Electrical audio signal processing systems and devices – Electro-acoustic audio transducer – Electromagnetic
Reexamination Certificate
2005-01-25
2005-01-25
Kuntz, Curtis (Department: 2643)
Electrical audio signal processing systems and devices
Electro-acoustic audio transducer
Electromagnetic
C381S396000, C381S412000, C381S414000
Reexamination Certificate
active
06847726
ABSTRACT:
Loudspeaker and other transducers of the dual-voice-coil/dual-magnetic-gap type can be improved by the addition of one or more annular shorting rings strategically located in the vicinity of the two magnetic gaps. The shorting rings have no effect on a steady state magnetic field but act in opposition to any change in flux density or any displacement of the flux lines such as those that occur under the loading imposed when the voice coils are driven hard with audio frequency current. The location of the shorting rings determines their effect: location close to a voice coil reduces the voice coil inductance, location entirely within the magnetic flux loop centerline favors reduction of second harmonic distortion and higher order even harmonic distortion, a centered location on the flux loop centerline, i.e. centered in the magnetic gap, favors reduction of third harmonic and higher odd order harmonic distortion, while location outside the flux loop as defined by its center line but near the voice coil acts to generally reduce harmonic distortion and reduce the voice coil inductance. Thus a plurality of rings can be strategically deployed at different locations so as to optimally suppress both even and odd order harmonic distortion and to reduce the voice coil inductance.
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Button Douglas J.
Hyde Ralph E.
Salvatti Alex V.
Brinks Hofer Gilson & Lione
Dabney Phylesha
Harman International Industries Incorporated
Kuntz Curtis
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