HK stereo, wiring for aftermarket sub

[kvande]

Hi, I know there are a dozen of these threads in this forum already, but I failed to find the info I’m looking for. I’m going to add an aftermarket sub to my HK system. I will use an Audicontrol (LC6i) high to low converter, but I am not sure which wires to connect it to. I am not planning to go the whole route with replacing head unit and HK amp.

From what I’ve learned from other threads it seems like the output from the head unit to the HK amp is at a close the maximum output all the time (the volume from the HK amplifier is adjusted by other means), so tapping into those wires with the Audicontrol seems like a bad idea? Since I am just going to add a sub with limited frequency response I guess I could get a signal from the wires running to the 6x9”, but is that signal already equalized in the HK amp (that might give a none optimal sound from my aftermarket sub)?

And if I am I to use the signal for the 6x9”, does anyone known the colour coding for those wires?

All advice appreciated.