Omniphonic microphone and loudspeaker system

Abstract: The invention comprises a microphone and loud speaker system in which the components include a cylinder (26) having a centre section and an end section (26A, 26B) at each end of the centre section and an axial alignment with one another. The adjacent ends of the centre and end sec­ tions (26A, 26B) are truncated at an angle of 35° 16′ and the long­ itudinal axis of the planes of the ellipses thus formed are rotated through 45°. These planes are substantially isomorphic to the tympanic membrane of the human hearing structure and represent half the dihedral angle of a regular tetrahedron. All of the loudspeaker transducers are shielded by opiculae which are cylindrical structures (37) also truncated at one end at half the dihedral angle of a regular tetrahedron, namely, 35° 16′ , and have the planes thereof rotated 45° to the horizontal.

Description: This invention relates to new and useful improvements to omniphonic microphone and loud speaker systems illustrated and described in my U.S. Patent 4122910 (& FR-A-2345046). In this U.S. Patent, a regular tetrahedron construction is used for both the microphone and loud speaker components. However, that particular construction contains some directional ambiguity, which ambiguity is significantly reduced by the improvements described hereafter. According to one aspect of the present invention there is provided a microphone system comprising a substantially cylindrical module with a longitudinal axis and comprising a centre section with two elliptical outer end faces truncated at one half of the dihedral angle of a regular tetrahedron and two end sections at opposite ends of the centre section in longitudinal alignment therewith, each end section having an elliptical inner end face confronting a respective one of the outer end face of the centre section, each said inner end face and the outer end face confronted thereby lying in substantially parallel, spaced planes, and each elliptical end face of the centre section and the end sections having a long axis oriented at approximately 45° to a horizontal plane, and a microphone transducer situated centrally in each of said outer end faces of said centre section and said inner end faces of each of said end sections. According to another aspect of the present invention there is provided a loudspeaker system comprising a substantially cylindrical module comprising a centre section with two elliptical outer end faces truncated at one-half the dihedral angle of a regular tetrahedron and two end sections of opposite ends of the centre section in longitudinal alignment therewith, each end section having an elliptical inner end face confronting a respective one of the outer end faces of the centre section, each said inner end face and the outer end face confronted thereby lying in substantially parallel, spaced planes, and each elliptical end face of the centre section and the end sections having a long axis oriented at approximately 45° to a horizontal plane, and a speaker transducer situated within and spaced in from each outer end of said centre section and facing outwardly therefrom and a further transducer situated within and spaced outwardly from the inner ends of each said end sections. According to another aspect of the present invention there is provided an optimal shadow omniphonic microphone and loudspeaker system comprising in combination an omniphonic microphone component, a speaker component and electronic means coupling the microphone and speaker components for processing signals from the microphone component and transmitting signals to the speaker component, each of said microphone and loudspeaker components including a substantially cylindrical module with a longitudinal axis and comprising a centre section with two elliptical outer end faces truncated at approximately one half the dihedral angle of a regular tetrahedron and two end sections at opposite ends of the centre section in longitudinal alignment therewith, each end section having an elliptical inner end face confronting a respective one of the outer end faces of the centre section, each said inner end face and the outer end face confronted thereby lying in a substantially parallel, spaced planes, and each elliptical end face of the centre section and the end sections having a long axis oriented at approximately 45° to a horizontal plane, a microphone transducer situated centrally in each of said outer end faces of said centre section of said microphone component and said inner end faces of each of said end sections of said microphone component, and a speaker transducer situated in and spaced in from each of said outer end faces of said centre section of said speaker component and a further speaker transducer situated In and spaced outwardly from the inner