Setting the levels equally to start would help, but doesn't control when someone suddenly gets loud. With compression, you can increase quiet sounds, decrease loud sounds, or both.

https://en.wikipedia.org/wiki/Dynamic_range_compression

A type of compressor used to limit the maximum signal is a limiter. "Limiters are common as a safety device in live sound and broadcast applications to prevent sudden volume peaks from occurring."

https://en.wikipedia.org/wiki/Limiter