WO1994004008A1

WO1994004008A1 - Sonic wave generator

Info

Publication number: WO1994004008A1
Application number: PCT/US1992/006754
Authority: WO
Inventors: Daniel T. Wolf
Original assignee: Wolf Daniel T
Priority date: 1990-04-27
Filing date: 1992-08-07
Publication date: 1994-02-17

Abstract

A sonic wave generator (10) includes at least one pair of concave acoustic baffles (12, 14, 16) arranged in concavely facing relationship in mutual coaxial alignment. The facing acoustic baffles (18, 20, 22) of the pair (12, 14, 16) are spaced apart from each other by a predetermined distance so that an annular opening (30) is formed between the peripheral edges of the openings of the facing concave baffles (18, 20, 22). A driven diaphragm (32) is located at the closed end (26) of each audio baffle (18, 20, 22) opposite the open end (24) of the baffle (18, 20, 22). The driven diaphragms (32) located in the baffle pair (12, 14, 16) face toward each other in mutual coaxial alignment and in coaxial alignment with the acoustic baffles (18, 20, 22). Each concave baffle (18, 20, 22, 122, 222) of respective baffle pairs (12, 14, 16, 116, 216) may be generally cylindrical (122), hemispherical (222), or parabolic (18, 20, 22), for example.

Description

TITLE: SONIC WAVE GENERATOR

TECHNICAL FIELD The present invention relates to the field of sonic wave generators and more particularly to a sonic wave generator which accurately reproduces an incoming signal as a sound and which projects the sound uniformly over an area 360 degrees centered on the speaker system.

BACKGROUND ART Over the years there have been many attempts to design sonic wave generators with improved sound reproduction fidelity.

The following U.S. Patents are representative of these attempts. U.S. Patent No. 1,642,124 issued on September 13, 1927 to F. E. Miller et al U.S. Patent No. 1,696,305 issued on December 25, 1928 to M. R. Hutchison; U.S. Patent No. 1,677,605 issued on July 17, 1928 to S. Strobino; U.S. Patent No. 1,734,377 issued on November 5, 1929 to J. B. Hawley; U.S. Patent No. 1,787,946 issued on January 6, 1931 to W. D. LaRue;

U.S. Patent No. 1,819,183 issued on August 18, 1931 to

1. Ludlow; U.S. Patent No. 2,297,972 issued on October 6, 1942 to B. E. Mills; U.S. Patent No. 2,832,843 issued on April 29, 1958 to B. F. Miessner; U.S. Patent No. 2,989,597 issued on June 20, 1961 to J. A.

Victoreen; U.S. Patent No. 3,015,366 issued on January

2, 1962 to G. M. Bishop; U.S. Patent No. 3,022,377 issued on February 20, 1962 to L. J. Bobb et al; U.S. Patent No. 3,202,773 issued on August 24, 1965 to B. W. Tichy; U.S. Patent No. 3,371,742 issued on March 5,

1968 to D. H. Norton et al; U.S. Patent No. 3,477,540 issued on November 11, 1969 to A. Rizo-Patron R. ; U.S. Patent No. 3,512,606 issued on May 19, 1970 to S. C. Anastin; U.S. Patent No. 4,016,953 issued on April 12, 1977 to R. J. Butler; U.S. Patent No. 4,039,044 issued on August 2, 1977 to O. Heil; and U.S. Patent No. 4,107,479 issued on August 15, 1978 to O. Heil. Of the above-listed patents, U.S. Patent No. 1,696,305; U.S. Patent No. 1,819,183; U.S. Patent No. 2,297,972; U.S. Patent No. 2,832,843; U.S. Patent No. 3,477,540; and U.S. Patent No. 4,016,953 show two speakers in facing relationship and U.S. Patent No. 1,734,377 and U.S. Patent No. 3,477,540 show two speakers in facing, spaced apart relationship. U.S. Patent No. 3,015,366 shows sound propagating mechanisms located in coaxial sequential series by size. These prior art audio systems have various drawbacks which adversely effect the accuracy of sound reproduction and the sound projection.

DISCLOSURE OF INVENTION The present invention recognizes the drawbacks of the prior art systems and provides a straightforward sonic wave generator which obviates these drawbacks.

