Does anyone have the crossover circuit diagram for the KEF iQ 50 Speaker system?
The best way to find out is to call the manufacturer for a schematic. Otherwise you could pull the crossover out and examine it. I’m wondering how you are going to know if a tweak is needed by knowing its configuration? To consider redesigning the crossover you need both measurement equipment like Arta http://www.fesb.hr/~mateljan/arta/ and software like LspCAD http://www.ijdata.com/ along with a good microphone and sound card. I personally prefer active crossovers. This speaker possibly could be improved by converting it to active but not by simply replacing the internal crossovers with Linkwitz Riley active. The complete crossover includes equalization in addition to the simple LR-4 slopes. You could create a proper active crossover with the Behringer DCX digital crossover but still need the Arta measurement system and microphone to do it properly. The measurements must