end faces of each of said end sections. According to a further aspect of the present invention there is provided an operculum acting as a baffle means for use with a loudspeaker component and comprising a truncated cylinder secured adjacent a loudspeaker transducer with an inner end being operatively situated to said transducer, and an outer end being truncated at approximately one half the dihedral angle of a regular tetrahedron, the long axes of the ellipses formed by said truncation being oriented at approximately 45° to the horizontal. The improvements include the following technical features: (1) All of the transducers are shielded by operculae which are cylindrical structures truncated at 1/2 dihedral angle of the regular tetrahedron, namely, 35° 16' and where planes are set at 45° to the horizontal. (2) The planes of the elliptical openings of the operculae correspond or are isomorphic to the tympanic membrane of the human hearing structure. (3) The operculae of the optimal shadow omniphonic microphone component and of the isomorphic module/operculated baffles are isomorphic to the truncated cylinders described in the microphone and loud speaker components of U.S. Patent 4122910 and indicated in that patent by reference character 23. (4) The planes of the truncated openings of the optimal shadow omniphonic microphone components correspond to the dihedral planes of the omniphonic microphone of the above U.S. Patent and illustrated in Figure 8 thereof. (5) The planes of the truncated openings of the isomorphic module of the loud speaker component correspond to the dihedral planes of the omniphonic loud speaker illustrated in Figure 9 of the above U.S. Patent. (6) The planes of all of the baffle operculae are set at 45° and incline downwardly and away from the listener. DESCRIPTION OF THE DRAWINGS Figure 1 is similar to Figure 8 of U.S. Patent #4122910 and shows schematically the location of the optimal shadow omniphonic microphone component of the present invention. Figure 2 is an enlarged rear elevational view of this microphone component with electronic connections being shown schematically. Figure 3 is a front elevation of Figure 2. Figure 4 is a schematic end elevation of one of the inner ends of the truncated cylinder carrying the microphones. Figure 5 is a view similar to Figure 2 showing the tetrahedron loud speaker structure of U.S. Patent 4122910 and illustrating, schematically, the core of the tetrahedron utilized in the loud speaker module of the present invention. Figure 6 is a schematic view of the relationship of the isomorphic module and the outer speaker components. Figure 7 is a frontal elevation of Figure 6 with the electronic connections shown schematically. Figure 8 is an enlarged frontal elevational view of the isomorphic module of Figure 7. Figure 9 is an enlarged isometric view of one of the operculae. Figure 10 is a partially schematic front elevation of the left and right baffles of the lefthand speaker component. Figure 11 is a view similar to Figure 10 but showing the left and right baffles of the righthand speaker component. Figure 12 is a fragmentary cross-sectional schematic view of part of one of the outer speaker cabinets showing the relationship between the operculae and the transducers. In the drawings like characters of reference indicate corresponding parts in the different figures. DETAILED DESCRIPTION Proceeding to describe the invention in detail, reference should first be made to Figures 1 through 4 which which illustrate the Optimal Shadow Omniphonic Microphone portion of the invention. Figure 1 shows partially schematically, the tetrahedron 20 forming the microphone module illustrated and described in U.S. Patent 4122910 and specifically Figure 8 thereof. Reference character 21 illustrates the centre of this tetrahedral structure and points 22 and 23 show the theoretical locations of the centre of the microphones illustrated in Figure 8 of this U.S. patent. The cylindrical outline 24 shown in phantom in Figure 1, illustrates a core from this tetrahedron, the portions of which form the microphone component collectively designated 25 illustrated in Figures 2, 3 and 4 of the enclosed drawings. This component 25 consists of a central portion 26, a righthand portion 27 and a lefthand portion 28, it being understood that Figure 2 is a rear view of the component whereas Figure 3 is front elevational view. The aforementioned theoretical centre of the tetrahedron of Figure 1 is also illustrated by reference character 21 of Figure 2 so that this component retains the regular tetrahedral form of the omniphonic microphone of the U.S. patent, as an abstraction. The cylindrical construction is formed from a solid material and the ends 26A and 26B of the central section are truncated at an angle of 35° 16' which equals half the dihedral