Gain and input sensitivity explained

Gain and sensitivity are related, not identical

A fixed-gain amplifier multiplies input voltage by a stated amount. A gain of 26 dB is about 20 times voltage; 32 dB is about 40 times. Input sensitivity states the voltage required to reach rated output under specified conditions.

Sensitivity changes with rated output and load, while voltage gain describes the ratio itself. Check whether an input control changes gain or simply attenuates a fixed-gain stage.

Why it matters in a cinema rack

If amplifier sensitivity is too high for the system, processor noise and hiss can be magnified, especially through efficient horn loudspeakers. If sensitivity is too low, the processor may run out of clean output voltage before the amplifier reaches full power.

Mixing amplifiers with different gain is possible, but processor trims, noise floor and maximum output must be considered together. Matching SPL at one calibration level does not automatically equalise available headroom.

Balanced and unbalanced levels

Balanced outputs often support more voltage than consumer RCA outputs, but connector type alone is not the specification. Check the processor’s maximum clean output, the amplifier’s selected input mode and any gain or sensitivity switches. Conversion cables can change level or grounding behaviour.

Commission the chain

Choose a consistent gain strategy where practical. With loudspeakers protected or test loads connected, use calibrated signals and meters to verify processor headroom, amplifier output and channel alignment. Set trims for acoustic calibration only after the electrical path is understood.