Double voice coil loudspeaker

Claim 2

A loudspeaker of the electrodynamic type, comprising dual voice coils driving a substantially frustroconical speaker cone, whose sound output is monaural and whose sound intensity is equal and audible at each ear, said dual voice coils comprising, an outer voice coil bobbin, an inner voice coil bobbin, mounted concentrically with respect to each other, means securing one of said voice coil bobbins to said speaker cone in axially extending relation therefrom, means comprising an insulating and spacing collar attached to said outer voice coil bobbin and attached to and supporting said inner voice coil bobbin in spaced relation and defining therebetween an annular sound compression chamber, means for creating a magnetic field in juxtaposition to each of said bobbins, said magnetic means comprising a first pole having a core portion extending within the inner voice coil bobbin, a second pole comprising a tubular portion extending into said sound compression chamber, and pole faces disposed adjacent the outer surface of the outer voice coil bobbin and cooperating with said second pole to form a gap, said second Pole tubular portion having on the inner surface a non-magnetic metallic coating to isolate the magnetic field of said second pole from the magnetic field of said first pole, a first electrical conduit attachable to an amplifier, and to said outer voice coil bobbin, a second electrical conduit attachable to an amplifier and to said outer voice coil bobbin, a first auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, a second auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit and resistance means interposed in said second electrical conduit intermediate said first auxiliary electrical conduit and said second auxiliary electrical conduit said electrical conduits and auxiliary electrical conduits and voice coils being arranged in inphase relation.

Claim 3

A loudspeaker of the electrodynamic type, comprising dual voice coils driving a substantially frustro-conical speaker cone, whose sound output is monaural and whose sound intensity is equal and audible at each ear, said dual voice coils comprising, inner and outer voice coil bobbins mounted concentrically with respect to each other, means securing said outer voice coil bobbin to speaker cone in axially extended relation therefrom, a spacing collar of magnetic insulating material secured to both said inner and outer voice coil bobbins to rigidly support said bobbins in concentric relationship and to define an annular sound compression chamber therebetween, means for creating a magnetic field in juxtaposition to each of said bobbins, said magnetic means comprising a permanent magnet, a first pole attached to said permanent magnet and provided with a core portion extending within the inner voice coil bobbin, a second pole attached to said permanent magnet and mounted concentrically with respect to said first pole and provided with a tubular portion extending into said sound compression chamber, a gap formed between said first and second poles, said second pole tubular portion having on the inner surface a nonmagnetic metallic coating to control the effective force of the magnetic field of said first pole, a first electrical conduit attachable to an amplifier, and to said outer voice coil bobbin, a second electrical conduit attachable to an amplifier and to said outer voice coil bobbin, a first auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, a second auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, and resistance means interposed in said second electrical conduit intermediate said first auxiliary electrical conduit and said second auxiliary electrical conduit said electrical conduits and auxiliary electrical conduits and voice coils being arranged in in-phase relation.

Claim 4

A loudspeaker of the electrodynamic type, comprising dual voice coils driving a substantially frustro-conical speaker cone, whose sound output is monaural and whose sound intensity is equal and audible at each ear, said dual voice coils comprising, inner and outer voice coil bobbins mounted concentrically with respect to each other, means securing said outer voice coil bobbin to speaker cone in axially extended relation therefrom, a spacing collar of magnetic insulating material secured to both said inner and outer voice coil bobbins to rigidly support said bobbins in concentric relationship and to define an annular sound compression chamber therebetween, means for creating a magnetic field in juxtaposition to each of said bobbins, said magnetic means comprising a permanent magnet, a first pole attached to said permanent magnet and provided with a core portion extending within the inner voice coil bobbin, a second pole attached to said permanent magnet and mounted concentrically with respect to said first pole and provided with a tubular portion extending into said sound compression chamber, a gap formed between said first and second poles, said second pole tubular portion having on the inner surface a nonmagnetic metallic coating to control the effective force of the magnetic field of said first pole, a first electrical conduit attachable to an amplifier, and to said outer voice coil bobbin, a second electrical conduit attachable to an amplifier and to said outer voice coil bobbin, a first auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, a second auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, and resistance means interposed in said second electrical conduit intermediate said first auxiliary electrical conduit and said second auxiliary electrical conduit said electrical conduits and auxiliary electrical conduits and voice coils being arranged in in-phase relation.