angle of the regular tetrahedron shown in Figure 1. The corresponding inner ends 27A and 28A of the end portions 27 and 28 are also truncated at a similar angle of 35° 16' and the longitudinal axes of the ellipsis formed by the truncation is rotated through 45°. This is illustrated by comparison of Figures 2 and 3 and shown schematically in Figure 4. Conventional microphone elements 29 open onto these truncated faces of all four ends and are connected electronically to a conventional microphone mixer 30 and thence to left and right amplifiers all of which is conventional. The truncated ends 26B/27A and 26A/28A are spaced apart from one another thus forming an adjustable gap therebetween which may be in the order of between 1 - 4 mm as an example and this gap is selected for optimum sound reception with minimal ambiguity. Figures 5 through 12 show the isomorphic module/operculated baffle assemblies constituting the loudspeaker component of the system and reference should first be made to Figure 5 which shows a regular tetrahedron 31 similar to the loudspeaker tetrahedron shown in Figure 9 of U.S. Patent 4122910. In this U.S. patent, the transducers 32 are situated on adjacent faces 33 of the tetrahedron and the cylinder 34 shown in phantom in Figure 5 of the present application constitutes theoretically, the isomorphic module collectively designated 35 with reference character 36 indicating the theoretical centre of the tetrahedron and of the cylinder 35. The construction shown in detail in Figure 8, is similar to the module of the microphone component shown in Figure 3 in that it contains a central section 37 and end sections 38 and 39. These are formed from hollow cylindrical material filled with acoustical insulation material (not illustrated). The outer ends 37A and 37B of the centre section 37 are also truncated at an angle of 35° 16' (half the dihedral angle of the regular tetrahedron) as are the inner ends 38A and 39A. Once again the longitudinal axis of the ellipse formed by this truncation of all of these ends is rotated through 45° as clearly shown by a consideration of Figure 8 and comparing same with the structure shown in Figures 2 and 3. Mid-range transducers 40 are mounted spaced inwardly from the ends 37A/38A and inwardly from the ends 37B and 39A and are connected electronically to the amplifier 41 as shown. Once again the truncated ends of the sections 37, 38 and 39 are spaced apart and the gap therebetween may be adjusted similar to that described for the microphone components. Figure 6 shows, schematically, the alignment of all of the transducers not only of the isomorphic module but also of outer or side speaker components collectively designated 42 and 43 with the left and right channel connections controlled by amplitude controls 44 and connected to the amplifier as shown. From this schematic view, it will be seen that the outer speakers 42A and 43A are low-range speakers connected to opposite channels and that the inner speakers 42B and 43B are high-range speakers connected to the opposite channels with the crossover being approximately 700 Hz. The four central speakers 40 are mid-range tweeter type speakers and are also connected to the respective channels as illustrated. The cross-over frequency need not be rigidly fixed but may be in a range between 700 - 1500 Hz. The speaker components 42 and 43 may be enclosed in an acoustic suspension or acoustic reflex speaker cabinet 44A of conventional construction with the exception of the speaker baffle panels shown in Figures 10 and 11. Figure 10 shows the left outer baffle panel 45 of the component 42 and the left inner baffle panel 46 also of component 42. Figure 11 shows the right outer baffle panel 47 and the right inner baffle panel 48 both of the speaker component 43. All of the baffle panels include, adjacent the upper end thereof, a plurality of operculated baffles collectively designated 49 adjacent the front of the cones of the speakers 42A and 42B and 43A and 43B respectively. These operculated baffles take the form of small cylindrical components having truncated outer ends 50 formed at half the dihedral angle of a regular tetrahedron, namely, 35° 16'. They are preferably provided with a felt outer cover 51 and a felt inner liner 52 and they are mounted in the baffle panels in a symmetrical array as illustrated. Of importance is the fact that the operculated baffles of the outer panels 45 and 47 are positioned so that the elliptical openings on the outer face of the panels open downwardly and outwardly from the panel whereas the elliptical openings of the inner baffles 46 and 48 open downwardly and inwardly from the baffles as illustrated in Figures 10, 11 and 12. All of the surfaces of the optimal shadow microphone/and the isomorphic module are preferably provided with a felt covering.

