A Crossover (or Frequency Divider) is a filter circuit that divides the audio signal into different frequency ranges and sends each one to the correct speaker.

It ensures that only the right frequencies reach each speaker (driver), as each one is designed to reproduce only a part of the sound spectrum.

In a two-way speaker system, the crossover works like this:

1. It uses a high-pass filter to send only the high frequencies to the tweeter.

2. It uses a filter Low-pass filter to send only the bass frequencies to the woofer. This not only optimizes the performance of each speaker, but also protects them. Sending low frequencies to a delicate tweeter, for example, would instantly damage it.