A fast response time, self-activating, adjustable threshold limiter including a limiting element LE, a first coupling element CE.sub.1 electrically connected from a signal node of LE to a control input of LE, and a second coupling element CE.sub.2 electrically connected from the control input of LE to a nominal node of LE. An initial bias (control) voltage is also supplied to the control input of LE to dynamically control the limiting threshold for the limiter. Embodiments include usage of self-activating adjustable power limiters in combination with series switch components in a switch circuit in lieu of conventional shunt switches.

A method of controlling an audio system includes generating a situation response model for a situation parameter, determining a situation parameter value, and at least one of (1) providing an audio system output as a function of the situation response model and the situation parameter value and (2) receiving an audio system input as a function of the situation response model and the situation parameter value.

A method of controlling an audio system includes generating a situation response model for a situation parameter, determining a situation parameter value, and at least one of (1) providing an audio system output as a function of the situation response model and the situation parameter value and (2) receiving an audio system input as a function of the situation response model and the situation parameter value.

A fast response time, self-activating, adjustable threshold limiter including a limiting element LE, a first coupling element CE.sub.1 electrically connected from a signal node of LE to a control input of LE, and a second coupling element CE.sub.2 electrically connected from the control input of LE to a nominal node of LE. An initial bias (control) voltage is also supplied to the control input of LE to dynamically control the limiting threshold for the limiter. Embodiments include usage of self-activating adjustable power limiters in combination with series switch components in a switch circuit in lieu of conventional shunt switches.

Disclosed are a load resistor control based signal amplification apparatus and an audio terminal including the same. The signal amplification apparatus according to the exemplary embodiment of the present disclosure selects at least one load resistor based on a load value of an output terminal connected to an output end and controls a current by means of at least one selected load resistor to amplify the audio input signal and output the audio output signal.