Patent ID: 7321661

Claim:
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.