초록 ▼

An electro-acoustic transducer using thin, lightweight, planar diaphragms driven by strategically located, coil-driven, high-energy, permanent magnets. A framework maintains the diaphragms in substantially co-planar relationship a predetermined distance from and parallel to a rear support wall. The

An electro-acoustic transducer using thin, lightweight, planar diaphragms driven by strategically located, coil-driven, high-energy, permanent magnets. A framework maintains the diaphragms in substantially co-planar relationship a predetermined distance from and parallel to a rear support wall. The diaphragms include at least one hinged woofer diaphragm and a foam-supported tweeter diaphragm. The small, high energy movable permanent magnets are attached to the rear surface of each movable diaphragm. Cooperating with each movable magnet is a respective, stationary electromagnetic coil with a crossover network directing the incoming signal to the appropriate coils, thereby placing the magnets and attached diaphragms into cooperating fore and aft motion. The frontal acoustical waves produced by each woofer constructively interfere to augment low frequency response. The tweeter construction provides wide frontal dispersion of high frequency acoustical waves. Woofer backwaves are attenuated before emerging along the rear support wall and the tweeter backwave is vented into a rear isolative chamber.

대표청구항 ▼

1. An electro acoustic planar transducer comprising: a. a substantially planar frame having a front side and a rear side; b. means for mounting said frame on a vertical planar surface so that said front side faces away from the planar surface; c. a planar, rectangular, woofer diaphragm, the lon

1. An electro acoustic planar transducer comprising: a. a substantially planar frame having a front side and a rear side; b. means for mounting said frame on a vertical planar surface so that said front side faces away from the planar surface; c. a planar, rectangular, woofer diaphragm, the long dimension of said woofer diaphragm being in vertical attitude, said woofer diaphragm having a vertical proximal edge and an opposite vertical distal edge; d. means for mounting said woofer diaphragm on and parallel to said frame for alternating movement toward and away from said front side and said rear side, said proximal edge being mounted on said frame and said distal edge being movable; e. first cooperating coil and magnet means, interposed between said frame and said woofer diaphragm, for driving said woofer diaphragm in response to an electrical signal impressed upon said first coil means, said distal edge partaking in excursions as said woofer diaphragm is driven; f. sound absorptive means mounted on said frame and interposed between at least one predetermined portion of said woofer diaphragm and said planar surface for attenuating the acoustic back waves generated by said predetermined portion of said woofer diaphragm; g. a planar tweeter diaphragm; h. means for mounting said tweeter diaphragm on and parallel to said frame for alternating movement toward and away from said front side and said rear side; and, i. second cooperating coil and magnet means interposed between said frame and said tweeter diaphragm for driving said tweeter diaphragm in response to said electrical signal impressed upon said second coil means. 2. A transducer as in claim 1 in which said predetermined portion of said woofer is located in the vicinity of said opposite, vertical distal edge where maximum excursions occur. 3. A transducer as in claim 2 further including an elongated highly compliant foam cushion interposed between and mounted vertically on said frame and said woofer diaphragm intermediate said vertical edges thereof. 4. A transducer as in claim 3 further including a vertical highly compliant foam strip interposed between and mounted on said planar tweeter diaphragm and said frame. 5. A transducer as in claim 4 in which said frame comprises a vertically elongated "picture frame" including horizontal top and bottom rails and a pair of vertical sidepieces; a pair of parallel vertical ribs extending between said top and bottom rails; a rigid front plate mounted on the front surface of said ribs; a rigid rear plate spanning said ribs parallel to and spaced from said front plate to define with said front plate and said ribs an acoustic chamber; and a perforate cage enclosing said sound absorptive means, said cage being spaced from the adjacent wall to form an acoustic aperture therebetween. 6. A transducer as in claim 5 including a pair of parallel vertical slats mounted on the front surface of said front plate, said one vertical edge of each of said planar woofer diaphragms being mounted on the respective one of said slats. 7. A transducer as in claim 6 further including a highly compliant foam surround mounted on said frame and encompassing the peripheral margin of said woofer and said tweeter diaphragms combined. 8. An electro-acoustical transducer for use on a planar surface comprising: a. A pair of lightweight, substantially rigid, planar, woofer diaphragms; b. lightweight substantially rigid, planar, tweeter diaphragm; c. a frame having a front side and a rear side, said rear side facing toward the planar surface; d. means for mounting said woofer diaphragms and said tweeter diaphragm on said frame in co-planar relation a predetermined distance from the planar surface of predetermined width to form a channel around the periphery of said diaphragms, said woofer diaphragms being attached to said frame at their adjacent proximal edges allowing unimpeded front and rear motion of their respective distal edges; and, e. electro-mechanical drive means mounted on said frame and interconnected to said woofer diaphragms a predetermined distance from said adjacent proximal edges of said woofer diaphragms for placing said woofer diaphragms into front and rear motion about their respective proximal edges in response to an electrical drive signal, said drive means being further interconnected to said tweeter diaphragm for placing said tweeter diaphragm into front and rear motion in accordance with a supplied electrical drive signal. 9. A transducer as in claim 8 including a pair of pieces of highly compliant material interposed between and attached to said frame and said woofer diaphragms and a piece of highly compliant material interposed between and attached to said frame and said tweeter diaphragm, said material being yieldable to permit fore and aft motion of said diaphragms relative to said frame. 10. A transducer as in claim 8 in which said peripheral channel underlies the distal edge portion of each of said woofer diaphragms and acoustically vents the backwaves generated thereby in a lateral direction, the intent of said predetermined channel width being selected so that the laterally vented backwave and the frontal wave generated by said woofer diaphragm advance in substantially perfect phase relationship. 11. A transducer as in claim 10 including an acoustically absorptive cell mounted on said frame and interposed between said distal edge portion of each of said woofer diaphragms and the underlying portion of said peripheral channel to reduce the amplitude of the backwave generated by said woofer diaphragm. 12. A transducer as in claim 11 in which said cell includes layers of DACRON and FIBERGLASS, and a perforated cage encompassing the after side of said cell.