Heyall, Yesterday I got this idea in class, one student was trying to biuld a wahwah effect filter to his guitar pedal and when I saw the circuit diagram, and how easily it was made made me wonder. "What if I look up the filter types from the internet, buy the components for each one and build them, then just attach all together and make a filterbank?" I studied electronics for 3 years and now I study to be automation mechanic. I have a friend who got really excited about the idea (has background in electronics and electronic music) and he was ready to try out these circuits shown in internet. What I've gathered the filters are commonly made with a op amp and couple of condensators or coil's. I'm still wondering if it's possible to make a cutoff filter to those? And how we're able to switch between serial and parallel and so on. Switching between filters is easy with a knob cause they all are so small circuits, usually work with only 9V too. So if you have any tips, advices, or links around the internet for different filter types or other circuit diagrams or just about anything related, don't be afraid to point out! Hopefully we find something really alien effects, harmonics, distortions and filter types never found before!! EVERYTHING WILL CHANGE WHEN THIS FILTER UNIT IS READY! We gonna experiment the shit out of this! (Or it ill be just shit.) Cheers!