More particularly, the present invention provides in one embodiment, a sonic wave generator comprising at least one pair of concave acoustic baffles concavely facing each other in mutual coaxial alignment and spaced apart from each other a predetermined distance whereby the peripheral edges of the opening of the concave baffles cooperate to define an annular opening therebetween, and a driven diaphragm located at the closed end of each acoustic baffle opposite the open end of the baffle, the driven diaphragms facing each other in mutual coaxial alignment and in coaxial alignment with the acoustic baffles.

In another embodiment, the present invention provides a sonic wave generator comprising a plurality of pairs of concave acoustic baffles, the two acoustic baffles of each baffle pair concavely face each other in mutual coaxial alignment and are spaced apart from each other a predetermined distance whereby the peripheral edges of the opening of the concave baffles cooperate to define an annular opening therebetween; each pair of acoustic baffles being of a different size than the other pairs of acoustic baffles, a pair of driven diaphragms associated with each pair of acoustic baffles, a driven diaphragm located at the closed end of each acoustic baffle; the pair of driven diaphragms associated with each acoustic baffle pair face toward each other in mutual coaxial alignment and in coaxial alignment with the acoustic baffle pair in which the driven diaphragm pair is located; and each pair of driven diaphragms being sized to operate over a different frequency range than the other pairs of driven diaphragms.

BRIEF DESCRIPTION OF DRAWINGS A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings wherein:

FIGURE 1 is a side view of an a sonic wave generator embodying the present invention with portions broken away to show internal details;

FIGURE 2 is a side view of one embodiment of a component of the sonic wave generator of Figure 1; and

FIGURE 3 is a side view of another embodiment of a component of the sonic wave generator of Figure 1. MODES FOR CARRYING OUT THE INVENTION AND

INDUSTRIAL APPLICABILITY With reference to the drawing, there is shown a sonic wave generator, generally denoted as the numeral 10, of the present invention. The sonic wave generator 10 has a plurality of pairs 12, 14 and 16 of acoustic baffles 18, 20 and 22, respectively. As shown, the sonic wave generator 10 has three pairs of acoustic baffles. One acoustic baffle pair 16 is for a low audio frequency range, another acoustic baffle pair 14 is for a mid-range audio frequency range, and yet another baffle pair 12 is for a high audio frequency range. The physical size of the acoustic baffles 22 of the low audio frequency pair 16 are larger than the baffles 20 of the mid-range frequency pair 14, and the baffles 20 are larger than the baffles 18 of the high audio frequency range pair 12. Preferably, the ratio of the physical size of the baffles 22 to the baffles

20 is the same as the ratio of the physical size of the baffles 20 to the baffles 18. For example, if the baffle 20 is .66 the size of the baffle 22, then the baffle 18 is .66 the size of the baffle 20. The baffles 18, 20 and 22, and the baffle pairs 12, 14 and 16 are essentially identical except for size, as discussed hereinbefore. Therefore, for the sake of brevity and clearness of understanding, only the baffle pair 16 and the acoustic baffles 22 forming the baffle pair 16 will be described, it being understood that the description applies equally to the other baffle pairs 12 and 14, and the acoustic baffles 18 and 20.

The acoustic baffles 22 are concave in shape having an open end 24 and a closed end 26 opposite the open end 24. The acoustic baffles 22 of the baffle pair 16 concavely face each other in mutual coaxial alignment. The acoustic baffles 22 are spaced apart from each other along the coaxis of alignment a predetermined distance whereby the peripheral edges 28 of the open end 24 of the baffles 22 cooperate to define an annular opening generally denoted by the number 30, therebetween. Preferably, the area of the annular opening 30 is somewhat less than the area of the driven diaphragms 32. This sizing of the annular opening 30 increases the velocity of the air as it exits through the annular opening 30 providing a slight back pressure in the baffles 22 which tends to shunt harmonic resonance. A driven diaphragm 32 is located at the closed end of each acoustic baffle 22 opposite the open end 4 of the acoustic baffle 22. The driven diaphragms 32 face each other in mutual coaxial alignment, and also in coaxial alignment with the acoustic baffle 22 of the baffle pair 16. The driven diaphragms 32 are of equal diameter, and the distance from each driven diaphragm to the centerline of the annular opening 30, measured along the axis of alignment, is twice the driven diaphragm diameter. This relationship provides a half wave air column between the two driven diaphragms 32 with a sound radiating zone at the geometric center of the baffle pair 16.

