what is the role of filter1 and filter2?
 

Hello.

I cannot quite understand the role of the two filters.
Can someone explain me what they really do?
Why do I need two filters?

a simple example is...

You have resonant 303 type noise using a LPF burbling away and you want to then add a HPF to get rid of the bass.

or

A pad sound uses an phaser like lfo to band pass filter with a low pass filter cutting out overall brightness

Also if you use 2 of the same type of filters together you create a sharper cut off and res.

and lastly

You create a sound with 2 different filter settings and use the filter balance to morph between them.

Thanks for the explanation! =)

Here's my favorite application of the two filters: make a resonant sub bass patch. Stack a bunch of triangle waves right? Right. Put the filters in serial 2 (4 poles). The 4poles make a steeper cutoff and make the resonance more noticeable.
Use HP w a decent amount of resonance. Odd to put HP on a sub? Maybe, but the patch is just a fundamental to shake things, not really all over the place melodically, just within an octave or so. Use the cutoff to dial in where things really shake.
You'll find as you work your way up the octave on the keyboard it starts to get less resonant as you get away from the knee where you just tuned your filter to.
Now use the LP of the second filter to make the top end of your range resonate in the same way. This should give you a good octave or so off extremely resonant sub bass.