Claim 5

A loudspeaker of the electrodynamic type, comprising dual voice coils driving a substantially frustro-conical speaker cone, whose sound output is monaural and whose sound intensity is equal and audible at each ear, said dual voice coils comprising, inner and outer voice coil bobbins mounted concentrically with respect to each other, means securing said outer voice coil bobbin to said speaker cone in axially extending relation therefrom, a spacing collar of magnetic insulating material secured to both said inner and outer voice coil bobbins to rigidly support said bobbins in concentric relationship and to define an annular sound compression chamber therebetween, means for creating a magnetic field consisting of a circular strap having an axial orifice and open opposite sides, a block formed in the circular strap opposite the axial orifice, said circular strap and block comprising a low loss permanent magnetic circuit, a first pole bar magnet attached to said block and provided with a core portion extending within the inner voice coil bobbin, a second pole attached to said block, mounted concentrically with respect to said first pole and Provided with a tubular portion extending into said sound compression chamber and forming part of said low loss magnetic circuit, the forward surface of said second pole forming the other end of said sound compression chamber, said inner and outer voice coil bobbins and said first and second poles extending axially through said axial orifice to form a first gap between said circular strap at said axial orifice and said outer voice coil bobbin, and a second gap formed between said first and second poles, said second pole tubular portion having on the inner surface a non-magnetic metallic coating to control the effective magnetic field between said first pole bar magnetic and said second pole low loss magnetic circuit, a first electrical conduit attachable to an amplifier, and to said outer voice coil bobbin, a second electrical conduit attachable to an amplifier and to said outer voice coil bobbin, a first auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, a second auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, and resistance means interposed in said second electrical conduit intermediate said first auxiliary electrical conduit and said second auxiliary electrical conduit said electrical conduits and auxiliary electrical conduits and voice coils being arranged in in-phase relation.

Claim 6

A loudspeaker of the electrodynamic type, comprising dual voice coils driving a substantially frustro-conical speaker cone, whose sound output is monaural and whose sound intensity is equal and audible at each ear, said dual voice coils comprising, inner and outer voice coil bobbins mounted concentrically with respect to each other, means securing said outer voice coil bobbin to said speaker cone in axially extending relation therefrom, a spacing collar of magnetic insulating material secured to both said inner and outer voice coil bobbins to rigidly support said bobbins in concentric relationship and to define an annular sound compression chamber therebetween, means for creating a magnetic field consisting of a circular strap having an axial orifice and open opposite sides, a block formed in the circular strap opposite the axial orifice, said circular strap and block comprising a low loss permanent magnetic circuit, a first pole bar magnet attached to said block and provided with a core portion extending within the inner voice coil bobbin, a second pole attached to said block, mounted concentrically with respect to said first pole and Provided with a tubular portion extending into said sound compression chamber and forming part of said low loss magnetic circuit, the forward surface of said second pole forming the other end of said sound compression chamber, said inner and outer voice coil bobbins and said first and second poles extending axially through said axial orifice to form a first gap between said circular strap at said axial orifice and said outer voice coil bobbin, and a second gap formed between said first and second poles, said second pole tubular portion having on the inner surface a non-magnetic metallic coating to control the effective magnetic field between said first pole bar magnetic and said second pole low loss magnetic circuit, a first electrical conduit attachable to an amplifier, and to said outer voice coil bobbin, a second electrical conduit attachable to an amplifier and to said outer voice coil bobbin, a first auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, a second auxiliary electrical conduit connected to said inner voice coil bobbin and to said second electrical conduit, and resistance means interposed in said second electrical conduit intermediate said first auxiliary electrical conduit and said second auxiliary electrical conduit said electrical conduits and auxiliary electrical conduits and voice coils being arranged in in-phase relation.