Just did an upgrade of the OEM Alpine ICE sub in the boot.
Bought a Infinity Basslink II and placed it in the sparewheel trunk.
http://www.infinitysystems.com/car/product...Region=USA
Used the speaker cables to the 2 OEM sub coils and put them in the high line in on the sub.
Works great on low to medium volume, but when I crank it the sub cuts. I guess the input is just to much for the sub to handle. I have turned the SUB volume way down on the main unit and that helped some.

I just wanted to hear if anyone know 100% what is + and - on the 4 speakercables that go into the sub-box?
I have searched the pdf that Alex posted on the electric system, but it doesn't say which cables is what.....

Regards
Eirik FL2, TD4 HSE
The flaming Orange!

The output to the sub is a low impedance one. A speaker output in other words.
The power amplifier may not have an output relative to ground. It may be a bridged output.
But if it is an output relative with GND, then it is easy to know which one is "-" (GND), with the use of a multimeter.

Anyway, the voltage levels at sub output are quite high comparing with the line in input needs of an amplifier.
For adaption the theory says that you may need to use a low resistance load (in order to close the power output stage and not let it float) in parallel with a resistive divider.
Just like the one here: http://www.tkk.fi/Misc/Electronics/circuits/speaker_to_line.html

Was hoping you'd stop by Alex
The Sub has a high-level input on the amp so it is designed to connect speaker level input to the amp.
When using a volt meter on DC I was able to see what gave me + V and -V so I guess it's ok.

But the SUB level is still to high for the subamp to cope. I am a little unsure about my ground point.......used one of the screws that holds the oem subbox in the trunk. FL2, TD4 HSE
The flaming Orange!

If you are talking about the ground point of the sub power supply, then yes, any screw that is in touch with the metal body is ok.
As for the sub level input, if it is still too high, then use that resistive divider.
Or depending on the situation, use a symmetrical resistive divider, like this (the second one): http://www.sengpielaudio.com/calculator-voltagedivider.htm

Thank you for the responds Alex.
I solved the issue by using just one of the two sub-lines.
Now it's working perfectly.
Do you know how the 2 subs work. Is it a push pull setup or are they just playing in parallel 0 degrees? FL2, TD4 HSE
The flaming Orange!