Filter modules shape the sound going through them by removing or reducing the strength of some the “harmonic” components in the original sound. Some filters have just a gentle effect on a sound; some have quite a drastic effect. Explore the differences, while getting the technical terms “poles” and “decibels per octave” explained.
Filter slopes are first discussed on page 18 of Patch & Tweak, and further explained on page 165. Read more about PATCH & TWEAK here.