With continued reference to Figure 1, the acoustic baffle 22 is parabolic in shape. The walls of the acoustic baffle are preferably fabricated of a sound reflecting material such as, for example, aluminum or brass. Furthermore, the walls of the acoustic baffle 22 are preferably homogenous without any discontinuities or seams. Toward this objective, the acoustic baffle 22 can be fabricated by a spinning process. With reference to Figure 2, there is shown one embodiment of an acoustic baffle 122 of a baffle pair 116 which is generally cylindrical in shape having one open end 124 and an opposite closed end 126.

Figure 3 shows another embodiment of an acoustic baffle 222 of a baffle pair 216 which is hemispherical in shape having an open end 224 and an opposite closed end 226.

With references once again to Figure 1, the sonic wave generator 10 also includes a support structure 34. As shown, the support structure 34 is formed of a plurality of elongated side beams 36 interconnected at their top ends by top braces 38 and interconnected at their bottom ends by bottom braces 40. The details of the support structure 34 are incidental. The main criteria of the support structure 34 is that it be open so as not to interfere with sound transmission. The baffle pairs 12, 14 and 16 are mounted in the support structure in mutual coaxial alignment with the coaxis of alignment being vertically oriented.

The acoustic baffles 20, 22 and 24 of the baffle pairs 12, 14 and 16, respectively are attached individually of each other to the support structure by attachment means, generally denoted as the numeral 42. The attachment means 42 comprises resilient means 44 such as two coil springs arranged in longitudinal alignment with dampening means 46, such as a section of rigid plastic material, located between and interconnecting the two coil springs. The free end of one coil spring is connected to the support structure 34 and the free end of the other coil spring is attached to the acoustic baffles. Thus, each audio baffle is individually resiliently supported in the support structure 34.

With continued reference to Figure 1, each pair 12, 14 and 16 of acoustic baffles 18, 20 and 22 is of a different size than the other baffle pairs and are sequentially arranged according to baffle size. In addition, each pair of driven diaphragms 24 associated with each baffle pair 12, 14 and 16 is sized to operate over a different frequency range than the other pairs of driven diaphragms. For example, the pair of driven diaphragms 24 associated with the baffle pair 16 are sized to operate in a low frequency range of, for example, 20-500 Hertz, the pair of driven diaphragms 24 associated with the baffle pair 14 are sized to operate in a mid-frequency range of, for example, 500-2000 Hertz, and the pair of driven diaphragms 24 associated with the baffle pair 12 are sized to operate in a high frequency range of, for example, 2000-6000 Hertz. It is also contemplated that the different frequency ranges which the different pairs of driven diaphragms operate overlap. For example, the pair of driven diaphragms 24 of the baffle pair 16 could operate in a low frequency range of 20-500 Hertz; the pair of driven diaphragms 24 of baffle pair 14 could operate in a mid frequency range of 450-2000 Hertz; and the pair of driven diaphragms 24 of the baffle pair 12 could operate in a high frequency range of 1950-6000 Hertz. It is contemplated that the driven diaphragms 24 of each driven diaphragm pair be operatively connected in series so as to operate in phase with each other, and alternatively that the driven diaphragms 24 of each driven diaphragm pair be operatively connected in parallel so as to operate out of phase with each other. The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations should be understood therefrom for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention or scope of the appended claims.

Claims

CLAIMS :

1. A sonic wave generator (10) comprising: at least one pair of concave acoustic baffles

(116) , each concave acoustic baffle (122) being generally cylindrical in shape and formed with an open end (124) defined by a peripheral edge and a closed end (126) opposite the open end (124) concavely facing each other in mutual coaxial alignment and spaced apart from each other a predetermined distance whereby the peripheral edge of the open ends (124) of the concave baffles (122) cooperate to define an annular opening (30) therebetween; and, a driven diaphragm (32) located at the closed end (126) of each acoustic baffle (122) opposite the open end (124) of the baffle (122), the driven diaphragms

(32) facing each other in mutual coaxial alignment and in coaxial alignment with the coaxial baffles (122) .

