What is used to control the input level of an audio signal when it first enters a mixer?

Gain is the term used to control the input level of an audio signal when it first enters a mixer. When a signal is routed into a mixer, it is essential to adjust the gain to ensure that the audio is within the optimal range for processing. This involves amplifying or reducing the signal to a level that prevents distortion and allows for a clean sound before any effects or adjustments are made further down the signal chain.

Setting the gain correctly is crucial because it establishes a strong foundation for the mix, ensuring that subsequent adjustments made via other controls—like faders, EQ, or pan—will be more effective. A well-set gain ensures that the mixer can handle the dynamics of the audio signal without introducing noise or clipping, which are detrimental to sound quality.