Inhibits or prevents a portion of a signal from getting through – limiting the signal. This is most commonly used to limit bass output so that a speaker with little low frequency extension does not attempt to play low bass passages. It can also be used to limit a speaker’s output, particularly very loud, very low bass from a subwoofer. Essentially, a crossover is a form of limiter shunting some audio frequencies away from various circuits or speaker drivers while allowing others to pass.