Abstract: A distortion compensation system minimizes distortion in an audio system by monitoring a supply voltage and adjusting a clipping threshold and/or compression knee. An adjustable gain circuit controls the gain of the audio signal according whether the audio signal exceeds a variable threshold. The variable threshold is adjusted within a threshold range based on the supply voltage. Distortion due to clipping of the audio signal is minimized while available power at any given time is maximized.

Abstract: A system and method for updating the software of a digital audio amplifier. The digital data used to update the amplifier's software is transmitted as an analog signal over analog audio channels to the amplifier. The amplifier is adapted to recognize when an audio signal should be used to update the amplifier's software, instead of merely driving the speakers with the audio signal. Upon receiving such an audio signal, the amplifier decodes the analog signal into digital instructions. The digital instructions are processed to reconfigure the amplifier's operation.

Abstract: A sound processing system for a vehicle includes a sound processor that is configured to mix at least one real audio input signal to form at least one virtual output signal. At least one audio signal that is available to drive at least one loudspeaker may be formed using the combination of the virtual output signal and the real audio input signal. The virtual output signal may be post processed to form a predetermined frequency range of the audio signal prior to being combined with the real audio input signal. The audio signal may be created by mixing the real audio input signal with the post processed virtual output signal. Alternatively, the audio signal may be formed by mixing the real audio input signal to form a real audio output signal, and then summing the real audio output signal with the post processed virtual output signal. Mixing may be performed with a crossbar mixer included in the sound processor.