Multi-mode audio amplifiers

A multimode audio amplifier comprising:

• a mode controller configured to provide a control signal;
• at least one multimode module, wherein each of the multimode modules is configured to operate in one of a plurality of operating modes, wherein the operating modes are selected in response to the control signal, wherein changing the operating modes results in a measurable change in at least one characteristic of the multimode audio amplifier, and wherein the characteristics of the multimode audio amplifier include
• signal to noise ratio (SNR),
• total harmonic distortion and noise (THD+N),
• input to output delay,
• power consumption, and
• efficiency;
• and
• a variable-length finite impulse response (FIR) filter configured to provide an output signal based on an input signal, wherein a length of the variable-length FIR filter is selected in response to the control signal, wherein the length of the variable-length FIR filter represents at least one of
• an order of the variable-length FIR filter, and
• a number of taps of the variable-length FIR filter, and
• wherein the variable-length FIR filter comprises
• a first fixed-length FIR filter configured to provide a first filtered signal based on the input signal,
• a second fixed-length FIR filter configured to provide a second filtered signal based on the first filtered signal, and
• an output module configured to provide one of the first filtered signal and the second filtered signal as the output signal in response to the control signal.