well there are different kinds of filters. but the filter effect is basically filtering out certain eqs and bringing others in more.
so the high-pitch filter is basically lowering the bass, increasing mids and highs at first, then decreasing mids and leaving only increased highs.
for the low-pitch filter it would be increasing bass, decreasing mids first and then decreasing highs.
thats how it sounds to my ears. maybe watch a couple of vids where people are mixing with filters and then play around and try to mimic the effect using eqs.