US 7,321,661 B2 | ||
Current feedback system for improving crossover frequency response | ||
Gerald R. Stanley, Osccola, Ind. (US) | ||
Assigned to Harman International Industries, Incorporated, Northridge, Calif. (US) | ||
Filed on Oct. 30, 2003, as Appl. No. 10/697,626. | ||
Prior Publication US 2005/0094830 A1, May 05, 2005 | ||
Int. Cl. H04R 3/00 (2006.01); H03G 5/00 (2006.01); H03F 21/00 (2006.01) |
U.S. Cl. 381—111 [381/98; 381/99; 381/120; 381/116] | 43 Claims |
1. A loudspeaker system for receiving an incoming electrical signal and transmitting an acoustical signal, the loudspeaker
system comprising:
a driver circuit comprising a first passive filter coupled to a first speaker driver and a second passive filter coupled to
a second speaker driver wherein a first filter impedance of the first passive filter is substantially matched to a first cold
impedance of the first speaker driver, and a second filter impedance of the second passive filter is substantially matched
to a second cold impedance of the second speaker driver; and
a power amplifier having an input and an output, wherein the power amplifier includes a current-feedback amplifier configured
to create a desired impedance at the output that is between about 25 percent and about 400 percent of a combined input impedance
of the first filter impedance, the first cold impedance, the second filter impedance, and the second cold impedance
the power amplifier comprising a current monitor operable to sense an output current at the output, and a feedback circuit
coupled with the current monitor, the feedback circuit operable to generate a feedback signal to create the desired impedance
at the output so that variations in frequency response as a result of impedance changes of the first speaker driver and the
second speaker driver are minimized;
wherein the input of the power amplifier receives the incoming electrical signal, and the output of the power amplifier is
coupled to the input of the driver circuit.
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