The Lumin project is a workalike of the BBE Sonic Stomp / Sonic Maximizer. It’s based on work done by Bajaman (documented on FSB) and Sebastian Montti (stm) on DIYStompboxes in recreating the functionality of BBE’s proprietary NJM2150AD chip.
I intentionally designed this circuit around six dual op-amps instead of a quad and a dual like most other comparable projects. Your quad op-amp choices are pretty limited, but with duals you have a lot of other options like the NE5532 or OPA2134 if you want to try something different.
This project also has a midrange knob, giving you an additional frequency band to play with, and optional switches that allow you to change the frequencies for the Process (high) and Contour (low) knobs.