2. A sonic wave generator (10) comprisj.ng: at least one pair of concave acoustic baffles (216) , each concave acoustic baffle (222) being generally hemispherically shaped, and formed with an open end (224) defined by a peripheral edge and a closed end (226) opposite the open end (224) concavely facing each other in mutual coaxial alignment and spaced apart from each other a predetermined distance whereby the peripheral edge of the open ends (224) of the concave baffles (222) cooperate to define an annular opening (30) therebetween; and a driven diaphragm (32) located at the closed end (226) of each acoustic baffle (222) opposite the open end (224) of the baffle (222) , the driven diaphragms (32) facing each other in mutual coaxial alignment and in coaxial alignment with the coaxial baffles (222) .

3. A sonic wave generator (10) comprising: at least one pair of concave acoustic baffles (12, 14, 16), each concave acoustic baffle (18, 20, 22) being generally parabolic, and formed with an open end (24) defined by a peripheral edge and a closed end (26) opposite the open end (24) concavely facing each other in mutual coaxial alignment and spaced apart from each other a predetermined distance whereby the peripheral edge of the open ends (24) of the concave baffles (18, 20, 22) cooperate to define an annular opening (30) therebetween; and, a driven diaphragm (32) located at the closed end (26) of each acoustic baffle (18, 20, 22) opposite the open end (24) of the baffle (18, 20, 22), the driven diaphragms (32) facing each other in mutual coaxial alignment and in coaxial alignment with the coaxial baffles (18, 20, 22).

4. A sonic wave generator (10) comprising: a plurality of pairs of concave acoustic baffles (12, 14, 16), each baffle (18, 20, 22) formed with an open end (24) defined by a peripheral edge and a closed end (26) opposite the open end (24) , the acoustic baffles (18, 20, 22) of each baffle pair (12, 14, 16) concavely face each other in mutual coaxial alignment and are spaced apart from each other a predetermined distance whereby the peripheral edges of the open ends (24) of the concave baffles (18, 20, 22) cooperate to define an annular opening (30) therebetween; each pair of acoustic baffles (12, 14, 16) being of a different size than the other pairs of acoustic baffles (12, 14, 16); a pair of driven diaphragms (32) associated with each pair of acoustic baffles (12, 14, 16), a driven diaphragm (32) located at the closed end (26) of each acoustic baffle (18, 20, 22), the pair of driven diaphragms (32) associated with each acoustic baffle pair (12, 14, 16) face each other in mutual coaxial alignment and in coaxial alignment with the acoustic baffle pair (12, 14, 16) in which the driven diaphragm (32) is located; and, each pair of driven diaphragms (32) being sized to operate over a different frequency range than the other pairs of driven diaphragms (32) .

5. The sonic wave generator (10) of Claim 4, wherein the different frequency ranges at which the different pairs of driven diaphragms (32) operate overlap.

6. The sonic wave generator (10) of Claim 4, wherein the plurality of pairs of acoustic baffles (12, 14, 16) are in mutual coaxial alignment.

7. The sonic wave generator (10) of Claim 6, wherein the plurality of pairs of acoustic baffles (12, 14, 16) are sequentially arranged according to baffle (18, 20, 22) size.

8. The sonic wave generator (10) of Claims 1, 2, 3, or 4 wherein: the driven diaphragms (32) are of equal diameter; and the distance between each of the driven diaphragms (32) to the centerline of the annular opening (30) measured along the coaxis of alignment is twice the driven diaphragm (32) diameter.

9. The sonic wave generator (10) of Claims 1, 2, 3, or 4 wherein the coaxis of alignment is vertical.

10. The sonic wave generator (10) of Claims 1, 2, 3, or 4 further comprising: a support structure (34) ; and means (42) for attaching the acoustic baffles to the support structure (34) .

11. The sonic wave generator (10) of Claim 10, wherein the acoustic baffle attachment means (42) comprises resilient means (44) for resiliently supporting the acoustic baffles (18, 20, 22) to the support structure (34) .

12. The sonic wave generator (10) of Claim 11, wherein the acoustic baffle attachment means (42) comprises dampening means (46) for dampening the motion of the resilient means (44) .

13. The sonic wave generator (10) of Claim 10, wherein the acoustic baffle attachment means (42) attaches the acoustic baffles (18, 20, 22) individually of each other to the support structure (34) .

14. The sonic wave generator (10) of Claims 1, 2, 3, or 4 wherein the driven diaphragms (32) are operatively connected so as to operate in phase with each other.

15. The sonic wave generator (10) of Claims 1, 2, 3, or 4 wherein the driven diaphragms (32) are operatively connected so as to operate out of phase with each other.