R55 HK Subwoofer Signal - Where easiest to tap
 

I've hunted for this but not found an answer here.

I have a 12 R55 S and am planning on adding an amp and sub to my Harman Kardon (HK) system. I'd like to know the easiest (closest) place to get full range signal to the rear of the vehicle.

My amp has a switch for input sensitivity:

Low-Level: 150 mV - 4 V
High-Level: 400 mV - 11 V

I understand the rear speakers may have a crossover at 40Hz or some other point.

I understand that the HK amp is located in the rear of the vehicle.

I would expect there is full-range, low-level signal feeding the HK amp at the rear.

I would like to tap this full range low level wire and feed it to the RCA input on my amp. I figure I can set my amp to 'high' as the HK signal may be above 4V max.

What color/position wires do I need to tap at the HK amp to do this?

Do I just take a set of RCA cables, cut them, and splice the bare ends to the taps?

Else, do I have to take speaker level signal and use a LOC to convert down?

Not sure if this applies to the Gen 2 HK system, but there might be some useful info here:

https://www.northamericanmotoring.co...ml#post3604109

Post 34 of this thread describes how a 6channel amp replaced the the HK amp in an R50. There are also links to the pin out diagrams for the two HK plugs.

This will make it very easy:
https://www.integralaudio.com/index....t-harness.html

Thanks for the suggestions.
I've seen that harness splitter that connects to the driver footwell.
I still don't know if it is converting speaker or RCA signal. I suspect it's RCA at >4v. If that's the only place I can splice, I guess I will be cutting a set of RCA cables to tap in.
I presume the signals are volume controlled, not constant?

As a follow-up, I got by IA box installed.

I tapped the front speakers from the driver footwell. I used Red wire taps with spade connectors. Don't use Blue wiretaps as they are too large a gauge to pierce the signal wire insulation. Wasted an hour getting intermittent signal that way...

No LOC is needed. Just tap directly from source to the RCA wires.

I ended up intentionally swapping negatives on the Left and Right speaker wires to supply the SW amp (+R/-L and +L,-R). If I recall correctly, that provides a mono source.

I tried using conventional +/- on each (for a stereo signal supply to the amp) but the results were very wonky when balance was adjusted off center.

I ended up choosing low signal input and max range (8v). Gain on my RF PBR500X1 amp is at maybe 1/4.

Remote level control is a necessity. I tend to vary from near zero to 3/4 depending on source and music type.


Overall, the improvement in low end is pretty nice. I have the box crossed relatively low (~70Hz) and the bass on the HK unit set to -3.