A low–pass filter (LPF) is a filter that passes signals with a frequency lower than a selected cutoff frequency and attenuates signals with frequencies higher than the cutoff frequency.

A high–pass filter’s task is just the opposite of a low–pass filter: to offer easy passage of a high-frequency signal and difficult passage to a low-frequency signal.

In a nutshell, these filters help you to clean up your mixes by removing frequencies that are not being used by instruments of high or low frequency signals.