Which component serves as a barrier for undesired frequencies in an audio system?

The crossover is the component that serves as a barrier for undesired frequencies in an audio system. It functions by dividing the audio signal into different frequency ranges and directing them to the appropriate speakers, such as tweeters for high frequencies and woofers for low frequencies.

By doing this, the crossover prevents speakers from trying to reproduce frequency ranges they are not designed for, which can lead to distortion and inefficiency. For example, a subwoofer is designed to handle low frequencies, while a tweeter is designed to handle high frequencies. The crossover ensures that each speaker only receives the frequencies they are capable of handling, thus optimizing the overall sound quality and performance of the audio system.

Additionally, while amplifiers increase the power of the audio signal and speakers convert electrical signals into sound, neither of them specifically functions to segregate frequencies within the system, which is the primary role of the crossover.