Claims: A microphone system comprising a substantially cylindrical module (25) with a longitudinal axis and comprising a centre section (26) with two elliptical outer end faces (26A,26B) truncated at one half the dihedral angle of a regular tetrahedron and two end sections (27,28) at opposite ends of the centre section (26), in longitudinal alignment therewith, each end section having an elliptical inner end face confronting a respective one of the outer end face of the centre section, each said inner end face (27A; 28A) and the outer end face (26A;26B) confronted thereby lying in substantially parallel, spaced planes, and each elliptical end face (26A, 26B, 27A, 28A) of the centre section and the end sections having a long axis oriented at approximately 45° to a horizontal plane, and a microphone transducer (29) situated centrally in each of said outer end faces of said centre section and said inner end faces (27A, 28A) of each of said end sections (27,28). A microphone system according to Claim 1 in which the gap between said inner end faces (27A, 28A) of said outer sections (27,28) and said outer end faces (26A, 26B) of said centre section (26) is adjustable between 1 mm and 4 mm. A loudspeaker system comprising a substantially cylindrical module (35) comprising a centre section (37) with two elliptical outer end faces (37A,37B) truncated at one half the dihedral angle of a regular tetrahedron and two end sections (38,39) at opposite ends of the centre section in longitudinal alignment therewith, each end section (38,39) having an elliptical inner end face (38D;39D) confronting a respective one of the outer end faces (37A;37B) of the centre section (37), each said inner end face (38A;39A) and the outer end face (37A; 37B) confronted thereby lying in substantially parallel, spaced planes, and each elliptical end face (37A;37B;38A;39A) of the centre section (37) and the end sections (38,39) having a long axis oriented at approximately 45° to a horizontal plane, and a speaker transducer (40) situated within and spaced in from each outer end (37A;37B) of said centre section (37) and facing outwardly therefrom and a further transducer (40) situated within and spaced outwardly from the inner ends (38A, 39A) of each said end sections (38,39). A system according to Claim 1, 2 or 3 in which the portions of said centre section (26,37) outboard of said transducers (29;40) and the portions of said outer sections (27,28;38,39) inboard of said transducers (29;40) act as operculate to the respective transducers. A system according to Claim 4 in which said sections are filled with acoustical insulation material. A system according to Claim 3 which includes outer or side speaker components (42,43) on respective sides of said first mentioned speaker component (35) and being operatively connected thereto, each said outer or side speaker component (42;43) including a pair of outwardly facing transducers (42A,42B;43A,43B) and an enclosure (44A) for said transducers, the transducers of each pair of transducers (42A,42B;43A,43B) being situated back to back and spaced inwardly from opposing end walls (45,46;47,48) of said enclosure, a plurality of apertures (50A) formed through said walls opposite to said transducers and baffle means (49) operculating said apertures. A system according to Claim 6 wherein the baffle means (49) comprise a truncated cylinder secured around each of said apertures with the inner end being operatively adjacent said transducer (42A, 42B;43A,43B), the outer end (5) being truncated at an angle of approximately 35° 16', the axis of the ellipses formed by said truncation being rotated through 45° to the horizontal. An optimal shadow omniphonic microphone and loudspeaker system comprising in combination an omniphonic microphone component (25), a speaker component (35) and electronic means (30,,41) coupling the microphone and speaker components for processing signals from the microphone component and transmitting signals to the speaker component, each of said microphone and loudspeaker components including a substantially cylindrical module (25;35) with a longitudinal axis and comprising a centre section (26;37) with two elliptical outer end faces (26A,26B;37A,37B) truncated at approximately one half the dihedral angle of a regular tetrahedron and two end sections (27,28;38,39) at opposite ends of the centre section in longitudinal alignment therewith, each end section having an elliptical inner end face (27A,28A;38A39A) confronting a respective one of the outer end faces (26A,26B; 37A,37B) of the centre section (26;37), each said inner end face (27A,28A;38A,39A) and the outer end face (26A,26B;37A,37B) confronted thereby lying in a substantially parallel, spaced planes, and each elliptical and face (26A,26B,27A,28A;37A,37B,38A,39A) of the centre section and the end sections having a long axis oriented at approximately 45° to a horizontal plane, a microphone transducer (29)situated centrally in each of said outer end faces (26A,26B) of said centre section (26) of said microphone component and said inner end faces (27A,28A) of each of said end sections (27,28) of said microphone component, and a speaker transducer (40) situated in and spaced in from each of said outer end faces (37A,37B) of said centre section (37) of said speaker component and a further speaker transducer (40) situated in and spaced outwardly from the inner end faces (38A, 39A) of each of said end sections (38,39). An operculum acting as a baffle means for use with a loudspeaker component and comprising a truncated cylinder (49) secured adjacent a loudspeaker transducer (42A,42B) with an inner end being operatively situated to said transducer, and an outer end (50) being truncated at approximately one half the dihedral angle of a regular tetrahedron, the long axes of the ellipses formed by said truncation being oriented at approximately 45° to the horizontal.

Inventors: WEHNER RAYMOND, WEHNER, RAYMOND
Applicants: WEHNER RAYMOND, WEHNER, RAYMOND
Application year: 1987
Main classification: H04R5
IPC codes: H04R5, H04R1