV shape is greater than the corresponding and opposite open distance b, and the angle 0 of each V shape is less than 90 degrees. The principles on which the present invention functions are as follows:

(1) After a loudspeaker is installed into a cabinet, negative sound wave tend to reflect back into contact with the conic bodyi and the smaller is the inside of the J:

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cabinet, the closer the phase difference between the opposing waveforms approachs 180 degrees; the reflected sound waves not only tend to supress the output, but tend to produce a resonance frequency corresponding to the space inside the cabinet. thus sounds of certain frequencies are emphasized and an inequity of frequency response results; such phenomenon is particularly perceptible in smaller enclosures at lower frequencies. With the " VV shape effect" of the present invention, the reflected sound waves within the cabinet are less likely to repass through the VV holes thus ultimately are absorbed by the walls of the cabinet or the sound absorbing material fixed therein. The small fraction of negative waves that leak back to the conic body area are reduced in amount and delayed in time so that interference with the conic body is minimal, therefore an improved middle and lower frequency response results, exactly those sounds which are most difficult to reproduce accurately in smaller speaker cabinets.

(2) in general, light, thin material in conic shape is used-for the soundproducing body of the loudspeaker. Deformation of the said conic body occurs upon vibration, to a lesser degree when moving forward (away from the magnet) and to a greater degree when moving backward (toward the magnet); according to the present invention, airflow caused by the vibration of the conic body is adjusted by means of the VV shape frame, deformation differences are reduced, and waveform distortion is improved.

The frame of the loudspeaker of the present invention can be structured of any hard material and the plate thereof can be formed into random continuous geometric shapes such as elongated stripes, cones, hives, and the like (Fig. 6r 7p 8). The structure of the loudspeaker cabinet (7) according to the present invention as shown in 1 1 - G - Fig. 9 is comprised mainly of a loudspeaker (1), a wave modulating plate (8), and enclosing cabinet (9) and characterized in that the wave modulating plate which is constructed according to the characteristics of the above mentioned VV configuration also serves to substantially reduce the interference of negative sound waves with the soundproducing conic body, eliminate resonance problems of the speaker cabinet, and improve the efficiency of the loudspeaker system. In addition, such a VV shaped wave modulating plate can be used in a multi-layered manner to further enhance the above mentioned functions, or the plate can be reversely disposed in shapes of /\A for use in other equipment where air must be allowed to flow through so as to reduce leakage of sound. Also, the plate can be formed into the shape ofk). V without being against the above mentioned requirements that a is greater than b and the angle 0 of each V is less than 90 degrees.

Although the present invention has been described in connection with preferred embodiments, it is to be understood that numerous modifications, changes and equivalents can be made by those skilled in the art, all of which fall within the true scope contemplated by the invention.

7

Claims

C L A I M S

1. An improved loudspeaker comprised of a frame, a sound-producing conic body, a yoke, and a permanent magnet, wherein said frame is in open-hole continuous shape- in cross-section with the closed ends of each shape facing the sound-producing conic body and the open ends of each \/\/ shape facing away from the said conic body, the distance a between the two base points of any shape is greater than the corresponding and opposite open distance b, and the included angle 9 of each \/ shape is less than 90 degrees.

2. A loudspeaker according to claim 1, wherein the frame of said \/\/ configurations is in a multi-layered fashion.

3. A loudspeaker according to claim 1 or 2, wherein the open-holes of the frame are in extended continuous geometric shapes in plane section.

4. An improved wave modulating plate of continuous \/\/ shape in crosssection, wherein the distance a between the two base points of any \/\/ shape is greater than the corresponding and opposite open distance b, and the included angle 9 of each \/ shape is less than 90 degrees.

5. An improved wave modulating plate according to claim 4, wherein the plate of \/\/ configuration is in a multi-layered fashion.

6. An improved wave modulating plate according to claim 4 or 5, when utilized in any sound system where air or sound is to be controlled.

7. An improved wave modulating plate according to claim 4, 5 or 6. wherein the holes of the plate are in extended continuous geometric shapes in plane section.

8. A loudspeaker cabinet arrangement comprising a loudspeaker, an enclosing cabinet, and a wave modulating plate, wherein the frame of the loudspeaker is of continuous shape in cross-section and the wave modulating plate is also of continuous \/\/ shape in cross-section.

9. A loudspeaker cabinet arrangement according to claim 8, wherein the wave modulating plate is in a multi-layergd fashion.

10. A loudspeaker arrangement substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

8 Published 1989 atThe Patent Office, State House, 66171 High Holborn, LondonWClR 4TP. Further copies maybe obtained from The Patent Oftice. Sales Branch, St Mary Cray, Orpington, Kent BF.5 3RD. Printed by Multiplex techniques ltd, St Mary Cray. Kent, Con- 1/87 f

10. A loudspeaker substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

11. A wave modulating plate substantially as hereinbefore described with reference tot and as illustrated in, the accompanying drawings.

12. A loudspeaker arrangement substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

I' n 1 ' J % Amendments to the claims have been filed as follows a C L A I M S 1. An improved wave modulating plate of continuous \/V shape in crosssection, wherein the distance a between the two base points of any \/\/ shape is greater than the corresponding and opposite open distance b, and the inc-luded angle G of each \/ shape is less than 90 degrees.

2. An improved wave modulating plate according to claim 1, wherein the plate of \/\/ configuration is in a multi-layered fashion.

3. An improved wave modulating plate according to claim 1 or 2, when utilized in any sound system where air or sound is to be contr61led.

4. An improved wave modulating plate according to any one of claims 1 to 3, wherein the holes of the plate are in extended continuous geometric shapes in plane section.

5. An improved 'loudspeaker comprised of a frame, a sound-producing conic body, a yoke, and a permanent magnet, wherein said frame includes a wave modulating plate according to any one of claims 1 to 4, and is in openhole continuous \/\/ shape in cross-section with the closed ends of each \/\/ shape facing the sound-producing conic body and the open ends of each \/\/ shape facing away from the said conic body.

6. A loudspeaker according to claim 5, wherein the open-holes of the frame are in extended continuous geometric shapes in plane section.

7. A loudspeaker cabinet arrangement comprising a loudspeaker, an enclosing cabinet, and a wave modulating plate. wherein the frame of the loudspeaker is of continuous \/\/ shape in cross-section and the wave modulating plate is according to any one of claims 1 to 4.

C t it a 8. A loudspeaker substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.

9. A wave modulating plate substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.