What's the interpretation of this Low pass filter spec?

1. How do you read a low-pass filter?
2. What is the purpose of a low-pass filter?
3. What Should low-pass filter be?

How do you read a low-pass filter?

What is a low-pass filter? A low-pass filter (LPF) is an audio signal processor that removes unwanted frequencies from a signal above a determined cutoff frequency. It progressively filters out (attenuates) the high-end above its cutoff frequency while allowing the low-end to pass through, ideally without any changes.

What is the purpose of a low-pass filter?

A low-pass filter allows for easy passage of low-frequency signals from source to load, and difficult passage of high-frequency signals. Inductive low-pass filters insert an inductor in series with the load; capacitive low-pass filters insert a resistor in series and a capacitor in parallel with the load.

What Should low-pass filter be?

As a general rule, the Low-Pass Filter should be set at a value approximately equal to (or below) 70% of your main speaker's lowest frequency response. For example, your speaker's frequency response goes down to 43Hz. 70% of 43Hz equals 30.1, so you should set the subwoofer's low pass filter to 30Hz.