Input Sensitivity
Input sensitivity is the signal voltage needed to produce the stated reference or rated output.
The reference output and gain or volume setting define the meaning. It is separate from maximum input voltage, which describes an overload limit.
Input Sensitivity — Power Amp
For a power amplifier, sensitivity can be stated for rated power or another reference such as one watt. The required input changes with the chosen gain setting.
Compare the same output reference, gain and input path with the preamplifier’s available signal. A lower sensitivity voltage means less input is required for that result, not automatically better sound or more maximum power.
Input Sensitivity — Headphone Amp
For a headphone amplifier, sensitivity links an input voltage to a specified output under the stated load and gain. It describes signal-level matching to the source.
Compare gain, volume and headphone-load conditions. Do not treat the sensitivity as the largest allowable input; the overload ceiling is a separate measurement. Input impedance is also a different property.
Input Sensitivity — Subwoofer
For an active subwoofer, sensitivity describes the input signal needed for a specified output with the stated level-control setting. Line and speaker-level inputs can have different figures.
Compare the same input and output reference. A sensitivity figure is not the driver’s acoustic sensitivity or the maximum input limit. Level control can change how much source voltage is needed for the measured result.