Abstract: An audio system includes an enclosure, a speaker disposed in the enclosure, an audio source for providing an audio signal, and a controller. The controller is connected to the speaker and configured to drive the speaker according to the audio signal. The audio system further includes a wireless personal area network interface connected to the controller. The wireless personal area network interface can communicate with a wireless mobile device to effect settings changes for the audio system and to perform calibration for the audio system. Calibration can include near and far measurements using the microphone of the wireless mobile device.

Abstract: A power amplifier is described that includes an amplification circuit and a linear regulator. The amplification circuit amplifies an input signal to produce an output signal and provides a feedback signal for tracking the expected power requirements of the output signal. The linear regulator is connectable for receiving as inputs the feedback signal from the amplification circuit and a plurality of fixed voltage supply rails. The linear regulator provides as an output at least one voltage supply to the amplification circuit. In at least one mode of operation, the at least one voltage supply provided to the amplification circuit tracks the expected output requirements of the amplification circuit between two of the plurality of fixed voltage supply rails.