Sound reproduction system
First Claim
1. A sound reproduction system having an audio amplifier and a speaker coupled to the output of the audio amplifier, said speaker having an acoustic cone and a coil mandrel with a drive coil wound thereon, characterized byfirst feedback means for applying degenerative feedback to said audio amplifier in proportion to the current flowing through said drive coil;
- a feedback coil wound either under or over said drive coil on said coil mandrel;
second feedback means including said feedback coil for applying degenerative feedback to said audio amplifier in proportion to the voltage induced in said feedback coil by the motion at the speaker cone; and
said first and second feedback means being arranged in an additive relationship so that the total degenerative feedback applied to said audio amplifier is proportional to the sum of the output of said first and second feedback means for preventing acoustical peaks from being produced in the audio spectrum of said speaker by either a peak in the impedance versus frequency characteristic curve of said drive coil caused by a mechanical resonance of said speaker'"'"'s moving parts or a valley in said curve caused by an electromechanical resonance in the series circuit comprising the electrical self-inductance of said drive coil and the apparent capacitance of the moving mass due to said cone, said mandrel and said coils.
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Accused Products
Abstract
A speaker which is driven by an audio amplifier has a feedback coil wound on the coil mandrel adjacent to the speaker'"'"'s drive coil. A first degenerative feedback element is provided for applying degenerative feedback to the audio amplifier in proportion to the current flowing through the speaker'"'"'s drive coil. A second degenerative feedback elements is provided for applying degenerative feedback to the audio amplifier in proportion to the voltage induced in the feedback coil. The first and second degenerative feedback elements are arranged to be additive so that the total degenerative feedback applied to the audio amplifier is equal to the sum of the degenerative feedback from both degenerative feedback elements to thereby prevent acoustical peaks from being produced in the audio spectrum of the speaker.
30 Citations
11 Claims
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1. A sound reproduction system having an audio amplifier and a speaker coupled to the output of the audio amplifier, said speaker having an acoustic cone and a coil mandrel with a drive coil wound thereon, characterized by
first feedback means for applying degenerative feedback to said audio amplifier in proportion to the current flowing through said drive coil; -
a feedback coil wound either under or over said drive coil on said coil mandrel; second feedback means including said feedback coil for applying degenerative feedback to said audio amplifier in proportion to the voltage induced in said feedback coil by the motion at the speaker cone; and said first and second feedback means being arranged in an additive relationship so that the total degenerative feedback applied to said audio amplifier is proportional to the sum of the output of said first and second feedback means for preventing acoustical peaks from being produced in the audio spectrum of said speaker by either a peak in the impedance versus frequency characteristic curve of said drive coil caused by a mechanical resonance of said speaker'"'"'s moving parts or a valley in said curve caused by an electromechanical resonance in the series circuit comprising the electrical self-inductance of said drive coil and the apparent capacitance of the moving mass due to said cone, said mandrel and said coils. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for counteracting the deleterious acoustical effects of an impedance peak and an impedance valley in the lower frequency end of the impedance versus frequency characteristic curve of a sound reproduction system which includes a speaker having an acoustic cone and a coil mandrel with a drive coil wound on the coil mandrel and an audio amplifier coupled to the drive coil, said apparatus comprising:
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first feedback means for applying degenerative feedback to said audio amplifier in proportion to the current flowing through said drive coil; a feedback coil wound under or over said drive coil on said coil mandrel; second feedback means including said feedback coil for applying degenerative feedback to said audio amplifier in proportion to the voltage induced in said feedback coil by the motion of the speaker cone; and said first and second feedback means being arranged in an additive relationship such that the total degenerative feedback applied to said audio amplifier is proportional to the sum of the output of said first and second feedback means for causing said second feedback means to compensate for the deficiencies of said first feedback means at said impedance peak and for causing said first feedback means to compensate for the deficiencies of said second feedback means in said impedance valley to provide a smooth acoustical output in the frequency range of said impedance peak and impedance valley.
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Specification